| Commit message (Collapse) | Author | Age | Files | Lines |
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The trampoline allocated by function tracer was overwriten by function_graph
tracer, and caused a memory leak. The save_global_trampoline should have
saved the previous trampoline in register_ftrace_graph() and restored it in
unregister_ftrace_graph(). But as it is implemented, save_global_trampoline was
only used in unregister_ftrace_graph as default value 0, and it overwrote the
previous trampoline's value. Causing the previous allocated trampoline to be
lost.
kmmeleak backtrace:
kmemleak_vmalloc+0x77/0xc0
__vmalloc_node_range+0x1b5/0x2c0
module_alloc+0x7c/0xd0
arch_ftrace_update_trampoline+0xb5/0x290
ftrace_startup+0x78/0x210
register_ftrace_function+0x8b/0xd0
function_trace_init+0x4f/0x80
tracing_set_tracer+0xe6/0x170
tracing_set_trace_write+0x90/0xd0
__vfs_write+0x37/0x170
vfs_write+0xb2/0x1b0
SyS_write+0x55/0xc0
do_syscall_64+0x67/0x180
return_from_SYSCALL_64+0x0/0x6a
[
Looking further into this, I found that this was left over from when the
function and function graph tracers shared the same ftrace_ops. But in
commit 5f151b2401 ("ftrace: Fix function_profiler and function tracer
together"), the two were separated, and the save_global_trampoline no
longer was necessary (and it may have been broken back then too).
-- Steven Rostedt
]
Link: http://lkml.kernel.org/r/20170912021454.5976-1-shuwang@redhat.com
Cc: stable@vger.kernel.org
Fixes: 5f151b2401 ("ftrace: Fix function_profiler and function tracer together")
Signed-off-by: Shu Wang <shuwang@redhat.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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If function tracing is disabled by the user via the function-trace option or
the proc sysctl file, and a ftrace_ops that was allocated on the heap is
unregistered, then the shutdown code exits out without doing the proper
clean up. This was found via kmemleak and running the ftrace selftests, as
one of the tests unregisters with function tracing disabled.
# cat kmemleak
unreferenced object 0xffffffffa0020000 (size 4096):
comm "swapper/0", pid 1, jiffies 4294668889 (age 569.209s)
hex dump (first 32 bytes):
55 ff 74 24 10 55 48 89 e5 ff 74 24 18 55 48 89 U.t$.UH...t$.UH.
e5 48 81 ec a8 00 00 00 48 89 44 24 50 48 89 4c .H......H.D$PH.L
backtrace:
[<ffffffff81d64665>] kmemleak_vmalloc+0x85/0xf0
[<ffffffff81355631>] __vmalloc_node_range+0x281/0x3e0
[<ffffffff8109697f>] module_alloc+0x4f/0x90
[<ffffffff81091170>] arch_ftrace_update_trampoline+0x160/0x420
[<ffffffff81249947>] ftrace_startup+0xe7/0x300
[<ffffffff81249bd2>] register_ftrace_function+0x72/0x90
[<ffffffff81263786>] trace_selftest_ops+0x204/0x397
[<ffffffff82bb8971>] trace_selftest_startup_function+0x394/0x624
[<ffffffff81263a75>] run_tracer_selftest+0x15c/0x1d7
[<ffffffff82bb83f1>] init_trace_selftests+0x75/0x192
[<ffffffff81002230>] do_one_initcall+0x90/0x1e2
[<ffffffff82b7d620>] kernel_init_freeable+0x350/0x3fe
[<ffffffff81d61ec3>] kernel_init+0x13/0x122
[<ffffffff81d72c6a>] ret_from_fork+0x2a/0x40
[<ffffffffffffffff>] 0xffffffffffffffff
Cc: stable@vger.kernel.org
Fixes: 12cce594fa ("ftrace/x86: Allow !CONFIG_PREEMPT dynamic ops to use allocated trampolines")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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When a ftrace filter has a module function, and that module is removed, the
filter still has its address as being enabled. This can cause interesting
side effects. Nothing dangerous, but unwanted functions can be traced
because of it.
# cd /sys/kernel/tracing
# echo ':mod:snd_seq' > set_ftrace_filter
# cat set_ftrace_filter
snd_use_lock_sync_helper [snd_seq]
check_event_type_and_length [snd_seq]
snd_seq_ioctl_pversion [snd_seq]
snd_seq_ioctl_client_id [snd_seq]
snd_seq_ioctl_get_queue_tempo [snd_seq]
update_timestamp_of_queue [snd_seq]
snd_seq_ioctl_get_queue_status [snd_seq]
snd_seq_set_queue_tempo [snd_seq]
snd_seq_ioctl_set_queue_tempo [snd_seq]
snd_seq_ioctl_get_queue_timer [snd_seq]
seq_free_client1 [snd_seq]
[..]
# rmmod snd_seq
# cat set_ftrace_filter
# modprobe kvm
# cat set_ftrace_filter
kvm_set_cr4 [kvm]
kvm_emulate_hypercall [kvm]
kvm_set_dr [kvm]
This is because removing the snd_seq module after it was being filtered,
left the address of the snd_seq functions in the hash. When the kvm module
was loaded, some of its functions were loaded at the same address as the
snd_seq module. This would enable them to be filtered and traced.
Now we don't want to clear the hash completely. That would cause removing a
module where only its functions are filtered, to cause the tracing to enable
all functions, as an empty filter means to trace all functions. Instead,
just set the hash ip address to zero. Then it will never match any function.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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There's a small race when function graph shutsdown and the calling of the
registered function graph entry callback. The callback must not reference
the task's ret_stack without first checking that it is not NULL. Note, when
a ret_stack is allocated for a task, it stays allocated until the task exits.
The problem here, is that function_graph is shutdown, and a new task was
created, which doesn't have its ret_stack allocated. But since some of the
functions are still being traced, the callbacks can still be called.
The normal function_graph code handles this, but starting with commit
8861dd303c ("ftrace: Access ret_stack->subtime only in the function
profiler") the profiler code references the ret_stack on function entry, but
doesn't check if it is NULL first.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=196611
Cc: stable@vger.kernel.org
Fixes: 8861dd303c ("ftrace: Access ret_stack->subtime only in the function profiler")
Reported-by: lilydjwg@gmail.com
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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The variables which are processed by RCU functions should be annotated
as RCU, otherwise sparse will report the errors like below:
"error: incompatible types in comparison expression (different
address spaces)"
Link: http://lkml.kernel.org/r/1496823171-7758-1-git-send-email-zhang.chunyan@linaro.org
Signed-off-by: Chunyan Zhang <zhang.chunyan@linaro.org>
[ Updated to not be 100% 80 column strict ]
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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My static checker complains that if "func" is NULL then "clear_filter"
is uninitialized. This seems like it could be true, although it's
possible something subtle is happening that I haven't seen.
kernel/trace/ftrace.c:3844 match_records()
error: uninitialized symbol 'clear_filter'.
Link: http://lkml.kernel.org/r/20170712073556.h6tkpjcdzjaozozs@mwanda
Cc: stable@vger.kernel.org
Fixes: f0a3b154bd7 ("ftrace: Clarify code for mod command")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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"func" can't be NULL and it doesn't make sense to check because we've
already derefenced it.
Link: http://lkml.kernel.org/r/20170712073340.4enzeojeoupuds5a@mwanda
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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When modules are disabled, we get a harmless build warning:
kernel/trace/ftrace.c:4051:13: error: 'process_cached_mods' defined but not used [-Werror=unused-function]
This adds the same #ifdef around the new code that exists around
its caller.
Link: http://lkml.kernel.org/r/20170710084413.1820568-1-arnd@arndb.de
Fixes: d7fbf8df7ca0 ("ftrace: Implement cached modules tracing on module load")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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As writing into stack_trace_filter, the iter-tr is not set and is NULL.
Check if it is NULL before dereferencing it in ftrace_regex_release().
Fixes: 8c08f0d5c6fb ("ftrace: Have cached module filters be an active filter")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Need to get the changes from 0f17976568b3 ("ftrace: Fix regression with
module command in stack_trace_filter") as it is required to fix some other
changes with stack_trace_filter and the new development code.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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When doing the following command:
# echo ":mod:kvm_intel" > /sys/kernel/tracing/stack_trace_filter
it triggered a crash.
This happened with the clean up of probes. It required all callers to the
regex function (doing ftrace filtering) to have ops->private be a pointer to
a trace_array. But for the stack tracer, that is not the case.
Allow for the ops->private to be NULL, and change the function command
callbacks to handle the trace_array pointer being NULL as well.
Fixes: d2afd57a4b96 ("tracing/ftrace: Allow instances to have their own function probes")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Init boot up functions may be traced, but they are also freed when the
kernel finishes booting. These are removed from the ftrace tables, and the
debug variable for dyn_ftrace_total_info needs to reflect that as well.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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If the new_hash fails to allocate, then unlock the hash mutex on error.
Reported-by: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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The dyn_ftrace_total_info file is used to show how many functions have been
converted into nops and can be used by ftrace. The problem is that it does
not get decremented when functions are removed (init boot code being freed,
and modules being freed). That means the number is very inaccurate everytime
functions are removed from the ftrace tables. Decrement it when functions
are removed.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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When a module filter is added to set_ftrace_filter, if the module is not
loaded, it is cached. This should be considered an active filter, and
function tracing should be filtered by this. That is, if a cached module
filter is the only filter set, then no function tracing should be happening,
as all the functions available will be filtered out.
This makes sense, as the reason to add a cached module filter, is to trace
the module when you load it. There shouldn't be any other tracing happening
until then.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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If a module is cached in the set_ftrace_filter, and that module is loaded,
then enable tracing on that module as if the cached module text was written
into set_ftrace_filter just as the module is loaded.
# echo ":mod:kvm_intel" >
# cat /sys/kernel/tracing/set_ftrace_filter
#### all functions enabled ####
:mod:kvm_intel
# modprobe kvm_intel
# cat /sys/kernel/tracing/set_ftrace_filter
vmx_get_rflags [kvm_intel]
vmx_get_pkru [kvm_intel]
vmx_get_interrupt_shadow [kvm_intel]
vmx_rdtscp_supported [kvm_intel]
vmx_invpcid_supported [kvm_intel]
[..]
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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When writing in a module filter into set_ftrace_filter for a module that is
not yet loaded, it it cached, and will be executed when the module is loaded
(although that is not implemented yet at this commit). Display the list of
cached modules to be traced.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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This is the start of the infrastructure work to allow for tracing module
functions before it is loaded.
Currently the following command:
# echo :mod:some-mod > set_ftrace_filter
will enable tracing of all functions within the module "some-mod" if it is
loaded. What we want, is if the module is not loaded, that line will be
saved. When the module is loaded, then the "some-mod" will have that line
executed on it, so that the functions within it starts being traced.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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ftrace_hash is being kfree'ed in ftrace_graph_release(), however the
->buckets field is not. This results in a memory leak that is easily
captured by kmemleak:
unreferenced object 0xffff880038afe000 (size 8192):
comm "trace-cmd", pid 238, jiffies 4294916898 (age 9.736s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<ffffffff815f561e>] kmemleak_alloc+0x4e/0xb0
[<ffffffff8113964d>] __kmalloc+0x12d/0x1a0
[<ffffffff810bf6d1>] alloc_ftrace_hash+0x51/0x80
[<ffffffff810c0523>] __ftrace_graph_open.isra.39.constprop.46+0xa3/0x100
[<ffffffff810c05e8>] ftrace_graph_open+0x68/0xa0
[<ffffffff8114003d>] do_dentry_open.isra.1+0x1bd/0x2d0
[<ffffffff81140df7>] vfs_open+0x47/0x60
[<ffffffff81150f95>] path_openat+0x2a5/0x1020
[<ffffffff81152d6a>] do_filp_open+0x8a/0xf0
[<ffffffff811411df>] do_sys_open+0x12f/0x200
[<ffffffff811412ce>] SyS_open+0x1e/0x20
[<ffffffff815fa6e0>] entry_SYSCALL_64_fastpath+0x13/0x94
[<ffffffffffffffff>] 0xffffffffffffffff
Link: http://lkml.kernel.org/r/20170525152038.7661-1-lhenriques@suse.com
Cc: stable@vger.kernel.org
Fixes: b9b0c831bed2 ("ftrace: Convert graph filter to use hash tables")
Signed-off-by: Luis Henriques <lhenriques@suse.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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If instance directories are deleted while there are registered function
triggers:
# cd /sys/kernel/debug/tracing/instances
# mkdir test
# echo "schedule:enable_event:sched:sched_switch" > test/set_ftrace_filter
# rmdir test
Unable to handle kernel paging request for data at address 0x00000008
Unable to handle kernel paging request for data at address 0x00000008
Faulting instruction address: 0xc0000000021edde8
Oops: Kernel access of bad area, sig: 11 [#1]
SMP NR_CPUS=2048
NUMA
pSeries
Modules linked in: iptable_mangle ipt_MASQUERADE nf_nat_masquerade_ipv4 iptable_nat nf_nat_ipv4 nf_nat nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack nf_conntrack ipt_REJECT nf_reject_ipv4 xt_tcpudp tun bridge stp llc kvm iptable_filter fuse binfmt_misc pseries_rng rng_core vmx_crypto ib_iser rdma_cm iw_cm ib_cm ib_core libiscsi scsi_transport_iscsi ip_tables x_tables autofs4 btrfs raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c multipath virtio_net virtio_blk virtio_pci crc32c_vpmsum virtio_ring virtio
CPU: 8 PID: 8694 Comm: rmdir Not tainted 4.11.0-nnr+ #113
task: c0000000bab52800 task.stack: c0000000baba0000
NIP: c0000000021edde8 LR: c0000000021f0590 CTR: c000000002119620
REGS: c0000000baba3870 TRAP: 0300 Not tainted (4.11.0-nnr+)
MSR: 8000000000009033 <SF,EE,ME,IR,DR,RI,LE>
CR: 22002422 XER: 20000000
CFAR: 00007fffabb725a8 DAR: 0000000000000008 DSISR: 40000000 SOFTE: 0
GPR00: c00000000220f750 c0000000baba3af0 c000000003157e00 0000000000000000
GPR04: 0000000000000040 00000000000000eb 0000000000000040 0000000000000000
GPR08: 0000000000000000 0000000000000113 0000000000000000 c00000000305db98
GPR12: c000000002119620 c00000000fd42c00 0000000000000000 0000000000000000
GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
GPR20: 0000000000000000 0000000000000000 c0000000bab52e90 0000000000000000
GPR24: 0000000000000000 00000000000000eb 0000000000000040 c0000000baba3bb0
GPR28: c00000009cb06eb0 c0000000bab52800 c00000009cb06eb0 c0000000baba3bb0
NIP [c0000000021edde8] ring_buffer_lock_reserve+0x8/0x4e0
LR [c0000000021f0590] trace_event_buffer_lock_reserve+0xe0/0x1a0
Call Trace:
[c0000000baba3af0] [c0000000021f96c8] trace_event_buffer_commit+0x1b8/0x280 (unreliable)
[c0000000baba3b60] [c00000000220f750] trace_event_buffer_reserve+0x80/0xd0
[c0000000baba3b90] [c0000000021196b8] trace_event_raw_event_sched_switch+0x98/0x180
[c0000000baba3c10] [c0000000029d9980] __schedule+0x6e0/0xab0
[c0000000baba3ce0] [c000000002122230] do_task_dead+0x70/0xc0
[c0000000baba3d10] [c0000000020ea9c8] do_exit+0x828/0xd00
[c0000000baba3dd0] [c0000000020eaf70] do_group_exit+0x60/0x100
[c0000000baba3e10] [c0000000020eb034] SyS_exit_group+0x24/0x30
[c0000000baba3e30] [c00000000200bcec] system_call+0x38/0x54
Instruction dump:
60000000 60420000 7d244b78 7f63db78 4bffaa09 393efff8 793e0020 39200000
4bfffecc 60420000 3c4c00f7 3842a020 <81230008> 2f890000 409e02f0 a14d0008
---[ end trace b917b8985d0e650b ]---
Unable to handle kernel paging request for data at address 0x00000008
Faulting instruction address: 0xc0000000021edde8
Unable to handle kernel paging request for data at address 0x00000008
Faulting instruction address: 0xc0000000021edde8
Faulting instruction address: 0xc0000000021edde8
To address this, let's clear all registered function probes before
deleting the ftrace instance.
Link: http://lkml.kernel.org/r/c5f1ca624043690bd94642bb6bffd3f2fc504035.1494956770.git.naveen.n.rao@linux.vnet.ibm.com
Reported-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Handle a NULL glob properly and simplify the check.
Link: http://lkml.kernel.org/r/5df74d4ffb4721db6d5a22fa08ca031d62ead493.1494956770.git.naveen.n.rao@linux.vnet.ibm.com
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Dan Carpenter sent a patch to remove a check in ftrace_match_record()
because the logic of the code made the check redundant. I looked deeper into
the code, and made the following logic table, with the three variables and
the result of the original code.
modname mod_matches exclude_mod result
------- ----------- ----------- ------
0 0 0 return 0
0 0 1 func_match
0 1 * < cannot exist >
1 0 0 return 0
1 0 1 func_match
1 1 0 func_match
1 1 1 return 0
Notice that when mod_matches == exclude mod, the result is always to
return 0, and when mod_matches != exclude_mod, then the result is to test
the function. This means we only need test if mod_matches is equal to
exclude_mod.
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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We know that "mod_matches" is true here so there is no need to check
again.
Link: http://lkml.kernel.org/r/20170331152130.GA4947@mwanda
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt:
"New features for this release:
- Pretty much a full rewrite of the processing of function plugins.
i.e. echo do_IRQ:stacktrace > set_ftrace_filter
- The rewrite was needed to add plugins to be unique to tracing
instances. i.e. mkdir instance/foo; cd instances/foo; echo
do_IRQ:stacktrace > set_ftrace_filter The old way was written very
hacky. This removes a lot of those hacks.
- New "function-fork" tracing option. When set, pids in the
set_ftrace_pid will have their children added when the processes
with their pids listed in the set_ftrace_pid file forks.
- Exposure of "maxactive" for kretprobe in kprobe_events
- Allow for builtin init functions to be traced by the function
tracer (via the kernel command line). Module init function tracing
will come in the next release.
- Added more selftests, and have selftests also test in an instance"
* tag 'trace-v4.12' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (60 commits)
ring-buffer: Return reader page back into existing ring buffer
selftests: ftrace: Allow some event trigger tests to run in an instance
selftests: ftrace: Have some basic tests run in a tracing instance too
selftests: ftrace: Have event tests also run in an tracing instance
selftests: ftrace: Make func_event_triggers and func_traceonoff_triggers tests do instances
selftests: ftrace: Allow some tests to be run in a tracing instance
tracing/ftrace: Allow for instances to trigger their own stacktrace probes
tracing/ftrace: Allow for the traceonoff probe be unique to instances
tracing/ftrace: Enable snapshot function trigger to work with instances
tracing/ftrace: Allow instances to have their own function probes
tracing/ftrace: Add a better way to pass data via the probe functions
ftrace: Dynamically create the probe ftrace_ops for the trace_array
tracing: Pass the trace_array into ftrace_probe_ops functions
tracing: Have the trace_array hold the list of registered func probes
ftrace: If the hash for a probe fails to update then free what was initialized
ftrace: Have the function probes call their own function
ftrace: Have each function probe use its own ftrace_ops
ftrace: Have unregister_ftrace_function_probe_func() return a value
ftrace: Add helper function ftrace_hash_move_and_update_ops()
ftrace: Remove data field from ftrace_func_probe structure
...
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Pass around the local trace_array that is the descriptor for tracing
instances, when enabling and disabling probes. This by default sets the
enable/disable of event probe triggers to work with instances.
The other probes will need some more work to get them working with
instances.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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With the redesign of the registration and execution of the function probes
(triggers), data can now be passed from the setup of the probe to the probe
callers that are specific to the trace_array it is on. Although, all probes
still only affect the toplevel trace array, this change will allow for
instances to have their own probes separated from other instances and the
top array.
That is, something like the stacktrace probe can be set to trace only in an
instance and not the toplevel trace array. This isn't implement yet, but
this change sets the ground work for the change.
When a probe callback is triggered (someone writes the probe format into
set_ftrace_filter), it calls register_ftrace_function_probe() passing in
init_data that will be used to initialize the probe. Then for every matching
function, register_ftrace_function_probe() will call the probe_ops->init()
function with the init data that was passed to it, as well as an address to
a place holder that is associated with the probe and the instance. The first
occurrence will have a NULL in the pointer. The init() function will then
initialize it. If other probes are added, or more functions are part of the
probe, the place holder will be passed to the init() function with the place
holder data that it was initialized to the last time.
Then this place_holder is passed to each of the other probe_ops functions,
where it can be used in the function callback. When the probe_ops free()
function is called, it can be called either with the rip of the function
that is being removed from the probe, or zero, indicating that there are no
more functions attached to the probe, and the place holder is about to be
freed. This gives the probe_ops a way to free the data it assigned to the
place holder if it was allocade during the first init call.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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In order to eventually have each trace_array instance have its own unique
set of function probes (triggers), the trace array needs to hold the ops and
the filters for the probes.
This is the first step to accomplish this. Instead of having the private
data of the probe ops point to the trace_array, create a separate list that
the trace_array holds. There's only one private_data for a probe, we need
one per trace_array. The probe ftrace_ops will be dynamically created for
each instance, instead of being static.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Pass the trace_array associated to a ftrace_probe_ops into the probe_ops
func(), init() and free() functions. The trace_array is the descriptor that
describes a tracing instance. This will help create the infrastructure that
will allow having function probes unique to tracing instances.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Add a link list to the trace_array to hold func probes that are registered.
Currently, all function probes are the same for all instances as it was
before, that is, only the top level trace_array holds the function probes.
But this lays the ground work to have function probes be attached to
individual instances, and having the event trigger only affect events in the
given instance. But that work is still to be done.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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If the ftrace_hash_move_and_update_ops() fails, and an ops->free() function
exists, then it needs to be called on all the ops that were added by this
registration.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Now that the function probes have their own ftrace_ops, there's no reason to
continue using the ftrace_func_hash to find which probe to call in the
function callback. The ops that is passed in to the function callback is
part of the probe_ops to call.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Have the function probes have their own ftrace_ops, and remove the
trace_probe_ops. This simplifies some of the ftrace infrastructure code.
Individual entries for each function is still allocated for the use of the
output for set_ftrace_filter, but they will be removed soon too.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Currently unregister_ftrace_function_probe_func() is a void function. It
does not give any feedback if an error occurred or no item was found to
remove and nothing was done.
Change it to return status and success if it removed something. Also update
the callers to return that feedback to the user.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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The processes of updating a ops filter_hash is a bit complex, and requires
setting up an old hash to perform the update. This is done exactly the same
in two locations for the same reasons. Create a helper function that does it
in one place.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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No users of the function probes uses the data field anymore. Remove it, and
change the init function to take a void *data parameter instead of a
void **data, because the init will just get the data that the registering
function was received, and there's no state after it is called.
The other functions for ftrace_probe_ops still take the data parameter, but
it will currently only be passed NULL. It will stay as a parameter for
future data to be passed to these functions.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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None of the probe users uses the data field anymore of the entry. They all
have their own print() function. Remove showing the data field in the
generic function as the data field will be going away.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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There are no users of unregister_ftrace_function_probe_all(). The only probe
function that is used is unregister_ftrace_function_probe_func(). Rename the
internal static function __unregister_ftrace_function_probe() to
unregister_ftrace_function_probe_func() and make it global.
Also remove the PROBE_TEST_FUNC as it would be always set.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Nothing calls unregister_ftrace_function_probe(). Remove it as well as the
flag PROBE_TEST_DATA, as this function was the only one to set it.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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In order to move the ops to the function probes directly, they need a way to
map function ips to their own data without depending on the infrastructure
of the function probes, as the data field will be going away.
New helper functions are added that are based on the ftrace_hash code.
ftrace_func_mapper functions are there to let the probes map ips to their
data. These can be allocated by the probe ops, and referenced in the
function callbacks.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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In preparation to cleaning up the probe function registration code, the
"data" parameter will eventually be removed from the probe->func() call.
Instead it will receive its own "ops" function, in which it can set up its
own data that it needs to map.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Nothing uses "flags" in the ftrace_func_probe descriptor. Remove it.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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The function-fork option is same as event-fork that it tracks task
fork/exit and set the pid filter properly. This can be useful if user
wants to trace selected tasks including their children only.
Link: http://lkml.kernel.org/r/20170417024430.21194-3-namhyung@kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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t_hash_start() does not increment *pos, where as t_next() must. But when
t_next() does increment *pos, it must still pass in the original *pos to
t_hash_start() otherwise it will skip the first instance:
# cd /sys/kernel/debug/tracing
# echo schedule:traceoff > set_ftrace_filter
# echo do_IRQ:traceoff > set_ftrace_filter
# echo call_rcu > set_ftrace_filter
# cat set_ftrace_filter
call_rcu
schedule:traceoff:unlimited
do_IRQ:traceoff:unlimited
The above called t_hash_start() from t_start() as there was only one
function (call_rcu), but if we add another function:
# echo xfrm_policy_destroy_rcu >> set_ftrace_filter
# cat set_ftrace_filter
call_rcu
xfrm_policy_destroy_rcu
do_IRQ:traceoff:unlimited
The "schedule:traceoff" disappears.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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When two function probes are added to set_ftrace_filter, and then one of
them is removed, the update to the function locations is not performed, and
the record keeping of the function states are corrupted, and causes an
ftrace_bug() to occur.
This is easily reproducable by adding two probes, removing one, and then
adding it back again.
# cd /sys/kernel/debug/tracing
# echo schedule:traceoff > set_ftrace_filter
# echo do_IRQ:traceoff > set_ftrace_filter
# echo \!do_IRQ:traceoff > /debug/tracing/set_ftrace_filter
# echo do_IRQ:traceoff > set_ftrace_filter
Causes:
------------[ cut here ]------------
WARNING: CPU: 2 PID: 1098 at kernel/trace/ftrace.c:2369 ftrace_get_addr_curr+0x143/0x220
Modules linked in: [...]
CPU: 2 PID: 1098 Comm: bash Not tainted 4.10.0-test+ #405
Hardware name: Hewlett-Packard HP Compaq Pro 6300 SFF/339A, BIOS K01 v02.05 05/07/2012
Call Trace:
dump_stack+0x68/0x9f
__warn+0x111/0x130
? trace_irq_work_interrupt+0xa0/0xa0
warn_slowpath_null+0x1d/0x20
ftrace_get_addr_curr+0x143/0x220
? __fentry__+0x10/0x10
ftrace_replace_code+0xe3/0x4f0
? ftrace_int3_handler+0x90/0x90
? printk+0x99/0xb5
? 0xffffffff81000000
ftrace_modify_all_code+0x97/0x110
arch_ftrace_update_code+0x10/0x20
ftrace_run_update_code+0x1c/0x60
ftrace_run_modify_code.isra.48.constprop.62+0x8e/0xd0
register_ftrace_function_probe+0x4b6/0x590
? ftrace_startup+0x310/0x310
? debug_lockdep_rcu_enabled.part.4+0x1a/0x30
? update_stack_state+0x88/0x110
? ftrace_regex_write.isra.43.part.44+0x1d3/0x320
? preempt_count_sub+0x18/0xd0
? mutex_lock_nested+0x104/0x800
? ftrace_regex_write.isra.43.part.44+0x1d3/0x320
? __unwind_start+0x1c0/0x1c0
? _mutex_lock_nest_lock+0x800/0x800
ftrace_trace_probe_callback.isra.3+0xc0/0x130
? func_set_flag+0xe0/0xe0
? __lock_acquire+0x642/0x1790
? __might_fault+0x1e/0x20
? trace_get_user+0x398/0x470
? strcmp+0x35/0x60
ftrace_trace_onoff_callback+0x48/0x70
ftrace_regex_write.isra.43.part.44+0x251/0x320
? match_records+0x420/0x420
ftrace_filter_write+0x2b/0x30
__vfs_write+0xd7/0x330
? do_loop_readv_writev+0x120/0x120
? locks_remove_posix+0x90/0x2f0
? do_lock_file_wait+0x160/0x160
? __lock_is_held+0x93/0x100
? rcu_read_lock_sched_held+0x5c/0xb0
? preempt_count_sub+0x18/0xd0
? __sb_start_write+0x10a/0x230
? vfs_write+0x222/0x240
vfs_write+0xef/0x240
SyS_write+0xab/0x130
? SyS_read+0x130/0x130
? trace_hardirqs_on_caller+0x182/0x280
? trace_hardirqs_on_thunk+0x1a/0x1c
entry_SYSCALL_64_fastpath+0x18/0xad
RIP: 0033:0x7fe61c157c30
RSP: 002b:00007ffe87890258 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: ffffffff8114a410 RCX: 00007fe61c157c30
RDX: 0000000000000010 RSI: 000055814798f5e0 RDI: 0000000000000001
RBP: ffff8800c9027f98 R08: 00007fe61c422740 R09: 00007fe61ca53700
R10: 0000000000000073 R11: 0000000000000246 R12: 0000558147a36400
R13: 00007ffe8788f160 R14: 0000000000000024 R15: 00007ffe8788f15c
? trace_hardirqs_off_caller+0xc0/0x110
---[ end trace 99fa09b3d9869c2c ]---
Bad trampoline accounting at: ffffffff81cc3b00 (do_IRQ+0x0/0x150)
Cc: stable@vger.kernel.org
Fixes: 59df055f1991 ("ftrace: trace different functions with a different tracer")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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The function tracer needs to be more careful than other subsystems when it
comes to freeing data. Especially if that data is actually executable code.
When a single function is traced, a trampoline can be dynamically allocated
which is called to jump to the function trace callback. When the callback is
no longer needed, the dynamic allocated trampoline needs to be freed. This
is where the issues arise. The dynamically allocated trampoline must not be
used again. As function tracing can trace all subsystems, including
subsystems that are used to serialize aspects of freeing (namely RCU), it
must take extra care when doing the freeing.
Before synchronize_rcu_tasks() was around, there was no way for the function
tracer to know that nothing was using the dynamically allocated trampoline
when CONFIG_PREEMPT was enabled. That's because a task could be indefinitely
preempted while sitting on the trampoline. Now with synchronize_rcu_tasks(),
it will wait till all tasks have either voluntarily scheduled (not on the
trampoline) or goes into userspace (not on the trampoline). Then it is safe
to free the trampoline even with CONFIG_PREEMPT set.
Acked-by: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Relying on free_reserved_area() to call ftrace to free init memory proved to
not be sufficient. The issue is that on x86, when debug_pagealloc is
enabled, the init memory is not freed, but simply set as not present. Since
ftrace was uninformed of this, starting function tracing still tries to
update pages that are not present according to the page tables, causing
ftrace to bug, as well as killing the kernel itself.
Instead of relying on free_reserved_area(), have init/main.c call ftrace
directly just before it frees the init memory. Then it needs to use
__init_begin and __init_end to know where the init memory location is.
Looking at all archs (and testing what I can), it appears that this should
work for each of them.
Reported-by: kernel test robot <xiaolong.ye@intel.com>
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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I noticed that if I use dd to read the set_ftrace_filter file that the first
hash command is repeated.
# cd /sys/kernel/debug/tracing
# echo schedule > set_ftrace_filter
# echo do_IRQ >> set_ftrace_filter
# echo schedule:traceoff >> set_ftrace_filter
# echo do_IRQ:traceoff >> set_ftrace_filter
# cat set_ftrace_filter
schedule
do_IRQ
schedule:traceoff:unlimited
do_IRQ:traceoff:unlimited
# dd if=set_ftrace_filter bs=1
schedule
do_IRQ
schedule:traceoff:unlimited
schedule:traceoff:unlimited
do_IRQ:traceoff:unlimited
98+0 records in
98+0 records out
98 bytes copied, 0.00265011 s, 37.0 kB/s
This is due to the way t_start() calls t_next() as well as the seq_file
calls t_next() and the state is slightly different between the two. Namely,
t_start() will call t_next() with a local "pos" variable.
By separating out the function listing from t_next() into its own function,
we can have better control of outputting the functions and the hash of
triggers. This simplifies the code.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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If all functions are enabled, there's a comment displayed in the file to
denote that:
# cd /sys/kernel/debug/tracing
# cat set_ftrace_filter
#### all functions enabled ####
If a function trigger is set, those are displayed as well:
# echo schedule:traceoff >> /debug/tracing/set_ftrace_filter
# cat set_ftrace_filter
#### all functions enabled ####
schedule:traceoff:unlimited
But if you read that file with dd, the output can change:
# dd if=/debug/tracing/set_ftrace_filter bs=1
#### all functions enabled ####
32+0 records in
32+0 records out
32 bytes copied, 7.0237e-05 s, 456 kB/s
This is because the "pos" variable is updated for the comment, but func_pos
is not. "func_pos" is used by the triggers (or hashes) to know how many
functions were printed and it bases its index from the pos - func_pos.
func_pos should be 1 to count for the comment printed. But since it is not,
t_hash_start() thinks that one trigger was already printed.
The cat gets to t_hash_start() via t_next() and not t_start() which updates
both pos and func_pos.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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The loop in t_start() of calling t_next() will call t_hash_start() if the
pos is beyond the functions and enters the hash items. There's no reason to
check if p is NULL and call t_hash_start(), as that would be redundant.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Instead of testing if the hash to use is the filter_hash or the notrace_hash
at each iteration, do the test at open, and set the iter->hash to point to
the corresponding filter or notrace hash. Then use that directly instead of
testing which hash needs to be used each iteration.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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