diff options
| author | Linus Torvalds <torvalds@linux-foundation.org> | 2020-12-17 22:22:17 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-12-17 22:22:17 +0100 |
| commit | 09c0796adf0c793462fda1d7c8c43324551405c7 (patch) | |
| tree | 90893d337b215482f059dd7e522279b23ffa0961 | |
| parent | Merge tag 'modules-for-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/gi... (diff) | |
| parent | tracing: Offload eval map updates to a work queue (diff) | |
| download | linux-09c0796adf0c793462fda1d7c8c43324551405c7.tar.xz linux-09c0796adf0c793462fda1d7c8c43324551405c7.zip | |
Merge tag 'trace-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt:
"The major update to this release is that there's a new arch config
option called CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS.
Currently, only x86_64 enables it. All the ftrace callbacks now take a
struct ftrace_regs instead of a struct pt_regs. If the architecture
has HAVE_DYNAMIC_FTRACE_WITH_ARGS enabled, then the ftrace_regs will
have enough information to read the arguments of the function being
traced, as well as access to the stack pointer.
This way, if a user (like live kernel patching) only cares about the
arguments, then it can avoid using the heavier weight "regs" callback,
that puts in enough information in the struct ftrace_regs to simulate
a breakpoint exception (needed for kprobes).
A new config option that audits the timestamps of the ftrace ring
buffer at most every event recorded.
Ftrace recursion protection has been cleaned up to move the protection
to the callback itself (this saves on an extra function call for those
callbacks).
Perf now handles its own RCU protection and does not depend on ftrace
to do it for it (saving on that extra function call).
New debug option to add "recursed_functions" file to tracefs that
lists all the places that triggered the recursion protection of the
function tracer. This will show where things need to be fixed as
recursion slows down the function tracer.
The eval enum mapping updates done at boot up are now offloaded to a
work queue, as it caused a noticeable pause on slow embedded boards.
Various clean ups and last minute fixes"
* tag 'trace-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (33 commits)
tracing: Offload eval map updates to a work queue
Revert: "ring-buffer: Remove HAVE_64BIT_ALIGNED_ACCESS"
ring-buffer: Add rb_check_bpage in __rb_allocate_pages
ring-buffer: Fix two typos in comments
tracing: Drop unneeded assignment in ring_buffer_resize()
tracing: Disable ftrace selftests when any tracer is running
seq_buf: Avoid type mismatch for seq_buf_init
ring-buffer: Fix a typo in function description
ring-buffer: Remove obsolete rb_event_is_commit()
ring-buffer: Add test to validate the time stamp deltas
ftrace/documentation: Fix RST C code blocks
tracing: Clean up after filter logic rewriting
tracing: Remove the useless value assignment in test_create_synth_event()
livepatch: Use the default ftrace_ops instead of REGS when ARGS is available
ftrace/x86: Allow for arguments to be passed in to ftrace_regs by default
ftrace: Have the callbacks receive a struct ftrace_regs instead of pt_regs
MAINTAINERS: assign ./fs/tracefs to TRACING
tracing: Fix some typos in comments
ftrace: Remove unused varible 'ret'
ring-buffer: Add recording of ring buffer recursion into recursed_functions
...
57 files changed, 1140 insertions, 415 deletions
diff --git a/Documentation/trace/ftrace-uses.rst b/Documentation/trace/ftrace-uses.rst index a4955f7e3d19..f7d98ae5b885 100644 --- a/Documentation/trace/ftrace-uses.rst +++ b/Documentation/trace/ftrace-uses.rst @@ -30,8 +30,8 @@ The ftrace context This requires extra care to what can be done inside a callback. A callback can be called outside the protective scope of RCU. -The ftrace infrastructure has some protections against recursions and RCU -but one must still be very careful how they use the callbacks. +There are helper functions to help against recursion, and making sure +RCU is watching. These are explained below. The ftrace_ops structure @@ -108,6 +108,58 @@ The prototype of the callback function is as follows (as of v4.14): at the start of the function where ftrace was tracing. Otherwise it either contains garbage, or NULL. +Protect your callback +===================== + +As functions can be called from anywhere, and it is possible that a function +called by a callback may also be traced, and call that same callback, +recursion protection must be used. There are two helper functions that +can help in this regard. If you start your code with: + +.. code-block:: c + + int bit; + + bit = ftrace_test_recursion_trylock(ip, parent_ip); + if (bit < 0) + return; + +and end it with: + +.. code-block:: c + + ftrace_test_recursion_unlock(bit); + +The code in between will be safe to use, even if it ends up calling a +function that the callback is tracing. Note, on success, +ftrace_test_recursion_trylock() will disable preemption, and the +ftrace_test_recursion_unlock() will enable it again (if it was previously +enabled). The instruction pointer (ip) and its parent (parent_ip) is passed to +ftrace_test_recursion_trylock() to record where the recursion happened +(if CONFIG_FTRACE_RECORD_RECURSION is set). + +Alternatively, if the FTRACE_OPS_FL_RECURSION flag is set on the ftrace_ops +(as explained below), then a helper trampoline will be used to test +for recursion for the callback and no recursion test needs to be done. +But this is at the expense of a slightly more overhead from an extra +function call. + +If your callback accesses any data or critical section that requires RCU +protection, it is best to make sure that RCU is "watching", otherwise +that data or critical section will not be protected as expected. In this +case add: + +.. code-block:: c + + if (!rcu_is_watching()) + return; + +Alternatively, if the FTRACE_OPS_FL_RCU flag is set on the ftrace_ops +(as explained below), then a helper trampoline will be used to test +for rcu_is_watching for the callback and no other test needs to be done. +But this is at the expense of a slightly more overhead from an extra +function call. + The ftrace FLAGS ================ @@ -128,26 +180,20 @@ FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED will not fail with this flag set. But the callback must check if regs is NULL or not to determine if the architecture supports it. -FTRACE_OPS_FL_RECURSION_SAFE - By default, a wrapper is added around the callback to - make sure that recursion of the function does not occur. That is, - if a function that is called as a result of the callback's execution - is also traced, ftrace will prevent the callback from being called - again. But this wrapper adds some overhead, and if the callback is - safe from recursion, it can set this flag to disable the ftrace - protection. - - Note, if this flag is set, and recursion does occur, it could cause - the system to crash, and possibly reboot via a triple fault. - - It is OK if another callback traces a function that is called by a - callback that is marked recursion safe. Recursion safe callbacks - must never trace any function that are called by the callback - itself or any nested functions that those functions call. - - If this flag is set, it is possible that the callback will also - be called with preemption enabled (when CONFIG_PREEMPTION is set), - but this is not guaranteed. +FTRACE_OPS_FL_RECURSION + By default, it is expected that the callback can handle recursion. + But if the callback is not that worried about overehead, then + setting this bit will add the recursion protection around the + callback by calling a helper function that will do the recursion + protection and only call the callback if it did not recurse. + + Note, if this flag is not set, and recursion does occur, it could + cause the system to crash, and possibly reboot via a triple fault. + + Not, if this flag is set, then the callback will always be called + with preemption disabled. If it is not set, then it is possible + (but not guaranteed) that the callback will be called in + preemptable context. FTRACE_OPS_FL_IPMODIFY Requires FTRACE_OPS_FL_SAVE_REGS set. If the callback is to "hijack" diff --git a/MAINTAINERS b/MAINTAINERS index 4654ce865358..c52fedb1a8e8 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -17983,6 +17983,7 @@ T: git git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git perf/core F: Documentation/trace/ftrace.rst F: arch/*/*/*/ftrace.h F: arch/*/kernel/ftrace.c +F: fs/tracefs/ F: include/*/ftrace.h F: include/linux/trace*.h F: include/trace/ diff --git a/arch/Kconfig b/arch/Kconfig index d4bdc19ed3ad..a08999dfcf16 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -143,6 +143,22 @@ config UPROBES managed by the kernel and kept transparent to the probed application. ) +config HAVE_64BIT_ALIGNED_ACCESS + def_bool 64BIT && !HAVE_EFFICIENT_UNALIGNED_ACCESS + help + Some architectures require 64 bit accesses to be 64 bit + aligned, which also requires structs containing 64 bit values + to be 64 bit aligned too. This includes some 32 bit + architectures which can do 64 bit accesses, as well as 64 bit + architectures without unaligned access. + + This symbol should be selected by an architecture if 64 bit + accesses are required to be 64 bit aligned in this way even + though it is not a 64 bit architecture. + + See Documentation/unaligned-memory-access.txt for more + information on the topic of unaligned memory accesses. + config HAVE_EFFICIENT_UNALIGNED_ACCESS bool help diff --git a/arch/csky/kernel/probes/ftrace.c b/arch/csky/kernel/probes/ftrace.c index 5264763d05be..ae2b1c7b3b5c 100644 --- a/arch/csky/kernel/probes/ftrace.c +++ b/arch/csky/kernel/probes/ftrace.c @@ -11,18 +11,25 @@ int arch_check_ftrace_location(struct kprobe *p) /* Ftrace callback handler for kprobes -- called under preepmt disabed */ void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip, - struct ftrace_ops *ops, struct pt_regs *regs) + struct ftrace_ops *ops, struct ftrace_regs *fregs) { + int bit; bool lr_saver = false; struct kprobe *p; struct kprobe_ctlblk *kcb; + struct pt_regs *regs; - /* Preempt is disabled by ftrace */ + bit = ftrace_test_recursion_trylock(ip, parent_ip); + if (bit < 0) + return; + + regs = ftrace_get_regs(fregs); + preempt_disable_notrace(); p = get_kprobe((kprobe_opcode_t *)ip); if (!p) { p = get_kprobe((kprobe_opcode_t *)(ip - MCOUNT_INSN_SIZE)); if (unlikely(!p) || kprobe_disabled(p)) - return; + goto out; lr_saver = true; } @@ -56,6 +63,9 @@ void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip, */ __this_cpu_write(current_kprobe, NULL); } +out: + preempt_enable_notrace(); + ftrace_test_recursion_unlock(bit); } NOKPROBE_SYMBOL(kprobe_ftrace_handler); diff --git a/arch/nds32/kernel/ftrace.c b/arch/nds32/kernel/ftrace.c index 3763b3f8c3db..414f8a780cc3 100644 --- a/arch/nds32/kernel/ftrace.c +++ b/arch/nds32/kernel/ftrace.c @@ -10,7 +10,7 @@ extern void (*ftrace_trace_function)(unsigned long, unsigned long, extern void ftrace_graph_caller(void); noinline void __naked ftrace_stub(unsigned long ip, unsigned long parent_ip, - struct ftrace_ops *op, struct pt_regs *regs) + struct ftrace_ops *op, struct ftrace_regs *fregs) { __asm__ (""); /* avoid to optimize as pure function */ } @@ -38,7 +38,7 @@ EXPORT_SYMBOL(_mcount); #else /* CONFIG_DYNAMIC_FTRACE */ noinline void __naked ftrace_stub(unsigned long ip, unsigned long parent_ip, - struct ftrace_ops *op, struct pt_regs *regs) + struct ftrace_ops *op, struct ftrace_regs *fregs) { __asm__ (""); /* avoid to optimize as pure function */ } diff --git a/arch/parisc/kernel/ftrace.c b/arch/parisc/kernel/ftrace.c index 63e3ecb9da81..0a1e75af5382 100644 --- a/arch/parisc/kernel/ftrace.c +++ b/arch/parisc/kernel/ftrace.c @@ -51,7 +51,7 @@ static void __hot prepare_ftrace_return(unsigned long *parent, void notrace __hot ftrace_function_trampoline(unsigned long parent, unsigned long self_addr, unsigned long org_sp_gr3, - struct pt_regs *regs) + struct ftrace_regs *fregs) { #ifndef CONFIG_DYNAMIC_FTRACE extern ftrace_func_t ftrace_trace_function; @@ -61,7 +61,7 @@ void notrace __hot ftrace_function_trampoline(unsigned long parent, if (function_trace_op->flags & FTRACE_OPS_FL_ENABLED && ftrace_trace_function != ftrace_stub) ftrace_trace_function(self_addr, parent, - function_trace_op, regs); + function_trace_op, fregs); #ifdef CONFIG_FUNCTION_GRAPH_TRACER if (dereference_function_descriptor(ftrace_graph_return) != @@ -204,17 +204,26 @@ int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, #ifdef CONFIG_KPROBES_ON_FTRACE void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip, - struct ftrace_ops *ops, struct pt_regs *regs) + struct ftrace_ops *ops, struct ftrace_regs *fregs) { struct kprobe_ctlblk *kcb; - struct kprobe *p = get_kprobe((kprobe_opcode_t *)ip); + struct pt_regs *regs; + struct kprobe *p; + int bit; - if (unlikely(!p) || kprobe_disabled(p)) + bit = ftrace_test_recursion_trylock(ip, parent_ip); + if (bit < 0) return; + regs = ftrace_get_regs(fregs); + preempt_disable_notrace(); + p = get_kprobe((kprobe_opcode_t *)ip); + if (unlikely(!p) || kprobe_disabled(p)) + goto out; + if (kprobe_running()) { kprobes_inc_nmissed_count(p); - return; + goto out; } __this_cpu_write(current_kprobe, p); @@ -235,6 +244,9 @@ void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip, } } __this_cpu_write(current_kprobe, NULL); +out: + preempt_enable_notrace(); + ftrace_test_recursion_unlock(bit); } NOKPROBE_SYMBOL(kprobe_ftrace_handler); diff --git a/arch/powerpc/include/asm/livepatch.h b/arch/powerpc/include/asm/livepatch.h index 4a3d5d25fed5..ae25e6e72997 100644 --- a/arch/powerpc/include/asm/livepatch.h +++ b/arch/powerpc/include/asm/livepatch.h @@ -12,8 +12,10 @@ #include <linux/sched/task_stack.h> #ifdef CONFIG_LIVEPATCH -static inline void klp_arch_set_pc(struct pt_regs *regs, unsigned long ip) +static inline void klp_arch_set_pc(struct ftrace_regs *fregs, unsigned long ip) { + struct pt_regs *regs = ftrace_get_regs(fregs); + regs->nip = ip; } diff --git a/arch/powerpc/kernel/kprobes-ftrace.c b/arch/powerpc/kernel/kprobes-ftrace.c index 972cb28174b2..660138f6c4b2 100644 --- a/arch/powerpc/kernel/kprobes-ftrace.c +++ b/arch/powerpc/kernel/kprobes-ftrace.c @@ -14,14 +14,22 @@ /* Ftrace callback handler for kprobes */ void kprobe_ftrace_handler(unsigned long nip, unsigned long parent_nip, - struct ftrace_ops *ops, struct pt_regs *regs) + struct ftrace_ops *ops, struct ftrace_regs *fregs) { struct kprobe *p; struct kprobe_ctlblk *kcb; + struct pt_regs *regs; + int bit; + bit = ftrace_test_recursion_trylock(nip, parent_nip); + if (bit < 0) + return; + + regs = ftrace_get_regs(fregs); + preempt_disable_notrace(); p = get_kprobe((kprobe_opcode_t *)nip); if (unlikely(!p) || kprobe_disabled(p)) - return; + goto out; kcb = get_kprobe_ctlblk(); if (kprobe_running()) { @@ -52,6 +60,9 @@ void kprobe_ftrace_handler(unsigned long nip, unsigned long parent_nip, */ __this_cpu_write(current_kprobe, NULL); } +out: + preempt_enable_notrace(); + ftrace_test_recursion_unlock(bit); } NOKPROBE_SYMBOL(kprobe_ftrace_handler); diff --git a/arch/s390/include/asm/livepatch.h b/arch/s390/include/asm/livepatch.h index 818612b784cd..d578a8c76676 100644 --- a/arch/s390/include/asm/livepatch.h +++ b/arch/s390/include/asm/livepatch.h @@ -11,10 +11,13 @@ #ifndef ASM_LIVEPATCH_H #define ASM_LIVEPATCH_H +#include <linux/ftrace.h> #include <asm/ptrace.h> -static inline void klp_arch_set_pc(struct pt_regs *regs, unsigned long ip) +static inline void klp_arch_set_pc(struct ftrace_regs *fregs, unsigned long ip) { + struct pt_regs *regs = ftrace_get_regs(fregs); + regs->psw.addr = ip; } diff --git a/arch/s390/kernel/ftrace.c b/arch/s390/kernel/ftrace.c index ebc1284a618b..c6ddeb5029b4 100644 --- a/arch/s390/kernel/ftrace.c +++ b/arch/s390/kernel/ftrace.c @@ -163,17 +163,26 @@ int ftrace_disable_ftrace_graph_caller(void) #ifdef CONFIG_KPROBES_ON_FTRACE void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip, - struct ftrace_ops *ops, struct pt_regs *regs) + struct ftrace_ops *ops, struct ftrace_regs *fregs) { struct kprobe_ctlblk *kcb; - struct kprobe *p = get_kprobe((kprobe_opcode_t *)ip); + struct pt_regs *regs; + struct kprobe *p; + int bit; - if (unlikely(!p) || kprobe_disabled(p)) + bit = ftrace_test_recursion_trylock(ip, parent_ip); + if (bit < 0) return; + regs = ftrace_get_regs(fregs); + preempt_disable_notrace(); + p = get_kprobe((kprobe_opcode_t *)ip); + if (unlikely(!p) || kprobe_disabled(p)) + goto out; + if (kprobe_running()) { kprobes_inc_nmissed_count(p); - return; + goto out; } __this_cpu_write(current_kprobe, p); @@ -193,6 +202,9 @@ void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip, } } __this_cpu_write(current_kprobe, NULL); +out: + preempt_enable_notrace(); + ftrace_test_recursion_unlock(bit); } NOKPROBE_SYMBOL(kprobe_ftrace_handler); diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index a8bd298e45b1..7b6dd10b162a 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -171,6 +171,7 @@ config X86 select HAVE_DMA_CONTIGUOUS select HAVE_DYNAMIC_FTRACE select HAVE_DYNAMIC_FTRACE_WITH_REGS + select HAVE_DYNAMIC_FTRACE_WITH_ARGS if X86_64 select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS select HAVE_EBPF_JIT select HAVE_EFFICIENT_UNALIGNED_ACCESS diff --git a/arch/x86/include/asm/ftrace.h b/arch/x86/include/asm/ftrace.h index 84b9449be080..9f3130f40807 100644 --- a/arch/x86/include/asm/ftrace.h +++ b/arch/x86/include/asm/ftrace.h @@ -41,6 +41,24 @@ static inline void arch_ftrace_set_direct_caller(struct pt_regs *regs, unsigned regs->orig_ax = addr; } +#ifdef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS +struct ftrace_regs { + struct pt_regs regs; +}; + +static __always_inline struct pt_regs * +arch_ftrace_get_regs(struct ftrace_regs *fregs) +{ + /* Only when FL_SAVE_REGS is set, cs will be non zero */ + if (!fregs->regs.cs) + return NULL; + return &fregs->regs; +} + +#define ftrace_instruction_pointer_set(fregs, _ip) \ + do { (fregs)->regs.ip = (_ip); } while (0) +#endif + #ifdef CONFIG_DYNAMIC_FTRACE struct dyn_arch_ftrace { diff --git a/arch/x86/include/asm/livepatch.h b/arch/x86/include/asm/livepatch.h index 1fde1ab6559e..7c5cc6660e4b 100644 --- a/arch/x86/include/asm/livepatch.h +++ b/arch/x86/include/asm/livepatch.h @@ -12,9 +12,9 @@ #include <asm/setup.h> #include <linux/ftrace.h> -static inline void klp_arch_set_pc(struct pt_regs *regs, unsigned long ip) +static inline void klp_arch_set_pc(struct ftrace_regs *fregs, unsigned long ip) { - regs->ip = ip; + ftrace_instruction_pointer_set(fregs, ip); } #endif /* _ASM_X86_LIVEPATCH_H */ diff --git a/arch/x86/kernel/ftrace_64.S b/arch/x86/kernel/ftrace_64.S index ac3d5f22fe64..0d54099c2a3a 100644 --- a/arch/x86/kernel/ftrace_64.S +++ b/arch/x86/kernel/ftrace_64.S @@ -140,16 +140,27 @@ SYM_FUNC_START(ftrace_caller) /* save_mcount_regs fills in first two parameters */ save_mcount_regs + /* Stack - skipping return address of ftrace_caller */ + leaq MCOUNT_REG_SIZE+8(%rsp), %rcx + movq %rcx, RSP(%rsp) + SYM_INNER_LABEL(ftrace_caller_op_ptr, SYM_L_GLOBAL) /* Load the ftrace_ops into the 3rd parameter */ movq function_trace_op(%rip), %rdx - /* regs go into 4th parameter (but make it NULL) */ - movq $0, %rcx + /* regs go into 4th parameter */ + leaq (%rsp), %rcx + + /* Only ops with REGS flag set should have CS register set */ + movq $0, CS(%rsp) SYM_INNER_LABEL(ftrace_call, SYM_L_GLOBAL) call ftrace_stub + /* Handlers can change the RIP */ + movq RIP(%rsp), %rax + movq %rax, MCOUNT_REG_SIZE(%rsp) + restore_mcount_regs /* diff --git a/arch/x86/kernel/kprobes/ftrace.c b/arch/x86/kernel/kprobes/ftrace.c index 681a4b36e9bb..373e5fa3ce1f 100644 --- a/arch/x86/kernel/kprobes/ftrace.c +++ b/arch/x86/kernel/kprobes/ftrace.c @@ -14,15 +14,21 @@ /* Ftrace callback handler for kprobes -- called under preepmt disabed */ void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip, - struct ftrace_ops *ops, struct pt_regs *regs) + struct ftrace_ops *ops, struct ftrace_regs *fregs) { + struct pt_regs *regs = ftrace_get_regs(fregs); struct kprobe *p; struct kprobe_ctlblk *kcb; + int bit; - /* Preempt is disabled by ftrace */ + bit = ftrace_test_recursion_trylock(ip, parent_ip); + if (bit < 0) + return; + + preempt_disable_notrace(); p = get_kprobe((kprobe_opcode_t *)ip); if (unlikely(!p) || kprobe_disabled(p)) - return; + goto out; kcb = get_kprobe_ctlblk(); if (kprobe_running()) { @@ -52,6 +58,9 @@ void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip, */ __this_cpu_write(current_kprobe, NULL); } +out: + preempt_enable_notrace(); + ftrace_test_recursion_unlock(bit); } NOKPROBE_SYMBOL(kprobe_ftrace_handler); diff --git a/fs/pstore/ftrace.c b/fs/pstore/ftrace.c index 5c0450701293..5939595f0115 100644 --- a/fs/pstore/ftrace.c +++ b/fs/pstore/ftrace.c @@ -26,8 +26,9 @@ static u64 pstore_ftrace_stamp; static void notrace pstore_ftrace_call(unsigned long ip, unsigned long parent_ip, struct ftrace_ops *op, - struct pt_regs *regs) + struct ftrace_regs *fregs) { + int bit; unsigned long flags; struct pstore_ftrace_record rec = {}; struct pstore_record record = { @@ -40,6 +41,10 @@ static void notrace pstore_ftrace_call(unsigned long ip, if (unlikely(oops_in_progress)) return; + bit = ftrace_test_recursion_trylock(ip, parent_ip); + if (bit < 0) + return; + local_irq_save(flags); rec.ip = ip; @@ -49,6 +54,7 @@ static void notrace pstore_ftrace_call(unsigned long ip, psinfo->write(&record); local_irq_restore(flags); + ftrace_test_recursion_unlock(bit); } static struct ftrace_ops pstore_ftrace_ops __read_mostly = { diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 1bd3a0356ae4..9a8ce28e4485 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -7,6 +7,7 @@ #ifndef _LINUX_FTRACE_H #define _LINUX_FTRACE_H +#include <linux/trace_recursion.h> #include <linux/trace_clock.h> #include <linux/kallsyms.h> #include <linux/linkage.h> @@ -89,15 +90,39 @@ ftrace_enable_sysctl(struct ctl_table *table, int write, struct ftrace_ops; +#ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS + +struct ftrace_regs { + struct pt_regs regs; +}; +#define arch_ftrace_get_regs(fregs) (&(fregs)->regs) + +/* + * ftrace_instruction_pointer_set() is to be defined by the architecture + * if to allow setting of the instruction pointer from the ftrace_regs + * when HAVE_DYNAMIC_FTRACE_WITH_ARGS is set and it supports + * live kernel patching. + */ +#define ftrace_instruction_pointer_set(fregs, ip) do { } while (0) +#endif /* CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS */ + +static __always_inline struct pt_regs *ftrace_get_regs(struct ftrace_regs *fregs) +{ + if (!fregs) + return NULL; + + return arch_ftrace_get_regs(fregs); +} + typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip, - struct ftrace_ops *op, struct pt_regs *regs); + struct ftrace_ops *op, struct ftrace_regs *fregs); ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops); /* * FTRACE_OPS_FL_* bits denote the state of ftrace_ops struct and are * set in the flags member. - * CONTROL, SAVE_REGS, SAVE_REGS_IF_SUPPORTED, RECURSION_SAFE, STUB and + * CONTROL, SAVE_REGS, SAVE_REGS_IF_SUPPORTED, RECURSION, STUB and * IPMODIFY are a kind of attribute flags which can be set only before * registering the ftrace_ops, and can not be modified while registered. * Changing those attribute flags after registering ftrace_ops will @@ -120,10 +145,10 @@ ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops); * passing regs to the handler. * Note, if this flag is set, the SAVE_REGS flag will automatically * get set upon registering the ftrace_ops, if the arch supports it. - * RECURSION_SAFE - The ftrace_ops can set this to tell the ftrace infrastructure - * that the call back has its own recursion protection. If it does - * not set this, then the ftrace infrastructure will add recursion - * protection for the caller. + * RECURSION - The ftrace_ops can set this to tell the ftrace infrastructure + * that the call back needs recursion protection. If it does + * not set this, then the ftrace infrastructure will assume + * that the callback can handle recursion on its own. * STUB - The ftrace_ops is just a place holder. * INITIALIZED - The ftrace_ops has already been initialized (first use time * register_ftrace_function() is called, it will initialized the ops) @@ -155,7 +180,7 @@ enum { FTRACE_OPS_FL_DYNAMIC = BIT(1), FTRACE_OPS_FL_SAVE_REGS = BIT(2), FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED = BIT(3), - FTRACE_OPS_FL_RECURSION_SAFE = BIT(4), + FTRACE_OPS_FL_RECURSION = BIT(4), FTRACE_OPS_FL_STUB = BIT(5), FTRACE_OPS_FL_INITIALIZED = BIT(6), FTRACE_OPS_FL_DELETED = BIT(7), @@ -258,7 +283,7 @@ int register_ftrace_function(struct ftrace_ops *ops); int unregister_ftrace_function(struct ftrace_ops *ops); extern void ftrace_stub(unsigned long a0, unsigned long a1, - struct ftrace_ops *op, struct pt_regs *regs); + struct ftrace_ops *op, struct ftrace_regs *fregs); #else /* !CONFIG_FUNCTION_TRACER */ /* @@ -863,11 +888,11 @@ struct ftrace_graph_ent { */ struct ftrace_graph_ret { unsigned long func; /* Current function */ + int depth; /* Number of functions that overran the depth limit for current task */ - unsigned long overrun; + unsigned int overrun; unsigned long long calltime; unsigned long long rettime; - int depth; } __packed; /* Type of the callback handlers for tracing function graph*/ diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h index a79404433812..b3a36b0cfc81 100644 --- a/include/linux/kprobes.h +++ b/include/linux/kprobes.h @@ -360,7 +360,7 @@ static inline void wait_for_kprobe_optimizer(void) { } #endif /* CONFIG_OPTPROBES */ #ifdef CONFIG_KPROBES_ON_FTRACE extern void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip, - struct ftrace_ops *ops, struct pt_regs *regs); + struct ftrace_ops *ops, struct ftrace_regs *fregs); extern int arch_prepare_kprobe_ftrace(struct kprobe *p); #endif diff --git a/include/linux/seq_buf.h b/include/linux/seq_buf.h index fb0205d87d3c..9d6c28cc4d8f 100644 --- a/include/linux/seq_buf.h +++ b/include/linux/seq_buf.h @@ -30,7 +30,7 @@ static inline void seq_buf_clear(struct seq_buf *s) } static inline void -seq_buf_init(struct seq_buf *s, unsigned char *buf, unsigned int size) +seq_buf_init(struct seq_buf *s, char *buf, unsigned int size) { s->buffer = buf; s->size = size; diff --git a/include/linux/trace_recursion.h b/include/linux/trace_recursion.h new file mode 100644 index 000000000000..a9f9c5714e65 --- /dev/null +++ b/include/linux/trace_recursion.h @@ -0,0 +1,232 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _LINUX_TRACE_RECURSION_H +#define _LINUX_TRACE_RECURSION_H + +#include <linux/interrupt.h> +#include <linux/sched.h> + +#ifdef CONFIG_TRACING + +/* Only current can touch trace_recursion */ + +/* + * For function tracing recursion: + * The order of these bits are important. + * + * When function tracing occurs, the following steps are made: + * If arch does not support a ftrace feature: + * call internal function (uses INTERNAL bits) which calls... + * If callback is registered to the "global" list, the list + * function is called and recursion checks the GLOBAL bits. + * then this function calls... + * The function callback, which can use the FTRACE bits to + * check for recursion. + * + * Now if the arch does not support a feature, and it calls + * the global list function which calls the ftrace callback + * all three of these steps will do a recursion protection. + * There's no reason to do one if the previous caller already + * did. The recursion that we are protecting against will + * go through the same steps again. + * + * To prevent the multiple recursion checks, if a recursion + * bit is set that is higher than the MAX bit of the current + * check, then we know that the check was made by the previous + * caller, and we can skip the current check. + */ +enum { + /* Function recursion bits */ + TRACE_FTRACE_BIT, + TRACE_FTRACE_NMI_BIT, + TRACE_FTRACE_IRQ_BIT, + TRACE_FTRACE_SIRQ_BIT, + + /* INTERNAL_BITs must be greater than FTRACE_BITs */ + TRACE_INTERNAL_BIT, + TRACE_INTERNAL_NMI_BIT, + TRACE_INTERNAL_IRQ_BIT, + TRACE_INTERNAL_SIRQ_BIT, + + TRACE_BRANCH_BIT, +/* + * Abuse of the trace_recursion. + * As we need a way to maintain state if we are tracing the function + * graph in irq because we want to trace a particular function that + * was called in irq context but we have irq tracing off. Since this + * can only be modified by current, we can reuse trace_recursion. + */ + TRACE_IRQ_BIT, + + /* Set if the function is in the set_graph_function file */ + TRACE_GRAPH_BIT, + + /* + * In the very unlikely case that an interrupt came in + * at a start of graph tracing, and we want to trace + * the function in that interrupt, the depth can be greater + * than zero, because of the preempted start of a previous + * trace. In an even more unlikely case, depth could be 2 + * if a softirq interrupted the start of graph tracing, + * followed by an interrupt preempting a start of graph + * tracing in the softirq, and depth can even be 3 + * if an NMI came in at the start of an interrupt function + * that preempted a softirq start of a function that + * preempted normal context!!!! Luckily, it can't be + * greater than 3, so the next two bits are a mask + * of what the depth is when we set TRACE_GRAPH_BIT + */ + + TRACE_GRAPH_DEPTH_START_BIT, + TRACE_GRAPH_DEPTH_END_BIT, + + /* + * To implement set_graph_notrace, if this bit is set, we ignore + * function graph tracing of called functions, until the return + * function is called to clear it. + */ + TRACE_GRAPH_NOTRACE_BIT, + + /* + * When transitioning between context, the preempt_count() may + * not be correct. Allow for a single recursion to cover this case. + */ + TRACE_TRANSITION_BIT, + + /* Used to prevent recursion recording from recursing. */ + TRACE_RECORD_RECURSION_BIT, +}; + +#define trace_recursion_set(bit) do { (current)->trace_recursion |= (1<<(bit)); } while (0) +#define trace_recursion_clear(bit) do { (current)->trace_recursion &= ~(1<<(bit)); } while (0) +#define trace_recursion_test(bit) ((current)->trace_recursion & (1<<(bit))) + +#define trace_recursion_depth() \ + (((current)->trace_recursion >> TRACE_GRAPH_DEPTH_START_BIT) & 3) +#define trace_recursion_set_depth(depth) \ + do { \ + current->trace_recursion &= \ + ~(3 << TRACE_GRAPH_DEPTH_START_BIT); \ + current->trace_recursion |= \ + ((depth) & 3) << TRACE_GRAPH_DEPTH_START_BIT; \ + } while (0) + +#define TRACE_CONTEXT_BITS 4 + +#define TRACE_FTRACE_START TRACE_FTRACE_BIT +#define TRACE_FTRACE_MAX ((1 << (TRACE_FTRACE_START + TRACE_CONTEXT_BITS)) - 1) + +#define TRACE_LIST_START TRACE_INTERNAL_BIT +#define TRACE_LIST_MAX ((1 << (TRACE_LIST_START + TRACE_CONTEXT_BITS)) - 1) + +#define TRACE_CONTEXT_MASK TRACE_LIST_MAX + +/* + * Used for setting context + * NMI = 0 + * IRQ = 1 + * SOFTIRQ = 2 + * NORMAL = 3 + */ +enum { + TRACE_CTX_NMI, + TRACE_CTX_IRQ, + TRACE_CTX_SOFTIRQ, + TRACE_CTX_NORMAL, +}; + +static __always_inline int trace_get_context_bit(void) +{ + unsigned long pc = preempt_count(); + + if (!(pc & (NMI_MASK | HARDIRQ_MASK | SOFTIRQ_OFFSET))) + return TRACE_CTX_NORMAL; + else + return pc & NMI_MASK ? TRACE_CTX_NMI : + pc & HARDIRQ_MASK ? TRACE_CTX_IRQ : TRACE_CTX_SOFTIRQ; +} + +#ifdef CONFIG_FTRACE_RECORD_RECURSION +extern void ftrace_record_recursion(unsigned long ip, unsigned long parent_ip); +# define do_ftrace_record_recursion(ip, pip) \ + do { \ + if (!trace_recursion_test(TRACE_RECORD_RECURSION_BIT)) { \ + trace_recursion_set(TRACE_RECORD_RECURSION_BIT); \ + ftrace_record_recursion(ip, pip); \ + trace_recursion_clear(TRACE_RECORD_RECURSION_BIT); \ + } \ + } while (0) +#else +# define do_ftrace_record_recursion(ip, pip) do { } while (0) +#endif + +static __always_inline int trace_test_and_set_recursion(unsigned long ip, unsigned long pip, + int start, int max) +{ + unsigned int val = READ_ONCE(current->trace_recursion); + int bit; + + /* A previous recursion check was made */ + if ((val & TRACE_CONTEXT_MASK) > max) + return 0; + + bit = trace_get_context_bit() + start; + if (unlikely(val & (1 << bit))) { + /* + * It could be that preempt_count has not been updated during + * a switch between contexts. Allow for a single recursion. + */ + bit = TRACE_TRANSITION_BIT; + if (val & (1 << bit)) { + do_ftrace_record_recursion(ip, pip); + return -1; + } + } else { + /* Normal check passed, clear the transition to allow it again */ + val &= ~(1 << TRACE_TRANSITION_BIT); + } + + val |= 1 << bit; + current->trace_recursion = val; + barrier(); + + return bit + 1; +} + +static __always_inline void trace_clear_recursion(int bit) +{ + if (!bit) + return; + + barrier(); + bit--; + trace_recursion_clear(bit); +} + +/** + * ftrace_test_recursion_trylock - tests for recursion in same context + * + * Use this for ftrace callbacks. This will detect if the function + * tracing recursed in the same context (normal vs interrupt), + * + * Returns: -1 if a recursion happened. + * >= 0 if no recursion + */ +static __always_inline int ftrace_test_recursion_trylock(unsigned long ip, + unsigned long parent_ip) +{ + return trace_test_and_set_recursion(ip, parent_ip, TRACE_FTRACE_START, TRACE_FTRACE_MAX); +} + +/** + * ftrace_test_recursion_unlock - called when function callback is complete + * @bit: The return of a successful ftrace_test_recursion_trylock() + * + * This is used at the end of a ftrace callback. + */ +static __always_inline void ftrace_test_recursion_unlock(int bit) +{ + trace_clear_recursion(bit); +} + +#endif /* CONFIG_TRACING */ +#endif /* _LINUX_TRACE_RECURSION_H */ diff --git a/include/linux/trace_seq.h b/include/linux/trace_seq.h index 6c30508fca19..5a2c650d9e1c 100644 --- a/include/linux/trace_seq.h +++ b/include/linux/trace_seq.h @@ -12,7 +12,7 @@ */ struct trace_seq { - unsigned char buffer[PAGE_SIZE]; + char buffer[PAGE_SIZE]; struct seq_buf seq; int full; }; @@ -51,7 +51,7 @@ static inline int trace_seq_used(struct trace_seq *s) * that is about to be written to and then return the result * of that write. */ -static inline unsigned char * +static inline char * trace_seq_buffer_ptr(struct trace_seq *s) { return s->buffer + seq_buf_used(&s->seq); diff --git a/kernel/livepatch/Kconfig b/kernel/livepatch/Kconfig index 54102deb50ba..53d51ed619a3 100644 --- a/kernel/livepatch/Kconfig +++ b/kernel/livepatch/Kconfig @@ -6,7 +6,7 @@ config HAVE_LIVEPATCH config LIVEPATCH bool "Kernel Live Patching" - depends on DYNAMIC_FTRACE_WITH_REGS + depends on DYNAMIC_FTRACE_WITH_REGS || DYNAMIC_FTRACE_WITH_ARGS depends on MODULES depends on SYSFS depends on KALLSYMS_ALL diff --git a/kernel/livepatch/patch.c b/kernel/livepatch/patch.c index b552cf2d85f8..e8029aea67f1 100644 --- a/kernel/livepatch/patch.c +++ b/kernel/livepatch/patch.c @@ -40,14 +40,18 @@ struct klp_ops *klp_find_ops(void *old_func) static void notrace klp_ftrace_handler(unsigned long ip, unsigned long parent_ip, struct ftrace_ops *fops, - struct pt_regs *regs) + struct ftrace_regs *fregs) { struct klp_ops *ops; struct klp_func *func; int patch_state; + int bit; ops = container_of(fops, struct klp_ops, fops); + bit = ftrace_test_recursion_trylock(ip, parent_ip); + if (WARN_ON_ONCE(bit < 0)) + return; /* * A variant of synchronize_rcu() is used to allow patching functions * where RCU is not watching, see klp_synchronize_transition(). @@ -113,10 +117,11 @@ static void notrace klp_ftrace_handler(unsigned long ip, if (func->nop) goto unlock; - klp_arch_set_pc(regs, (unsigned long)func->new_func); + klp_arch_set_pc(fregs, (unsigned long)func->new_func); unlock: preempt_enable_notrace(); + ftrace_test_recursion_unlock(bit); } /* @@ -194,8 +199,10 @@ static int klp_patch_func(struct klp_func *func) return -ENOMEM; ops->fops.func = klp_ftrace_handler; - ops->fops.flags = FTRACE_OPS_FL_SAVE_REGS | - FTRACE_OPS_FL_DYNAMIC | + ops->fops.flags = FTRACE_OPS_FL_DYNAMIC | +#ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS + FTRACE_OPS_FL_SAVE_REGS | +#endif FTRACE_OPS_FL_IPMODIFY | FTRACE_OPS_FL_PERMANENT; diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index 2f8d9cc42c40..d5a19413d4f8 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -31,6 +31,15 @@ config HAVE_DYNAMIC_FTRACE_WITH_REGS config HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS bool +config HAVE_DYNAMIC_FTRACE_WITH_ARGS + bool + help + If this is set, then arguments and stack can be found from + the pt_regs passed into the function callback regs parameter + by default, even without setting the REGS flag in the ftrace_ops. + This allows for use of regs_get_kernel_argument() and + kernel_stack_pointer(). + config HAVE_FTRACE_MCOUNT_RECORD bool help @@ -725,6 +734,45 @@ config TRACE_EVAL_MAP_FILE If unsure, say N. +config FTRACE_RECORD_RECURSION + bool "Record functions that recurse in function tracing" + depends on FUNCTION_TRACER + help + All callbacks that attach to the function tracing have some sort + of protection against recursion. Even though the protection exists, + it adds overhead. This option will create a file in the tracefs + file system called "recursed_functions" that will list the functions + that triggered a recursion. + + This will add more overhead to cases that have recursion. + + If unsure, say N + +config FTRACE_RECORD_RECURSION_SIZE + int "Max number of recursed functions to record" + default 128 + depends on FTRACE_RECORD_RECURSION + help + This defines the limit of number of functions that can be + listed in the "recursed_functions" file, that lists all + the functions that caused a recursion to happen. + This file can be reset, but the limit can not change in + size at runtime. + +config RING_BUFFER_RECORD_RECURSION + bool "Record functions that recurse in the ring buffer" + depends on FTRACE_RECORD_RECURSION + # default y, because it is coupled with FTRACE_RECORD_RECURSION + default y + help + The ring buffer has its own internal recursion. Although when + recursion happens it wont cause harm because of the protection, + but it does cause an unwanted overhead. Enabling this option will + place where recursion was detected into the ftrace "recursed_functions" + file. + + This will add more overhead to cases that have recursion. + config GCOV_PROFILE_FTRACE bool "Enable GCOV profiling on ftrace subsystem" depends on GCOV_KERNEL @@ -795,6 +843,26 @@ config RING_BUFFER_STARTUP_TEST If unsure, say N +config RING_BUFFER_VALIDATE_TIME_DELTAS + bool "Verify ring buffer time stamp deltas" + depends on RING_BUFFER + help + This will audit the time stamps on the ring buffer sub + buffer to make sure that all the time deltas for the + events on a sub buffer matches the current time stamp. + This audit is performed for every event that is not + interrupted, or interrupting another event. A check + is also made when traversing sub buffers to make sure + that all the deltas on the previous sub buffer do not + add up to be greater than the current time stamp. + + NOTE: This adds significant overhead to recording of events, + and should only be used to test the logic of the ring buffer. + Do not use it on production systems. + + Only say Y if you understand what this does, and you + still want it enabled. Otherwise say N + config MMIOTRACE_TEST tristate "Test module for mmiotrace" depends on MMIOTRACE && m diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile index e153be351548..7e44cea89fdc 100644 --- a/kernel/trace/Makefile +++ b/kernel/trace/Makefile @@ -92,6 +92,7 @@ obj-$(CONFIG_DYNAMIC_EVENTS) += trace_dynevent.o obj-$(CONFIG_PROBE_EVENTS) += trace_probe.o obj-$(CONFIG_UPROBE_EVENTS) += trace_uprobe.o obj-$(CONFIG_BOOTTIME_TRACING) += trace_boot.o +obj-$(CONFIG_FTRACE_RECORD_RECURSION) += trace_recursion_record.o obj-$(CONFIG_TRACEPOINT_BENCHMARK) += trace_benchmark.o diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c index 456fe4ce6942..fb0fe4c66b84 100644 --- a/kernel/trace/blktrace.c +++ b/kernel/trace/blktrace.c @@ -1279,7 +1279,7 @@ static void blk_log_action(struct trace_iterator *iter, const char *act, * ones now use the 64bit ino as the whole ID and * no longer use generation. * - * Regarldess of the content, always output + * Regardless of the content, always output * "LOW32,HIGH32" so that FILEID_INO32_GEN fid can * be mapped back to @id on both 64 and 32bit ino * setups. See __kernfs_fh_to_dentry(). @@ -1321,7 +1321,7 @@ static void blk_log_dump_pdu(struct trace_seq *s, i == 0 ? "" : " ", pdu_buf[i]); /* - * stop when the rest is just zeroes and indicate so + * stop when the rest is just zeros and indicate so * with a ".." appended */ if (i == end && end != pdu_len - 1) { diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index ebadaa83502c..6c0018abe68a 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -116,7 +116,7 @@ unsigned int trace_call_bpf(struct trace_event_call *call, void *ctx) * Instead of moving rcu_read_lock/rcu_dereference/rcu_read_unlock * to all call sites, we did a bpf_prog_array_valid() there to check * whether call->prog_array is empty or not, which is - * a heurisitc to speed up execution. + * a heuristic to speed up execution. * * If bpf_prog_array_valid() fetched prog_array was * non-NULL, we go into trace_call_bpf() and do the actual diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c index 5658f13037b3..73edb9e4f354 100644 --- a/kernel/trace/fgraph.c +++ b/kernel/trace/fgraph.c @@ -334,8 +334,7 @@ unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx, static struct ftrace_ops graph_ops = { .func = ftrace_stub, - .flags = FTRACE_OPS_FL_RECURSION_SAFE | - FTRACE_OPS_FL_INITIALIZED | + .flags = FTRACE_OPS_FL_INITIALIZED | FTRACE_OPS_FL_PID | FTRACE_OPS_FL_STUB, #ifdef FTRACE_GRAPH_TRAMP_ADDR diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 9c1bba8cc51b..4d8e35575549 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -80,7 +80,7 @@ enum { struct ftrace_ops ftrace_list_end __read_mostly = { .func = ftrace_stub, - .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_STUB, + .flags = FTRACE_OPS_FL_STUB, INIT_OPS_HASH(ftrace_list_end) }; @@ -121,7 +121,7 @@ struct ftrace_ops global_ops; #if ARCH_SUPPORTS_FTRACE_OPS static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip, - struct ftrace_ops *op, struct pt_regs *regs); + struct ftrace_ops *op, struct ftrace_regs *fregs); #else /* See comment below, where ftrace_ops_list_func is defined */ static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip); @@ -140,7 +140,7 @@ static inline void ftrace_ops_init(struct ftrace_ops *ops) } static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip, - struct ftrace_ops *op, struct pt_regs *regs) + struct ftrace_ops *op, struct ftrace_regs *fregs) { struct trace_array *tr = op->private; int pid; @@ -154,7 +154,7 @@ static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip, return; } - op->saved_func(ip, parent_ip, op, regs); + op->saved_func(ip, parent_ip, op, fregs); } static void ftrace_sync_ipi(void *data) @@ -754,7 +754,7 @@ ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip) static void function_profile_call(unsigned long ip, unsigned long parent_ip, - struct ftrace_ops *ops, struct pt_regs *regs) + struct ftrace_ops *ops, struct ftrace_regs *fregs) { struct ftrace_profile_stat *stat; struct ftrace_profile *rec; @@ -866,7 +866,7 @@ static void unregister_ftrace_profiler(void) #else static struct ftrace_ops ftrace_profile_ops __read_mostly = { .func = function_profile_call, - .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED, + .flags = FTRACE_OPS_FL_INITIALIZED, INIT_OPS_HASH(ftrace_profile_ops) }; @@ -1040,8 +1040,7 @@ struct ftrace_ops global_ops = { .local_hash.notrace_hash = EMPTY_HASH, .local_hash.filter_hash = EMPTY_HASH, INIT_OPS_HASH(global_ops) - .flags = FTRACE_OPS_FL_RECURSION_SAFE | - FTRACE_OPS_FL_INITIALIZED | + .flags = FTRACE_OPS_FL_INITIALIZED | FTRACE_OPS_FL_PID, }; @@ -2146,6 +2145,7 @@ static int ftrace_check_record(struct dyn_ftrace *rec, bool enable, bool update) else rec->flags &= ~FTRACE_FL_TRAMP_EN; } + if (flag & FTRACE_FL_DIRECT) { /* * If there's only one user (direct_ops helper) @@ -2389,8 +2389,9 @@ unsigned long ftrace_find_rec_direct(unsigned long ip) } static void call_direct_funcs(unsigned long ip, unsigned long pip, - struct ftrace_ops *ops, struct pt_regs *regs) + struct ftrace_ops *ops, struct ftrace_regs *fregs) { + struct pt_regs *regs = ftrace_get_regs(fregs); unsigned long addr; addr = ftrace_find_rec_direct(ip); @@ -2402,7 +2403,7 @@ static void call_direct_funcs(unsigned long ip, unsigned long pip, struct ftrace_ops direct_ops = { .func = call_direct_funcs, - .flags = FTRACE_OPS_FL_IPMODIFY | FTRACE_OPS_FL_RECURSION_SAFE + .flags = FTRACE_OPS_FL_IPMODIFY | FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_REGS | FTRACE_OPS_FL_PERMANENT, /* @@ -4183,7 +4184,6 @@ static void process_mod_list(struct list_head *head, struct ftrace_ops *ops, struct ftrace_hash **orig_hash, *new_hash; LIST_HEAD(process_mods); char *func; - int ret; mutex_lock(&ops->func_hash->regex_lock); @@ -4236,7 +4236,7 @@ static void process_mod_list(struct list_head *head, struct ftrace_ops *ops, mutex_lock(&ftrace_lock); - ret = ftrace_hash_move_and_update_ops(ops, orig_hash, + ftrace_hash_move_and_update_ops(ops, orig_hash, new_hash, enable); mutex_unlock(&ftrace_lock); @@ -4314,7 +4314,7 @@ static int __init ftrace_mod_cmd_init(void) core_initcall(ftrace_mod_cmd_init); static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip, - struct ftrace_ops *op, struct pt_regs *pt_regs) + struct ftrace_ops *op, struct ftrace_regs *fregs) { struct ftrace_probe_ops *probe_ops; struct ftrace_func_probe *probe; @@ -5588,7 +5588,6 @@ int ftrace_regex_release(struct inode *inode, struct file *file) struct ftrace_hash **orig_hash; struct trace_parser *parser; int filter_hash; - int ret; if (file->f_mode & FMODE_READ) { iter = m->private; @@ -5616,7 +5615,7 @@ int ftrace_regex_release(struct inode *inode, struct file *file) orig_hash = &iter->ops->func_hash->notrace_hash; mutex_lock(&ftrace_lock); - ret = ftrace_hash_move_and_update_ops(iter->ops, orig_hash, + ftrace_hash_move_and_update_ops(iter->ops, orig_hash, iter->hash, filter_hash); mutex_unlock(&ftrace_lock); } else { @@ -6884,8 +6883,7 @@ void ftrace_init_trace_array(struct trace_array *tr) struct ftrace_ops global_ops = { .func = ftrace_stub, - .flags = FTRACE_OPS_FL_RECURSION_SAFE | - FTRACE_OPS_FL_INITIALIZED | + .flags = FTRACE_OPS_FL_INITIALIZED | FTRACE_OPS_FL_PID, }; @@ -6935,12 +6933,13 @@ void ftrace_reset_array_ops(struct trace_array *tr) static nokprobe_inline void __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip, - struct ftrace_ops *ignored, struct pt_regs *regs) + struct ftrace_ops *ignored, struct ftrace_regs *fregs) { + struct pt_regs *regs = ftrace_get_regs(fregs); struct ftrace_ops *op; int bit; - bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX); + bit = trace_test_and_set_recursion(ip, parent_ip, TRACE_LIST_START, TRACE_LIST_MAX); if (bit < 0) return; @@ -6969,7 +6968,7 @@ __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip, pr_warn("op=%p %pS\n", op, op); goto out; } - op->func(ip, parent_ip, op, regs); + op->func(ip, parent_ip, op, fregs); } } while_for_each_ftrace_op(op); out: @@ -6992,9 +6991,9 @@ out: */ #if ARCH_SUPPORTS_FTRACE_OPS static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip, - struct ftrace_ops *op, struct pt_regs *regs) + struct ftrace_ops *op, struct ftrace_regs *fregs) { - __ftrace_ops_list_func(ip, parent_ip, NULL, regs); + __ftrace_ops_list_func(ip, parent_ip, NULL, fregs); } NOKPROBE_SYMBOL(ftrace_ops_list_func); #else @@ -7011,18 +7010,18 @@ NOKPROBE_SYMBOL(ftrace_ops_no_ops); * this function will be called by the mcount trampoline. */ static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip, - struct ftrace_ops *op, struct pt_regs *regs) + struct ftrace_ops *op, struct ftrace_regs *fregs) { int bit; - bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX); + bit = trace_test_and_set_recursion(ip, parent_ip, TRACE_LIST_START, TRACE_LIST_MAX); if (bit < 0) return; preempt_disable_notrace(); if (!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) - op->func(ip, parent_ip, op, regs); + op->func(ip, parent_ip, op, fregs); preempt_enable_notrace(); trace_clear_recursion(bit); @@ -7043,11 +7042,11 @@ NOKPROBE_SYMBOL(ftrace_ops_assist_func); ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops) { /* - * If the function does not handle recursion, needs to be RCU safe, - * or does per cpu logic, then we need to call the assist handler. + * If the function does not handle recursion or needs to be RCU safe, + * then we need to call the assist handler. */ - if (!(ops->flags & FTRACE_OPS_FL_RECURSION_SAFE) || - ops->flags & FTRACE_OPS_FL_RCU) + if (ops->flags & (FTRACE_OPS_FL_RECURSION | + FTRACE_OPS_FL_RCU)) return ftrace_ops_assist_func; return ops->func; diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index a6268e09160a..ec08f948dd80 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -4,6 +4,7 @@ * * Copyright (C) 2008 Steven Rostedt <srostedt@redhat.com> */ +#include <linux/trace_recursion.h> #include <linux/trace_events.h> #include <linux/ring_buffer.h> #include <linux/trace_clock.h> @@ -129,7 +130,16 @@ int ring_buffer_print_entry_header(struct trace_seq *s) #define RB_ALIGNMENT 4U #define RB_MAX_SMALL_DATA (RB_ALIGNMENT * RINGBUF_TYPE_DATA_TYPE_LEN_MAX) #define RB_EVNT_MIN_SIZE 8U /* two 32bit words */ -#define RB_ALIGN_DATA __aligned(RB_ALIGNMENT) + +#ifndef CONFIG_HAVE_64BIT_ALIGNED_ACCESS +# define RB_FORCE_8BYTE_ALIGNMENT 0 +# define RB_ARCH_ALIGNMENT RB_ALIGNMENT +#else +# define RB_FORCE_8BYTE_ALIGNMENT 1 +# define RB_ARCH_ALIGNMENT 8U +#endif + +#define RB_ALIGN_DATA __aligned(RB_ARCH_ALIGNMENT) /* define RINGBUF_TYPE_DATA for 'case RINGBUF_TYPE_DATA:' */ #define RINGBUF_TYPE_DATA 0 ... RINGBUF_TYPE_DATA_TYPE_LEN_MAX @@ -1422,7 +1432,8 @@ static int rb_check_pages(struct ring_buffer_per_cpu *cpu_buffer) return 0; } -static int __rb_allocate_pages(long nr_pages, struct list_head *pages, int cpu) +static int __rb_allocate_pages(struct ring_buffer_per_cpu *cpu_buffer, + long nr_pages, struct list_head *pages) { struct buffer_page *bpage, *tmp; bool user_thread = current->mm != NULL; @@ -1462,13 +1473,15 @@ static int __rb_allocate_pages(long nr_pages, struct list_head *pages, int cpu) struct page *page; bpage = kzalloc_node(ALIGN(sizeof(*bpage), cache_line_size()), - mflags, cpu_to_node(cpu)); + mflags, cpu_to_node(cpu_buffer->cpu)); if (!bpage) goto free_pages; + rb_check_bpage(cpu_buffer, bpage); + list_add(&bpage->list, pages); - page = alloc_pages_node(cpu_to_node(cpu), mflags, 0); + page = alloc_pages_node(cpu_to_node(cpu_buffer->cpu), mflags, 0); if (!page) goto free_pages; bpage->page = page_address(page); @@ -1500,7 +1513,7 @@ static int rb_allocate_pages(struct ring_buffer_per_cpu *cpu_buffer, WARN_ON(!nr_pages); - if (__rb_allocate_pages(nr_pages, &pages, cpu_buffer->cpu)) + if (__rb_allocate_pages(cpu_buffer, nr_pages, &pages)) return -ENOMEM; /* @@ -1973,8 +1986,6 @@ int ring_buffer_resize(struct trace_buffer *buffer, unsigned long size, if (nr_pages < 2) nr_pages = 2; - size = nr_pages * BUF_PAGE_SIZE; - /* prevent another thread from changing buffer sizes */ mutex_lock(&buffer->mutex); @@ -2009,8 +2020,8 @@ int ring_buffer_resize(struct trace_buffer *buffer, unsigned long size, * allocated without receiving ENOMEM */ INIT_LIST_HEAD(&cpu_buffer->new_pages); - if (__rb_allocate_pages(cpu_buffer->nr_pages_to_update, - &cpu_buffer->new_pages, cpu)) { + if (__rb_allocate_pages(cpu_buffer, cpu_buffer->nr_pages_to_update, + &cpu_buffer->new_pages)) { /* not enough memory for new pages */ err = -ENOMEM; goto out_err; @@ -2075,8 +2086,8 @@ int ring_buffer_resize(struct trace_buffer *buffer, unsigned long size, INIT_LIST_HEAD(&cpu_buffer->new_pages); if (cpu_buffer->nr_pages_to_update > 0 && - __rb_allocate_pages(cpu_buffer->nr_pages_to_update, - &cpu_buffer->new_pages, cpu_id)) { + __rb_allocate_pages(cpu_buffer, cpu_buffer->nr_pages_to_update, + &cpu_buffer->new_pages)) { err = -ENOMEM; goto out_err; } @@ -2628,9 +2639,6 @@ rb_add_time_stamp(struct ring_buffer_event *event, u64 delta, bool abs) return skip_time_extend(event); } -static inline bool rb_event_is_commit(struct ring_buffer_per_cpu *cpu_buffer, - struct ring_buffer_event *event); - #ifndef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK static inline bool sched_clock_stable(void) { @@ -2719,7 +2727,7 @@ rb_update_event(struct ring_buffer_per_cpu *cpu_buffer, event->time_delta = delta; length -= RB_EVNT_HDR_SIZE; - if (length > RB_MAX_SMALL_DATA) { + if (length > RB_MAX_SMALL_DATA || RB_FORCE_8BYTE_ALIGNMENT) { event->type_len = 0; event->array[0] = length; } else @@ -2734,11 +2742,11 @@ static unsigned rb_calculate_event_length(unsigned length) if (!length) length++; - if (length > RB_MAX_SMALL_DATA) + if (length > RB_MAX_SMALL_DATA || RB_FORCE_8BYTE_ALIGNMENT) length += sizeof(event.array[0]); length += RB_EVNT_HDR_SIZE; - length = ALIGN(length, RB_ALIGNMENT); + length = ALIGN(length, RB_ARCH_ALIGNMENT); /* * In case the time delta is larger than the 27 bits for it @@ -2758,20 +2766,6 @@ static unsigned rb_calculate_event_length(unsigned length) return length; } -static __always_inline bool -rb_event_is_commit(struct ring_buffer_per_cpu *cpu_buffer, - struct ring_buffer_event *event) -{ - unsigned long addr = (unsigned long)event; - unsigned long index; - - index = rb_event_index(event); - addr &= PAGE_MASK; - - return cpu_buffer->commit_page->page == (void *)addr && - rb_commit_index(cpu_buffer) == index; -} - static u64 rb_time_delta(struct ring_buffer_event *event) { switch (event->type_len) { @@ -3006,6 +3000,13 @@ rb_wakeups(struct trace_buffer *buffer, struct ring_buffer_per_cpu *cpu_buffer) irq_work_queue(&cpu_buffer->irq_work.work); } +#ifdef CONFIG_RING_BUFFER_RECORD_RECURSION +# define do_ring_buffer_record_recursion() \ + do_ftrace_record_recursion(_THIS_IP_, _RET_IP_) +#else +# define do_ring_buffer_record_recursion() do { } while (0) +#endif + /* * The lock and unlock are done within a preempt disable section. * The current_context per_cpu variable can only be modified @@ -3088,8 +3089,10 @@ trace_recursive_lock(struct ring_buffer_per_cpu *cpu_buffer) * been updated yet. In this case, use the TRANSITION bit. */ bit = RB_CTX_TRANSITION; - if (val & (1 << (bit + cpu_buffer->nest))) + if (val & (1 << (bit + cpu_buffer->nest))) { + do_ring_buffer_record_recursion(); return 1; + } } val |= (1 << (bit + cpu_buffer->nest)); @@ -3183,6 +3186,153 @@ int ring_buffer_unlock_commit(struct trace_buffer *buffer, } EXPORT_SYMBOL_GPL(ring_buffer_unlock_commit); +/* Special value to validate all deltas on a page. */ +#define CHECK_FULL_PAGE 1L + +#ifdef CONFIG_RING_BUFFER_VALIDATE_TIME_DELTAS +static void dump_buffer_page(struct buffer_data_page *bpage, + struct rb_event_info *info, + unsigned long tail) +{ + struct ring_buffer_event *event; + u64 ts, delta; + int e; + + ts = bpage->time_stamp; + pr_warn(" [%lld] PAGE TIME STAMP\n", ts); + + for (e = 0; e < tail; e += rb_event_length(event)) { + + event = (struct ring_buffer_event *)(bpage->data + e); + + switch (event->type_len) { + + case RINGBUF_TYPE_TIME_EXTEND: + delta = ring_buffer_event_time_stamp(event); + ts += delta; + pr_warn(" [%lld] delta:%lld TIME EXTEND\n", ts, delta); + break; + + case RINGBUF_TYPE_TIME_STAMP: + delta = ring_buffer_event_time_stamp(event); + ts = delta; + pr_warn(" [%lld] absolute:%lld TIME STAMP\n", ts, delta); + break; + + case RINGBUF_TYPE_PADDING: + ts += event->time_delta; + pr_warn(" [%lld] delta:%d PADDING\n", ts, event->time_delta); + break; + + case RINGBUF_TYPE_DATA: + ts += event->time_delta; + pr_warn(" [%lld] delta:%d\n", ts, event->time_delta); + break; + + default: + break; + } + } +} + +static DEFINE_PER_CPU(atomic_t, checking); +static atomic_t ts_dump; + +/* + * Check if the current event time stamp matches the deltas on + * the buffer page. + */ +static void check_buffer(struct ring_buffer_per_cpu *cpu_buffer, + struct rb_event_info *info, + unsigned long tail) +{ + struct ring_buffer_event *event; + struct buffer_data_page *bpage; + u64 ts, delta; + bool full = false; + int e; + + bpage = info->tail_page->page; + + if (tail == CHECK_FULL_PAGE) { + full = true; + tail = local_read(&bpage->commit); + } else if (info->add_timestamp & + (RB_ADD_STAMP_FORCE | RB_ADD_STAMP_ABSOLUTE)) { + /* Ignore events with absolute time stamps */ + return; + } + + /* + * Do not check the first event (skip possible extends too). + * Also do not check if previous events have not been committed. + */ + if (tail <= 8 || tail > local_read(&bpage->commit)) + return; + + /* + * If this interrupted another event, + */ + if (atomic_inc_return(this_cpu_ptr(&checking)) != 1) + goto out; + + ts = bpage->time_stamp; + + for (e = 0; e < tail; e += rb_event_length(event)) { + + event = (struct ring_buffer_event *)(bpage->data + e); + + switch (event->type_len) { + + case RINGBUF_TYPE_TIME_EXTEND: + delta = ring_buffer_event_time_stamp(event); + ts += delta; + break; + + case RINGBUF_TYPE_TIME_STAMP: + delta = ring_buffer_event_time_stamp(event); + ts = delta; + break; + + case RINGBUF_TYPE_PADDING: + if (event->time_delta == 1) + break; + /* fall through */ + case RINGBUF_TYPE_DATA: + ts += event->time_delta; + break; + + default: + RB_WARN_ON(cpu_buffer, 1); + } + } + if ((full && ts > info->ts) || + (!full && ts + info->delta != info->ts)) { + /* If another report is happening, ignore this one */ + if (atomic_inc_return(&ts_dump) != 1) { + atomic_dec(&ts_dump); + goto out; + } + atomic_inc(&cpu_buffer->record_disabled); + pr_warn("[CPU: %d]TIME DOES NOT MATCH expected:%lld actual:%lld delta:%lld after:%lld\n", + cpu_buffer->cpu, + ts + info->delta, info->ts, info->delta, info->after); + dump_buffer_page(bpage, info, tail); + atomic_dec(&ts_dump); + /* Do not re-enable checking */ + return; + } +out: + atomic_dec(this_cpu_ptr(&checking)); +} +#else +static inline void check_buffer(struct ring_buffer_per_cpu *cpu_buffer, + struct rb_event_info *info, + unsigned long tail) +{ +} +#endif /* CONFIG_RING_BUFFER_VALIDATE_TIME_DELTAS */ + static struct ring_buffer_event * __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer, struct rb_event_info *info) @@ -3240,6 +3390,8 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer, if (a_ok && b_ok && info->before != info->after) (void)rb_time_cmpxchg(&cpu_buffer->before_stamp, info->before, info->after); + if (a_ok && b_ok) + check_buffer(cpu_buffer, info, CHECK_FULL_PAGE); return rb_move_tail(cpu_buffer, tail, info); } @@ -3257,9 +3409,10 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer, /* This did not interrupt any time update */ info->delta = info->ts - info->after; else - /* Just use full timestamp for inerrupting event */ + /* Just use full timestamp for interrupting event */ info->delta = info->ts; barrier(); + check_buffer(cpu_buffer, info, tail); if (unlikely(info->ts != save_before)) { /* SLOW PATH - Interrupted between C and E */ @@ -3293,7 +3446,7 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer, info->ts = ts; } else { /* - * Interrupted beween C and E: + * Interrupted between C and E: * Lost the previous events time stamp. Just set the * delta to zero, and this will be the same time as * the event this event interrupted. And the events that @@ -3500,7 +3653,7 @@ rb_decrement_entry(struct ring_buffer_per_cpu *cpu_buffer, } /** - * ring_buffer_commit_discard - discard an event that has not been committed + * ring_buffer_discard_commit - discard an event that has not been committed * @buffer: the ring buffer * @event: non committed event to discard * diff --git a/kernel/trace/synth_event_gen_test.c b/kernel/trace/synth_event_gen_test.c index edd912cd14aa..a4b4bbf8c3bf 100644 --- a/kernel/trace/synth_event_gen_test.c +++ b/kernel/trace/synth_event_gen_test.c @@ -307,7 +307,7 @@ static int __init test_create_synth_event(void) return ret; delete: /* We got an error after creating the event, delete it */ - ret = synth_event_delete("create_synth_test"); + synth_event_delete("create_synth_test"); goto out; } diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 06134189e9a7..b8a2d786b503 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -68,10 +68,21 @@ bool ring_buffer_expanded; static bool __read_mostly tracing_selftest_running; /* - * If a tracer is running, we do not want to run SELFTEST. + * If boot-time tracing including tracers/events via kernel cmdline + * is running, we do not want to run SELFTEST. */ bool __read_mostly tracing_selftest_disabled; +#ifdef CONFIG_FTRACE_STARTUP_TEST +void __init disable_tracing_selftest(const char *reason) +{ + if (!tracing_selftest_disabled) { + tracing_selftest_disabled = true; + pr_info("Ftrace startup test is disabled due to %s\n", reason); + } +} +#endif + /* Pipe tracepoints to printk */ struct trace_iterator *tracepoint_print_iter; int tracepoint_printk; @@ -2113,11 +2124,7 @@ int __init register_tracer(struct tracer *type) apply_trace_boot_options(); /* disable other selftests, since this will break it. */ - tracing_selftest_disabled = true; -#ifdef CONFIG_FTRACE_STARTUP_TEST - printk(KERN_INFO "Disabling FTRACE selftests due to running tracer '%s'\n", - type->name); -#endif + disable_tracing_selftest("running a tracer"); out_unlock: return ret; @@ -3121,7 +3128,7 @@ struct trace_buffer_struct { static struct trace_buffer_struct *trace_percpu_buffer; /* - * Thise allows for lockless recording. If we're nested too deeply, then + * This allows for lockless recording. If we're nested too deeply, then * this returns NULL. */ static char *get_trace_buf(void) @@ -9062,7 +9069,10 @@ int tracing_init_dentry(void) extern struct trace_eval_map *__start_ftrace_eval_maps[]; extern struct trace_eval_map *__stop_ftrace_eval_maps[]; -static void __init trace_eval_init(void) +static struct workqueue_struct *eval_map_wq __initdata; +static struct work_struct eval_map_work __initdata; + +static void __init eval_map_work_func(struct work_struct *work) { int len; @@ -9070,6 +9080,33 @@ static void __init trace_eval_init(void) trace_insert_eval_map(NULL, __start_ftrace_eval_maps, len); } +static int __init trace_eval_init(void) +{ + INIT_WORK(&eval_map_work, eval_map_work_func); + + eval_map_wq = alloc_workqueue("eval_map_wq", WQ_UNBOUND, 0); + if (!eval_map_wq) { + pr_err("Unable to allocate eval_map_wq\n"); + /* Do work here */ + eval_map_work_func(&eval_map_work); + return -ENOMEM; + } + + queue_work(eval_map_wq, &eval_map_work); + return 0; +} + +static int __init trace_eval_sync(void) +{ + /* Make sure the eval map updates are finished */ + if (eval_map_wq) + destroy_workqueue(eval_map_wq); + return 0; +} + +late_initcall_sync(trace_eval_sync); + + #ifdef CONFIG_MODULES static void trace_module_add_evals(struct module *mod) { diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 1dadef445cd1..e448d2da0b99 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -558,183 +558,6 @@ struct tracer { bool noboot; }; - -/* Only current can touch trace_recursion */ - -/* - * For function tracing recursion: - * The order of these bits are important. - * - * When function tracing occurs, the following steps are made: - * If arch does not support a ftrace feature: - * call internal function (uses INTERNAL bits) which calls... - * If callback is registered to the "global" list, the list - * function is called and recursion checks the GLOBAL bits. - * then this function calls... - * The function callback, which can use the FTRACE bits to - * check for recursion. - * - * Now if the arch does not support a feature, and it calls - * the global list function which calls the ftrace callback - * all three of these steps will do a recursion protection. - * There's no reason to do one if the previous caller already - * did. The recursion that we are protecting against will - * go through the same steps again. - * - * To prevent the multiple recursion checks, if a recursion - * bit is set that is higher than the MAX bit of the current - * check, then we know that the check was made by the previous - * caller, and we can skip the current check. - */ -enum { - /* Function recursion bits */ - TRACE_FTRACE_BIT, - TRACE_FTRACE_NMI_BIT, - TRACE_FTRACE_IRQ_BIT, - TRACE_FTRACE_SIRQ_BIT, - - /* INTERNAL_BITs must be greater than FTRACE_BITs */ - TRACE_INTERNAL_BIT, - TRACE_INTERNAL_NMI_BIT, - TRACE_INTERNAL_IRQ_BIT, - TRACE_INTERNAL_SIRQ_BIT, - - TRACE_BRANCH_BIT, -/* - * Abuse of the trace_recursion. - * As we need a way to maintain state if we are tracing the function - * graph in irq because we want to trace a particular function that - * was called in irq context but we have irq tracing off. Since this - * can only be modified by current, we can reuse trace_recursion. - */ - TRACE_IRQ_BIT, - - /* Set if the function is in the set_graph_function file */ - TRACE_GRAPH_BIT, - - /* - * In the very unlikely case that an interrupt came in - * at a start of graph tracing, and we want to trace - * the function in that interrupt, the depth can be greater - * than zero, because of the preempted start of a previous - * trace. In an even more unlikely case, depth could be 2 - * if a softirq interrupted the start of graph tracing, - * followed by an interrupt preempting a start of graph - * tracing in the softirq, and depth can even be 3 - * if an NMI came in at the start of an interrupt function - * that preempted a softirq start of a function that - * preempted normal context!!!! Luckily, it can't be - * greater than 3, so the next two bits are a mask - * of what the depth is when we set TRACE_GRAPH_BIT - */ - - TRACE_GRAPH_DEPTH_START_BIT, - TRACE_GRAPH_DEPTH_END_BIT, - - /* - * To implement set_graph_notrace, if this bit is set, we ignore - * function graph tracing of called functions, until the return - * function is called to clear it. - */ - TRACE_GRAPH_NOTRACE_BIT, - - /* - * When transitioning between context, the preempt_count() may - * not be correct. Allow for a single recursion to cover this case. - */ - TRACE_TRANSITION_BIT, -}; - -#define trace_recursion_set(bit) do { (current)->trace_recursion |= (1<<(bit)); } while (0) -#define trace_recursion_clear(bit) do { (current)->trace_recursion &= ~(1<<(bit)); } while (0) -#define trace_recursion_test(bit) ((current)->trace_recursion & (1<<(bit))) - -#define trace_recursion_depth() \ - (((current)->trace_recursion >> TRACE_GRAPH_DEPTH_START_BIT) & 3) -#define trace_recursion_set_depth(depth) \ - do { \ - current->trace_recursion &= \ - ~(3 << TRACE_GRAPH_DEPTH_START_BIT); \ - current->trace_recursion |= \ - ((depth) & 3) << TRACE_GRAPH_DEPTH_START_BIT; \ - } while (0) - -#define TRACE_CONTEXT_BITS 4 - -#define TRACE_FTRACE_START TRACE_FTRACE_BIT -#define TRACE_FTRACE_MAX ((1 << (TRACE_FTRACE_START + TRACE_CONTEXT_BITS)) - 1) - -#define TRACE_LIST_START TRACE_INTERNAL_BIT -#define TRACE_LIST_MAX ((1 << (TRACE_LIST_START + TRACE_CONTEXT_BITS)) - 1) - -#define TRACE_CONTEXT_MASK TRACE_LIST_MAX - -static __always_inline int trace_get_context_bit(void) -{ - int bit; - - if (in_interrupt()) { - if (in_nmi()) - bit = 0; - - else if (in_irq()) - bit = 1; - else - bit = 2; - } else - bit = 3; - - return bit; -} - -static __always_inline int trace_test_and_set_recursion(int start, int max) -{ - unsigned int val = current->trace_recursion; - int bit; - - /* A previous recursion check was made */ - if ((val & TRACE_CONTEXT_MASK) > max) - return 0; - - bit = trace_get_context_bit() + start; - if (unlikely(val & (1 << bit))) { - /* - * It could be that preempt_count has not been updated during - * a switch between contexts. Allow for a single recursion. - */ - bit = TRACE_TRANSITION_BIT; - if (trace_recursion_test(bit)) - return -1; - trace_recursion_set(bit); - barrier(); - return bit + 1; - } - - /* Normal check passed, clear the transition to allow it again */ - trace_recursion_clear(TRACE_TRANSITION_BIT); - - val |= 1 << bit; - current->trace_recursion = val; - barrier(); - - return bit + 1; -} - -static __always_inline void trace_clear_recursion(int bit) -{ - unsigned int val = current->trace_recursion; - - if (!bit) - return; - - bit--; - bit = 1 << bit; - val &= ~bit; - - barrier(); - current->trace_recursion = val; -} - static inline struct ring_buffer_iter * trace_buffer_iter(struct trace_iterator *iter, int cpu) { @@ -896,6 +719,8 @@ extern bool ring_buffer_expanded; extern bool tracing_selftest_disabled; #ifdef CONFIG_FTRACE_STARTUP_TEST +extern void __init disable_tracing_selftest(const char *reason); + extern int trace_selftest_startup_function(struct tracer *trace, struct trace_array *tr); extern int trace_selftest_startup_function_graph(struct tracer *trace, @@ -919,6 +744,9 @@ extern int trace_selftest_startup_branch(struct tracer *trace, */ #define __tracer_data __refdata #else +static inline void __init disable_tracing_selftest(const char *reason) +{ +} /* Tracers are seldom changed. Optimize when selftests are disabled. */ #define __tracer_data __read_mostly #endif /* CONFIG_FTRACE_STARTUP_TEST */ diff --git a/kernel/trace/trace_benchmark.c b/kernel/trace/trace_benchmark.c index 2e9a4746ea85..801c2a7f7605 100644 --- a/kernel/trace/trace_benchmark.c +++ b/kernel/trace/trace_benchmark.c @@ -31,7 +31,7 @@ static bool ok_to_run; * it simply writes "START". As the first write is cold cache and * the rest is hot, we save off that time in bm_first and it is * reported as "first", which is shown in the second write to the - * tracepoint. The "first" field is writen within the statics from + * tracepoint. The "first" field is written within the statics from * then on but never changes. */ static void trace_do_benchmark(void) @@ -112,7 +112,7 @@ static void trace_do_benchmark(void) int i = 0; /* * stddev is the square of standard deviation but - * we want the actualy number. Use the average + * we want the actually number. Use the average * as our seed to find the std. * * The next try is: @@ -155,7 +155,7 @@ static int benchmark_event_kthread(void *arg) /* * We don't go to sleep, but let others run as well. - * This is bascially a "yield()" to let any task that + * This is basically a "yield()" to let any task that * wants to run, schedule in, but if the CPU is idle, * we'll keep burning cycles. * diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c index c22a152ef0b4..a82f03f385f8 100644 --- a/kernel/trace/trace_boot.c +++ b/kernel/trace/trace_boot.c @@ -344,6 +344,8 @@ static int __init trace_boot_init(void) trace_boot_init_one_instance(tr, trace_node); trace_boot_init_instances(trace_node); + disable_tracing_selftest("running boot-time tracing"); + return 0; } /* diff --git a/kernel/trace/trace_dynevent.c b/kernel/trace/trace_dynevent.c index 5fa49cfd2bb6..4f967d5cd917 100644 --- a/kernel/trace/trace_dynevent.c +++ b/kernel/trace/trace_dynevent.c @@ -276,7 +276,7 @@ int dynevent_arg_add(struct dynevent_cmd *cmd, * arguments of the form 'type variable_name;' or 'x+y'. * * The lhs argument string will be appended to the current cmd string, - * followed by an operator, if applicable, followd by the rhs string, + * followed by an operator, if applicable, followed by the rhs string, * followed finally by a separator, if applicable. Before the * argument is added, the @check_arg function, if present, will be * used to check the sanity of the current arg strings. diff --git a/kernel/trace/trace_dynevent.h b/kernel/trace/trace_dynevent.h index d6857a254ede..d6f72dcb7269 100644 --- a/kernel/trace/trace_dynevent.h +++ b/kernel/trace/trace_dynevent.h @@ -29,10 +29,10 @@ struct dyn_event; * @show: Showing method. This is invoked when user reads the event definitions * via dynamic_events interface. * @is_busy: Check whether given event is busy so that it can not be deleted. - * Return true if it is busy, otherwides false. - * @free: Delete the given event. Return 0 if success, otherwides error. + * Return true if it is busy, otherwise false. + * @free: Delete the given event. Return 0 if success, otherwise error. * @match: Check whether given event and system name match this event. The argc - * and argv is used for exact match. Return true if it matches, otherwides + * and argv is used for exact match. Return true if it matches, otherwise * false. * * Except for @create, these methods are called under holding event_mutex. diff --git a/kernel/trace/trace_entries.h b/kernel/trace/trace_entries.h index 18c4a58aff79..4547ac59da61 100644 --- a/kernel/trace/trace_entries.h +++ b/kernel/trace/trace_entries.h @@ -32,7 +32,7 @@ * to be deciphered for the format file. Although these macros * may become out of sync with the internal structure, they * will create a compile error if it happens. Since the - * internel structures are just tracing helpers, this is not + * internal structures are just tracing helpers, this is not * an issue. * * When an internal structure is used, it should use: @@ -93,10 +93,10 @@ FTRACE_ENTRY_PACKED(funcgraph_exit, ftrace_graph_ret_entry, F_STRUCT( __field_struct( struct ftrace_graph_ret, ret ) __field_packed( unsigned long, ret, func ) - __field_packed( unsigned long, ret, overrun ) + __field_packed( int, ret, depth ) + __field_packed( unsigned int, ret, overrun ) __field_packed( unsigned long long, ret, calltime) __field_packed( unsigned long long, ret, rettime ) - __field_packed( int, ret, depth ) ), F_printk("<-- %ps (%d) (start: %llx end: %llx) over: %d", diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c index 643e0b19920d..a71181655958 100644 --- a/kernel/trace/trace_event_perf.c +++ b/kernel/trace/trace_event_perf.c @@ -432,17 +432,25 @@ NOKPROBE_SYMBOL(perf_trace_buf_update); #ifdef CONFIG_FUNCTION_TRACER static void perf_ftrace_function_call(unsigned long ip, unsigned long parent_ip, - struct ftrace_ops *ops, struct pt_regs *pt_regs) + struct ftrace_ops *ops, struct ftrace_regs *fregs) { struct ftrace_entry *entry; struct perf_event *event; struct hlist_head head; struct pt_regs regs; int rctx; + int bit; + + if (!rcu_is_watching()) + return; if ((unsigned long)ops->private != smp_processor_id()) return; + bit = ftrace_test_recursion_trylock(ip, parent_ip); + if (bit < 0) + return; + event = container_of(ops, struct perf_event, ftrace_ops); /* @@ -463,13 +471,15 @@ perf_ftrace_function_call(unsigned long ip, unsigned long parent_ip, entry = perf_trace_buf_alloc(ENTRY_SIZE, NULL, &rctx); if (!entry) - return; + goto out; entry->ip = ip; entry->parent_ip = parent_ip; perf_trace_buf_submit(entry, ENTRY_SIZE, rctx, TRACE_FN, 1, ®s, &head, NULL); +out: + ftrace_test_recursion_unlock(bit); #undef ENTRY_SIZE } @@ -477,7 +487,6 @@ static int perf_ftrace_function_register(struct perf_event *event) { struct ftrace_ops *ops = &event->ftrace_ops; - ops->flags = FTRACE_OPS_FL_RCU; ops->func = perf_ftrace_function_call; ops->private = (void *)(unsigned long)nr_cpu_ids; diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index adf65b502453..e9d28eeccb7e 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -2436,7 +2436,7 @@ void trace_event_eval_update(struct trace_eval_map **map, int len) /* * Since calls are grouped by systems, the likelyhood that the * next call in the iteration belongs to the same system as the - * previous call is high. As an optimization, we skip seaching + * previous call is high. As an optimization, we skip searching * for a map[] that matches the call's system if the last call * was from the same system. That's what last_i is for. If the * call has the same system as the previous call, then last_i @@ -3201,7 +3201,7 @@ static __init int setup_trace_event(char *str) { strlcpy(bootup_event_buf, str, COMMAND_LINE_SIZE); ring_buffer_expanded = true; - tracing_selftest_disabled = true; + disable_tracing_selftest("running event tracing"); return 1; } @@ -3271,7 +3271,7 @@ create_event_toplevel_files(struct dentry *parent, struct trace_array *tr) * * When a new instance is created, it needs to set up its events * directory, as well as other files associated with events. It also - * creates the event hierachry in the @parent/events directory. + * creates the event hierarchy in the @parent/events directory. * * Returns 0 on success. * @@ -3673,7 +3673,7 @@ static struct trace_event_file event_trace_file __initdata; static void __init function_test_events_call(unsigned long ip, unsigned long parent_ip, - struct ftrace_ops *op, struct pt_regs *pt_regs) + struct ftrace_ops *op, struct ftrace_regs *regs) { struct trace_buffer *buffer; struct ring_buffer_event *event; @@ -3712,7 +3712,6 @@ function_test_events_call(unsigned long ip, unsigned long parent_ip, static struct ftrace_ops trace_ops __initdata = { .func = function_test_events_call, - .flags = FTRACE_OPS_FL_RECURSION_SAFE, }; static __init void event_trace_self_test_with_function(void) diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c index 78a678eeb140..e91259f6a722 100644 --- a/kernel/trace/trace_events_filter.c +++ b/kernel/trace/trace_events_filter.c @@ -1561,27 +1561,6 @@ static inline void event_clear_filter(struct trace_event_file *file) RCU_INIT_POINTER(file->filter, NULL); } -static inline void -event_set_no_set_filter_flag(struct trace_event_file *file) -{ - file->flags |= EVENT_FILE_FL_NO_SET_FILTER; -} - -static inline void -event_clear_no_set_filter_flag(struct trace_event_file *file) -{ - file->flags &= ~EVENT_FILE_FL_NO_SET_FILTER; -} - -static inline bool -event_no_set_filter_flag(struct trace_event_file *file) -{ - if (file->flags & EVENT_FILE_FL_NO_SET_FILTER) - return true; - - return false; -} - struct filter_list { struct list_head list; struct event_filter *filter; @@ -1950,7 +1929,7 @@ static int __ftrace_function_set_filter(int filter, char *buf, int len, /* * The 'ip' field could have multiple filters set, separated * either by space or comma. We first cut the filter and apply - * all pieces separatelly. + * all pieces separately. */ re = ftrace_function_filter_re(buf, len, &re_cnt); if (!re) diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index 96c3f86b81c5..39ebe1826fc3 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -3355,7 +3355,7 @@ trace_action_create_field_var(struct hist_trigger_data *hist_data, } else { field_var = NULL; /* - * If no explicit system.event is specfied, default to + * If no explicit system.event is specified, default to * looking for fields on the onmatch(system.event.xxx) * event. */ diff --git a/kernel/trace/trace_events_synth.c b/kernel/trace/trace_events_synth.c index 881df991742a..5a8bc0b421f1 100644 --- a/kernel/trace/trace_events_synth.c +++ b/kernel/trace/trace_events_synth.c @@ -1276,7 +1276,7 @@ static int __create_synth_event(int argc, const char *name, const char **argv) /** * synth_event_create - Create a new synthetic event - * @name: The name of the new sythetic event + * @name: The name of the new synthetic event * @fields: An array of type/name field descriptions * @n_fields: The number of field descriptions contained in the fields array * @mod: The module creating the event, NULL if not created from a module @@ -1446,7 +1446,7 @@ __synth_event_trace_init(struct trace_event_file *file, * this code to be called, etc). Because this is called * directly by the user, we don't have that but we still need * to honor not logging when disabled. For the iterated - * trace case, we save the enabed state upon start and just + * trace case, we save the enabled state upon start and just * ignore the following data calls. */ if (!(file->flags & EVENT_FILE_FL_ENABLED) || diff --git a/kernel/trace/trace_export.c b/kernel/trace/trace_export.c index 90f81d33fa3f..d960f6b11b5e 100644 --- a/kernel/trace/trace_export.c +++ b/kernel/trace/trace_export.c @@ -26,7 +26,7 @@ static int ftrace_event_register(struct trace_event_call *call, /* * The FTRACE_ENTRY_REG macro allows ftrace entry to define register - * function and thus become accesible via perf. + * function and thus become accessible via perf. */ #undef FTRACE_ENTRY_REG #define FTRACE_ENTRY_REG(name, struct_name, id, tstruct, print, regfn) \ diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c index 2c2126e1871d..c5095dd28e20 100644 --- a/kernel/trace/trace_functions.c +++ b/kernel/trace/trace_functions.c @@ -23,10 +23,10 @@ static void tracing_start_function_trace(struct trace_array *tr); static void tracing_stop_function_trace(struct trace_array *tr); static void function_trace_call(unsigned long ip, unsigned long parent_ip, - struct ftrace_ops *op, struct pt_regs *pt_regs); + struct ftrace_ops *op, struct ftrace_regs *fregs); static void function_stack_trace_call(unsigned long ip, unsigned long parent_ip, - struct ftrace_ops *op, struct pt_regs *pt_regs); + struct ftrace_ops *op, struct ftrace_regs *fregs); static struct tracer_flags func_flags; /* Our option */ @@ -48,7 +48,7 @@ int ftrace_allocate_ftrace_ops(struct trace_array *tr) /* Currently only the non stack version is supported */ ops->func = function_trace_call; - ops->flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_PID; + ops->flags = FTRACE_OPS_FL_PID; tr->ops = ops; ops->private = tr; @@ -89,7 +89,6 @@ void ftrace_destroy_function_files(struct trace_array *tr) static int function_trace_init(struct trace_array *tr) { ftrace_func_t func; - /* * Instance trace_arrays get their ops allocated * at instance creation. Unless it failed @@ -129,7 +128,7 @@ static void function_trace_start(struct trace_array *tr) static void function_trace_call(unsigned long ip, unsigned long parent_ip, - struct ftrace_ops *op, struct pt_regs *pt_regs) + struct ftrace_ops *op, struct ftrace_regs *fregs) { struct trace_array *tr = op->private; struct trace_array_cpu *data; @@ -141,22 +140,20 @@ function_trace_call(unsigned long ip, unsigned long parent_ip, if (unlikely(!tr->function_enabled)) return; + bit = ftrace_test_recursion_trylock(ip, parent_ip); + if (bit < 0) + return; + pc = preempt_count(); preempt_disable_notrace(); - bit = trace_test_and_set_recursion(TRACE_FTRACE_START, TRACE_FTRACE_MAX); - if (bit < 0) - goto out; - cpu = smp_processor_id(); data = per_cpu_ptr(tr->array_buffer.data, cpu); if (!atomic_read(&data->disabled)) { local_save_flags(flags); trace_function(tr, ip, parent_ip, flags, pc); } - trace_clear_recursion(bit); - - out: + ftrace_test_recursion_unlock(bit); preempt_enable_notrace(); } @@ -180,7 +177,7 @@ function_trace_call(unsigned long ip, unsigned long parent_ip, static void function_stack_trace_call(unsigned long ip, unsigned long parent_ip, - struct ftrace_ops *op, struct pt_regs *pt_regs) + struct ftrace_ops *op, struct ftrace_regs *fregs) { struct trace_array *tr = op->private; struct trace_array_cpu *data; diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c index 60d66278aa0d..d874dec87131 100644 --- a/kernel/trace/trace_functions_graph.c +++ b/kernel/trace/trace_functions_graph.c @@ -957,7 +957,7 @@ print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s, /* Overrun */ if (flags & TRACE_GRAPH_PRINT_OVERRUN) - trace_seq_printf(s, " (Overruns: %lu)\n", + trace_seq_printf(s, " (Overruns: %u)\n", trace->overrun); print_graph_irq(iter, trace->func, TRACE_GRAPH_RET, diff --git a/kernel/trace/trace_hwlat.c b/kernel/trace/trace_hwlat.c index d071fc271eef..c0df9b97f147 100644 --- a/kernel/trace/trace_hwlat.c +++ b/kernel/trace/trace_hwlat.c @@ -485,11 +485,11 @@ hwlat_width_write(struct file *filp, const char __user *ubuf, * @ppos: The current position in @file * * This function provides a write implementation for the "window" interface - * to the hardware latency detetector. The window is the total time + * to the hardware latency detector. The window is the total time * in us that will be considered one sample period. Conceptually, windows * occur back-to-back and contain a sample width period during which * actual sampling occurs. Can be used to write a new total window size. It - * is enfoced that any value written must be greater than the sample width + * is enforced that any value written must be greater than the sample width * size, or an error results. */ static ssize_t diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c index 10bbb0f381d5..d06aab4dcbb8 100644 --- a/kernel/trace/trace_irqsoff.c +++ b/kernel/trace/trace_irqsoff.c @@ -138,7 +138,7 @@ static int func_prolog_dec(struct trace_array *tr, */ static void irqsoff_tracer_call(unsigned long ip, unsigned long parent_ip, - struct ftrace_ops *op, struct pt_regs *pt_regs) + struct ftrace_ops *op, struct ftrace_regs *fregs) { struct trace_array *tr = irqsoff_trace; struct trace_array_cpu *data; diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index 97c7a7782db7..9c31f42245e9 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -25,11 +25,12 @@ /* Kprobe early definition from command line */ static char kprobe_boot_events_buf[COMMAND_LINE_SIZE] __initdata; -static bool kprobe_boot_events_enabled __initdata; static int __init set_kprobe_boot_events(char *str) { strlcpy(kprobe_boot_events_buf, str, COMMAND_LINE_SIZE); + disable_tracing_selftest("running kprobe events"); + return 0; } __setup("kprobe_event=", set_kprobe_boot_events); @@ -1888,8 +1889,6 @@ static __init void setup_boot_kprobe_events(void) ret = trace_run_command(cmd, create_or_delete_trace_kprobe); if (ret) pr_warn("Failed to add event(%d): %s\n", ret, cmd); - else - kprobe_boot_events_enabled = true; cmd = p; } @@ -1974,10 +1973,8 @@ static __init int kprobe_trace_self_tests_init(void) if (tracing_is_disabled()) return -ENODEV; - if (kprobe_boot_events_enabled) { - pr_info("Skipping kprobe tests due to kprobe_event on cmdline\n"); + if (tracing_selftest_disabled) return 0; - } target = kprobe_trace_selftest_target; diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c index 000e9dc224c6..92b1575ae0ca 100644 --- a/kernel/trace/trace_output.c +++ b/kernel/trace/trace_output.c @@ -353,8 +353,8 @@ static inline const char *kretprobed(const char *name) } #endif /* CONFIG_KRETPROBES */ -static void -seq_print_sym(struct trace_seq *s, unsigned long address, bool offset) +void +trace_seq_print_sym(struct trace_seq *s, unsigned long address, bool offset) { #ifdef CONFIG_KALLSYMS char str[KSYM_SYMBOL_LEN]; @@ -420,7 +420,7 @@ seq_print_ip_sym(struct trace_seq *s, unsigned long ip, unsigned long sym_flags) goto out; } - seq_print_sym(s, ip, sym_flags & TRACE_ITER_SYM_OFFSET); + trace_seq_print_sym(s, ip, sym_flags & TRACE_ITER_SYM_OFFSET); if (sym_flags & TRACE_ITER_SYM_ADDR) trace_seq_printf(s, " <" IP_FMT ">", ip); diff --git a/kernel/trace/trace_output.h b/kernel/trace/trace_output.h index 2f742b74e7e6..4c954636caf0 100644 --- a/kernel/trace/trace_output.h +++ b/kernel/trace/trace_output.h @@ -16,6 +16,7 @@ extern int seq_print_ip_sym(struct trace_seq *s, unsigned long ip, unsigned long sym_flags); +extern void trace_seq_print_sym(struct trace_seq *s, unsigned long address, bool offset); extern int trace_print_context(struct trace_iterator *iter); extern int trace_print_lat_context(struct trace_iterator *iter); diff --git a/kernel/trace/trace_recursion_record.c b/kernel/trace/trace_recursion_record.c new file mode 100644 index 000000000000..b2edac1fe156 --- /dev/null +++ b/kernel/trace/trace_recursion_record.c @@ -0,0 +1,236 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include <linux/seq_file.h> +#include <linux/kallsyms.h> +#include <linux/module.h> +#include <linux/ftrace.h> +#include <linux/fs.h> + +#include "trace_output.h" + +struct recursed_functions { + unsigned long ip; + unsigned long parent_ip; +}; + +static struct recursed_functions recursed_functions[CONFIG_FTRACE_RECORD_RECURSION_SIZE]; +static atomic_t nr_records; + +/* + * Cache the last found function. Yes, updates to this is racey, but + * so is memory cache ;-) + */ +static unsigned long cached_function; + +void ftrace_record_recursion(unsigned long ip, unsigned long parent_ip) +{ + int index = 0; + int i; + unsigned long old; + + again: + /* First check the last one recorded */ + if (ip == cached_function) + return; + + i = atomic_read(&nr_records); + /* nr_records is -1 when clearing records */ + smp_mb__after_atomic(); + if (i < 0) + return; + + /* + * If there's two writers and this writer comes in second, + * the cmpxchg() below to update the ip will fail. Then this + * writer will try again. It is possible that index will now + * be greater than nr_records. This is because the writer + * that succeeded has not updated the nr_records yet. + * This writer could keep trying again until the other writer + * updates nr_records. But if the other writer takes an + * interrupt, and that interrupt locks up that CPU, we do + * not want this CPU to lock up due to the recursion protection, + * and have a bug report showing this CPU as the cause of + * locking up the computer. To not lose this record, this + * writer will simply use the next position to update the + * recursed_functions, and it will update the nr_records + * accordingly. + */ + if (index < i) + index = i; + if (index >= CONFIG_FTRACE_RECORD_RECURSION_SIZE) + return; + + for (i = index - 1; i >= 0; i--) { + if (recursed_functions[i].ip == ip) { + cached_function = ip; + return; + } + } + + cached_function = ip; + + /* + * We only want to add a function if it hasn't been added before. + * Add to the current location before incrementing the count. + * If it fails to add, then increment the index (save in i) + * and try again. + */ + old = cmpxchg(&recursed_functions[index].ip, 0, ip); + if (old != 0) { + /* Did something else already added this for us? */ + if (old == ip) + return; + /* Try the next location (use i for the next index) */ + index++; + goto again; + } + + recursed_functions[index].parent_ip = parent_ip; + + /* + * It's still possible that we could race with the clearing + * CPU0 CPU1 + * ---- ---- + * ip = func + * nr_records = -1; + * recursed_functions[0] = 0; + * i = -1 + * if (i < 0) + * nr_records = 0; + * (new recursion detected) + * recursed_functions[0] = func + * cmpxchg(recursed_functions[0], + * func, 0) + * + * But the worse that could happen is that we get a zero in + * the recursed_functions array, and it's likely that "func" will + * be recorded again. + */ + i = atomic_read(&nr_records); + smp_mb__after_atomic(); + if (i < 0) + cmpxchg(&recursed_functions[index].ip, ip, 0); + else if (i <= index) + atomic_cmpxchg(&nr_records, i, index + 1); +} +EXPORT_SYMBOL_GPL(ftrace_record_recursion); + +static DEFINE_MUTEX(recursed_function_lock); +static struct trace_seq *tseq; + +static void *recursed_function_seq_start(struct seq_file *m, loff_t *pos) +{ + void *ret = NULL; + int index; + + mutex_lock(&recursed_function_lock); + index = atomic_read(&nr_records); + if (*pos < index) { + ret = &recursed_functions[*pos]; + } + + tseq = kzalloc(sizeof(*tseq), GFP_KERNEL); + if (!tseq) + return ERR_PTR(-ENOMEM); + + trace_seq_init(tseq); + + return ret; +} + +static void *recursed_function_seq_next(struct seq_file *m, void *v, loff_t *pos) +{ + int index; + int p; + + index = atomic_read(&nr_records); + p = ++(*pos); + + return p < index ? &recursed_functions[p] : NULL; +} + +static void recursed_function_seq_stop(struct seq_file *m, void *v) +{ + kfree(tseq); + mutex_unlock(&recursed_function_lock); +} + +static int recursed_function_seq_show(struct seq_file *m, void *v) +{ + struct recursed_functions *record = v; + int ret = 0; + + if (record) { + trace_seq_print_sym(tseq, record->parent_ip, true); + trace_seq_puts(tseq, ":\t"); + trace_seq_print_sym(tseq, record->ip, true); + trace_seq_putc(tseq, '\n'); + ret = trace_print_seq(m, tseq); + } + + return ret; +} + +static const struct seq_operations recursed_function_seq_ops = { + .start = recursed_function_seq_start, + .next = recursed_function_seq_next, + .stop = recursed_function_seq_stop, + .show = recursed_function_seq_show +}; + +static int recursed_function_open(struct inode *inode, struct file *file) +{ + int ret = 0; + + mutex_lock(&recursed_function_lock); + /* If this file was opened for write, then erase contents */ + if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) { + /* disable updating records */ + atomic_set(&nr_records, -1); + smp_mb__after_atomic(); + memset(recursed_functions, 0, sizeof(recursed_functions)); + smp_wmb(); + /* enable them again */ + atomic_set(&nr_records, 0); + } + if (file->f_mode & FMODE_READ) + ret = seq_open(file, &recursed_function_seq_ops); + mutex_unlock(&recursed_function_lock); + + return ret; +} + +static ssize_t recursed_function_write(struct file *file, + const char __user *buffer, + size_t count, loff_t *ppos) +{ + return count; +} + +static int recursed_function_release(struct inode *inode, struct file *file) +{ + if (file->f_mode & FMODE_READ) + seq_release(inode, file); + return 0; +} + +static const struct file_operations recursed_functions_fops = { + .open = recursed_function_open, + .write = recursed_function_write, + .read = seq_read, + .llseek = seq_lseek, + .release = recursed_function_release, +}; + +__init static int create_recursed_functions(void) +{ + struct dentry *dentry; + + dentry = trace_create_file("recursed_functions", 0644, NULL, NULL, + &recursed_functions_fops); + if (!dentry) + pr_warn("WARNING: Failed to create recursed_functions\n"); + return 0; +} + +fs_initcall(create_recursed_functions); diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c index 97b10bb31a1f..c0181066dbe9 100644 --- a/kernel/trace/trace_sched_wakeup.c +++ b/kernel/trace/trace_sched_wakeup.c @@ -212,7 +212,7 @@ static void wakeup_print_header(struct seq_file *s) */ static void wakeup_tracer_call(unsigned long ip, unsigned long parent_ip, - struct ftrace_ops *op, struct pt_regs *pt_regs) + struct ftrace_ops *op, struct ftrace_regs *fregs) { struct trace_array *tr = wakeup_trace; struct trace_array_cpu *data; diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c index 4738ad48a667..73ef12092250 100644 --- a/kernel/trace/trace_selftest.c +++ b/kernel/trace/trace_selftest.c @@ -107,7 +107,7 @@ static int trace_selftest_test_probe1_cnt; static void trace_selftest_test_probe1_func(unsigned long ip, unsigned long pip, struct ftrace_ops *op, - struct pt_regs *pt_regs) + struct ftrace_regs *fregs) { trace_selftest_test_probe1_cnt++; } @@ -116,7 +116,7 @@ static int trace_selftest_test_probe2_cnt; static void trace_selftest_test_probe2_func(unsigned long ip, unsigned long pip, struct ftrace_ops *op, - struct pt_regs *pt_regs) + struct ftrace_regs *fregs) { trace_selftest_test_probe2_cnt++; } @@ -125,7 +125,7 @@ static int trace_selftest_test_probe3_cnt; static void trace_selftest_test_probe3_func(unsigned long ip, unsigned long pip, struct ftrace_ops *op, - struct pt_regs *pt_regs) + struct ftrace_regs *fregs) { trace_selftest_test_probe3_cnt++; } @@ -134,7 +134,7 @@ static int trace_selftest_test_global_cnt; static void trace_selftest_test_global_func(unsigned long ip, unsigned long pip, struct ftrace_ops *op, - struct pt_regs *pt_regs) + struct ftrace_regs *fregs) { trace_selftest_test_global_cnt++; } @@ -143,24 +143,21 @@ static int trace_selftest_test_dyn_cnt; static void trace_selftest_test_dyn_func(unsigned long ip, unsigned long pip, struct ftrace_ops *op, - struct pt_regs *pt_regs) + struct ftrace_regs *fregs) { trace_selftest_test_dyn_cnt++; } static struct ftrace_ops test_probe1 = { .func = trace_selftest_test_probe1_func, - .flags = FTRACE_OPS_FL_RECURSION_SAFE, }; static struct ftrace_ops test_probe2 = { .func = trace_selftest_test_probe2_func, - .flags = FTRACE_OPS_FL_RECURSION_SAFE, }; static struct ftrace_ops test_probe3 = { .func = trace_selftest_test_probe3_func, - .flags = FTRACE_OPS_FL_RECURSION_SAFE, }; static void print_counts(void) @@ -417,7 +414,7 @@ static int trace_selftest_recursion_cnt; static void trace_selftest_test_recursion_func(unsigned long ip, unsigned long pip, struct ftrace_ops *op, - struct pt_regs *pt_regs) + struct ftrace_regs *fregs) { /* * This function is registered without the recursion safe flag. @@ -432,7 +429,7 @@ static void trace_selftest_test_recursion_func(unsigned long ip, static void trace_selftest_test_recursion_safe_func(unsigned long ip, unsigned long pip, struct ftrace_ops *op, - struct pt_regs *pt_regs) + struct ftrace_regs *fregs) { /* * We said we would provide our own recursion. By calling @@ -448,11 +445,11 @@ static void trace_selftest_test_recursion_safe_func(unsigned long ip, static struct ftrace_ops test_rec_probe = { .func = trace_selftest_test_recursion_func, + .flags = FTRACE_OPS_FL_RECURSION, }; static struct ftrace_ops test_recsafe_probe = { .func = trace_selftest_test_recursion_safe_func, - .flags = FTRACE_OPS_FL_RECURSION_SAFE, }; static int @@ -551,9 +548,11 @@ static enum { static void trace_selftest_test_regs_func(unsigned long ip, unsigned long pip, struct ftrace_ops *op, - struct pt_regs *pt_regs) + struct ftrace_regs *fregs) { - if (pt_regs) + struct pt_regs *regs = ftrace_get_regs(fregs); + + if (regs) trace_selftest_regs_stat = TRACE_SELFTEST_REGS_FOUND; else trace_selftest_regs_stat = TRACE_SELFTEST_REGS_NOT_FOUND; @@ -561,7 +560,7 @@ static void trace_selftest_test_regs_func(unsigned long ip, static struct ftrace_ops test_regs_probe = { .func = trace_selftest_test_regs_func, - .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_SAVE_REGS, + .flags = FTRACE_OPS_FL_SAVE_REGS, }; static int @@ -787,7 +786,7 @@ trace_selftest_startup_function_graph(struct tracer *trace, /* Have we just recovered from a hang? */ if (graph_hang_thresh > GRAPH_MAX_FUNC_TEST) { - tracing_selftest_disabled = true; + disable_tracing_selftest("recovering from a hang"); ret = -1; goto out; } diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c index c408423e5d65..63c285042051 100644 --- a/kernel/trace/trace_stack.c +++ b/kernel/trace/trace_stack.c @@ -290,7 +290,7 @@ static void check_stack(unsigned long ip, unsigned long *stack) static void stack_trace_call(unsigned long ip, unsigned long parent_ip, - struct ftrace_ops *op, struct pt_regs *pt_regs) + struct ftrace_ops *op, struct ftrace_regs *fregs) { unsigned long stack; @@ -318,7 +318,6 @@ stack_trace_call(unsigned long ip, unsigned long parent_ip, static struct ftrace_ops trace_ops __read_mostly = { .func = stack_trace_call, - .flags = FTRACE_OPS_FL_RECURSION_SAFE, }; static ssize_t diff --git a/kernel/trace/tracing_map.c b/kernel/trace/tracing_map.c index 4b50fc0cb12c..d6bddb157ef2 100644 --- a/kernel/trace/tracing_map.c +++ b/kernel/trace/tracing_map.c @@ -609,7 +609,7 @@ __tracing_map_insert(struct tracing_map *map, void *key, bool lookup_only) * signal that state. There are two user-visible tracing_map * variables, 'hits' and 'drops', which are updated by this function. * Every time an element is either successfully inserted or retrieved, - * the 'hits' value is incrememented. Every time an element insertion + * the 'hits' value is incremented. Every time an element insertion * fails, the 'drops' value is incremented. * * This is a lock-free tracing map insertion function implementing a @@ -642,9 +642,9 @@ struct tracing_map_elt *tracing_map_insert(struct tracing_map *map, void *key) * tracing_map_elt. This is a lock-free lookup; see * tracing_map_insert() for details on tracing_map and how it works. * Every time an element is retrieved, the 'hits' value is - * incrememented. There is one user-visible tracing_map variable, + * incremented. There is one user-visible tracing_map variable, * 'hits', which is updated by this function. Every time an element - * is successfully retrieved, the 'hits' value is incrememented. The + * is successfully retrieved, the 'hits' value is incremented. The * 'drops' value is never updated by this function. * * Return: the tracing_map_elt pointer val associated with the key. diff --git a/kernel/trace/tracing_map.h b/kernel/trace/tracing_map.h index a6de61fc22de..2c765ee2a4d4 100644 --- a/kernel/trace/tracing_map.h +++ b/kernel/trace/tracing_map.h @@ -50,7 +50,7 @@ typedef int (*tracing_map_cmp_fn_t) (void *val_a, void *val_b); * an instance of tracing_map_elt, where 'elt' in the latter part of * that variable name is short for 'element'. The purpose of a * tracing_map_elt is to hold values specific to the particular - * 32-bit hashed key it's assocated with. Things such as the unique + * 32-bit hashed key it's associated with. Things such as the unique * set of aggregated sums associated with the 32-bit hashed key, along * with a copy of the full key associated with the entry, and which * was used to produce the 32-bit hashed key. |