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* tracing: Remove locking trace_types_lock from tracing_reset_all_online_cpus()Steven Rostedt (Red Hat)2013-07-261-2/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | Commit a82274151af "tracing: Protect ftrace_trace_arrays list in trace_events.c" added taking the trace_types_lock mutex in trace_events.c as there were several locations that needed it for protection. Unfortunately, it also encapsulated a call to tracing_reset_all_online_cpus() which also takes the trace_types_lock, causing a deadlock. This happens when a module has tracepoints and has been traced. When the module is removed, the trace events module notifier will grab the trace_types_lock, do a bunch of clean ups, and also clears the buffer by calling tracing_reset_all_online_cpus. This doesn't happen often which explains why it wasn't caught right away. Commit a82274151af was marked for stable, which means this must be sent to stable too. Link: http://lkml.kernel.org/r/51EEC646.7070306@broadcom.com Reported-by: Arend van Spril <arend@broadcom.com> Tested-by: Arend van Spriel <arend@broadcom.com> Cc: Alexander Z Lam <azl@google.com> Cc: Vaibhav Nagarnaik <vnagarnaik@google.com> Cc: David Sharp <dhsharp@google.com> Cc: stable@vger.kernel.org # 3.10 Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* ftrace: Add check for NULL regs if ops has SAVE_REGS setSteven Rostedt (Red Hat)2013-07-241-4/+14
| | | | | | | | | | | | | | | | | | | If a ftrace ops is registered with the SAVE_REGS flag set, and there's already a ops registered to one of its functions but without the SAVE_REGS flag, there's a small race window where the SAVE_REGS ops gets added to the list of callbacks to call for that function before the callback trampoline gets set to save the regs. The problem is, the function is not currently saving regs, which opens a small race window where the ops that is expecting regs to be passed to it, wont. This can cause a crash if the callback were to reference the regs, as the SAVE_REGS guarantees that regs will be set. To fix this, we add a check in the loop case where it checks if the ops has the SAVE_REGS flag set, and if so, it will ignore it if regs is not set. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* tracing: Kill trace_cpu struct/membersOleg Nesterov2013-07-242-29/+0
| | | | | | | | | | | | | | After the previous changes trace_array_cpu->trace_cpu and trace_array->trace_cpu becomes write-only. Remove these members and kill "struct trace_cpu" as well. As a side effect this also removes memset(per_cpu_memory, 0). It was not needed, alloc_percpu() returns zero-filled memory. Link: http://lkml.kernel.org/r/20130723152613.GA23741@redhat.com Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* tracing: Change tracing_fops/snapshot_fops to rely on tracing_get_cpu()Oleg Nesterov2013-07-241-28/+22
| | | | | | | | | | | | | | | | | tracing_open() and tracing_snapshot_open() are racy, the memory inode->i_private points to can be already freed. Convert these last users of "inode->i_private == trace_cpu" to use "i_private = trace_array" and rely on tracing_get_cpu(). v2: incorporate the fix from Steven, tracing_release() must not blindly dereference file->private_data unless we know that the file was opened for reading. Link: http://lkml.kernel.org/r/20130723152610.GA23737@redhat.com Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* tracing: Change tracing_entries_fops to rely on tracing_get_cpu()Oleg Nesterov2013-07-241-37/+12
| | | | | | | | | | | | | | | | | | | | | | tracing_open_generic_tc() is racy, the memory inode->i_private points to can be already freed. 1. Change its last user, tracing_entries_fops, to use tracing_*_generic_tr() instead. 2. Change debugfs_create_file("buffer_size_kb", data) callers to pass "data = tr". 3. Change tracing_entries_read() and tracing_entries_write() to use tracing_get_cpu(). 4. Kill the no longer used tracing_open_generic_tc() and tracing_release_generic_tc(). Link: http://lkml.kernel.org/r/20130723152606.GA23730@redhat.com Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* tracing: Change tracing_stats_fops to rely on tracing_get_cpu()Oleg Nesterov2013-07-241-7/+6
| | | | | | | | | | | | | | | | | tracing_open_generic_tc() is racy, the memory inode->i_private points to can be already freed. 1. Change one of its users, tracing_stats_fops, to use tracing_*_generic_tr() instead. 2. Change trace_create_cpu_file("stats", data) to pass "data = tr". 3. Change tracing_stats_read() to use tracing_get_cpu(). Link: http://lkml.kernel.org/r/20130723152603.GA23727@redhat.com Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* tracing: Change tracing_buffers_fops to rely on tracing_get_cpu()Oleg Nesterov2013-07-241-5/+4
| | | | | | | | | | | | | | | | tracing_buffers_open() is racy, the memory inode->i_private points to can be already freed. Change debugfs_create_file("trace_pipe_raw", data) caller to pass "data = tr", tracing_buffers_open() can use tracing_get_cpu(). Change debugfs_create_file("snapshot_raw_fops", data) caller too, this file uses tracing_buffers_open/release. Link: http://lkml.kernel.org/r/20130723152600.GA23720@redhat.com Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* tracing: Change tracing_pipe_fops() to rely on tracing_get_cpu()Oleg Nesterov2013-07-241-9/+7
| | | | | | | | | | | | | tracing_open_pipe() is racy, the memory inode->i_private points to can be already freed. Change debugfs_create_file("trace_pipe", data) callers to to pass "data = tr", tracing_open_pipe() can use tracing_get_cpu(). Link: http://lkml.kernel.org/r/20130723152557.GA23717@redhat.com Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* tracing: Introduce trace_create_cpu_file() and tracing_get_cpu()Oleg Nesterov2013-07-241-14/+36
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Every "file_operations" used by tracing_init_debugfs_percpu is buggy. f_op->open/etc does: 1. struct trace_cpu *tc = inode->i_private; struct trace_array *tr = tc->tr; 2. trace_array_get(tr) or fail; 3. do_something(tc); But tc (and tr) can be already freed before trace_array_get() is called. And it doesn't matter whether this file is per-cpu or it was created by init_tracer_debugfs(), free_percpu() or kfree() are equally bad. Note that even 1. is not safe, the freed memory can be unmapped. But even if it was safe trace_array_get() can wrongly succeed if we also race with the next new_instance_create() which can re-allocate the same tr, or tc was overwritten and ->tr points to the valid tr. In this case 3. uses the freed/reused memory. Add the new trivial helper, trace_create_cpu_file() which simply calls trace_create_file() and encodes "cpu" in "struct inode". Another helper, tracing_get_cpu() will be used to read cpu_nr-or-RING_BUFFER_ALL_CPUS. The patch abuses ->i_cdev to encode the number, it is never used unless the file is S_ISCHR(). But we could use something else, say, i_bytes or even ->d_fsdata. In any case this hack is hidden inside these 2 helpers, it would be trivial to change them if needed. This patch only changes tracing_init_debugfs_percpu() to use the new trace_create_cpu_file(), the next patches will change file_operations. Note: tracing_get_cpu(inode) is always safe but you can't trust the result unless trace_array_get() was called, without trace_types_lock which acts as a barrier it can wrongly return RING_BUFFER_ALL_CPUS. Link: http://lkml.kernel.org/r/20130723152554.GA23710@redhat.com Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* tracing: Kill the unbalanced tr->ref++ in tracing_buffers_open()Oleg Nesterov2013-07-191-2/+0
| | | | | | | | | | | | | | | | | | | | | tracing_buffers_open() does trace_array_get() and then it wrongly inrcements tr->ref again under trace_types_lock. This means that every caller leaks trace_array: # cd /sys/kernel/debug/tracing/ # mkdir instances/X # true < instances/X/per_cpu/cpu0/trace_pipe_raw # rmdir instances/X rmdir: failed to remove `instances/X': Device or resource busy Link: http://lkml.kernel.org/r/20130719153644.GA18899@redhat.com Cc: Ingo Molnar <mingo@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: stable@vger.kernel.org # 3.10 Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* tracing: Kill trace_array->waiterOleg Nesterov2013-07-191-1/+0
| | | | | | | | | | Trivial. trace_array->waiter has no users since 6eaaa5d5 "tracing/core: use appropriate waiting on trace_pipe". Link: http://lkml.kernel.org/r/20130719142036.GA1594@redhat.com Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* tracing: Do not (ab)use trace_seq in event_id_read()Oleg Nesterov2013-07-191-13/+4
| | | | | | | | | | | | | | | | | | event_id_read() has no reason to kmalloc "struct trace_seq" (more than PAGE_SIZE!), it can use a small buffer instead. Note: "if (*ppos) return 0" looks strange and even wrong, simple_read_from_buffer() handles ppos != 0 case corrrectly. And it seems that almost every user of trace_seq in this file should be converted too. Unless you use seq_open(), trace_seq buys nothing compared to the raw buffer, but it needs a bit more memory and code. Link: http://lkml.kernel.org/r/20130718184712.GA4786@redhat.com Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* tracing: Simplify the iteration logic in f_start/f_nextOleg Nesterov2013-07-191-38/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | f_next() looks overcomplicated, and it is not strictly correct even if this doesn't matter. Say, FORMAT_FIELD_SEPERATOR should not return NULL (means EOF) if trace_get_fields() returns an empty list, we should simply advance to FORMAT_PRINTFMT as we do when we find the end of list. 1. Change f_next() to return "struct list_head *" rather than "ftrace_event_field *", and change f_show() to do list_entry(). This simplifies the code a bit, only f_show() needs to know about ftrace_event_field, and f_next() can play with ->prev directly 2. Change f_next() to not play with ->prev / return inside the switch() statement. It can simply set node = head/common_head, the prev-or-advance-to-the-next-magic below does all work. While at it. f_start() looks overcomplicated too. I don't think *pos == 0 makes sense as a separate case, just change this code to do "while" instead of "do/while". The patch also moves f_start() down, close to f_stop(). This is purely cosmetic, just to make the locking added by the next patch more clear/visible. Link: http://lkml.kernel.org/r/20130718184710.GA4783@redhat.com Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* tracing: Add ref_data to function and fgraph tracer structsSteven Rostedt (Red Hat)2013-07-193-2/+11
| | | | | | | | | | | | | | | | | | | | The selftest for function and function graph tracers are defined as __init, as they are only executed at boot up. The "tracer" structs that are associated to those tracers are not setup as __init as they are used after boot. To stop mismatch warnings, those structures need to be annotated with __ref_data. Currently, the tracer structures are defined to __read_mostly, as they do not really change. But in the future they should be converted to consts, but that will take a little work because they have a "next" pointer that gets updated when they are registered. That will have to wait till the next major release. Link: http://lkml.kernel.org/r/1373596735.17876.84.camel@gandalf.local.home Reported-by: kbuild test robot <fengguang.wu@intel.com> Reported-by: Chen Gang <gang.chen@asianux.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* tracing: Miscellaneous fixes for trace_array ref countingAlexander Z Lam2013-07-192-8/+37
| | | | | | | | | | | | | | Some error paths did not handle ref counting properly, and some trace files need ref counting. Link: http://lkml.kernel.org/r/1374171524-11948-1-git-send-email-azl@google.com Cc: stable@vger.kernel.org # 3.10 Cc: Vaibhav Nagarnaik <vnagarnaik@google.com> Cc: David Sharp <dhsharp@google.com> Cc: Alexander Z Lam <lambchop468@gmail.com> Signed-off-by: Alexander Z Lam <azl@google.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* tracing: Fix error handling to ensure instances can always be removedAlexander Z Lam2013-07-191-1/+3
| | | | | | | | | | | | | | | | | Remove debugfs directories for tracing instances during creation if an error occurs causing the trace_array for that instance to not be added to ftrace_trace_arrays. If the directory continues to exist after the error, it cannot be removed because the respective trace_array is not in ftrace_trace_arrays. Link: http://lkml.kernel.org/r/1373502874-1706-2-git-send-email-azl@google.com Cc: stable@vger.kernel.org # 3.10 Cc: Vaibhav Nagarnaik <vnagarnaik@google.com> Cc: David Sharp <dhsharp@google.com> Cc: Alexander Z Lam <lambchop468@gmail.com> Signed-off-by: Alexander Z Lam <azl@google.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* tracing/kprobe: Wait for disabling all running kprobe handlersMasami Hiramatsu2013-07-191-6/+17
| | | | | | | | | | | | | | Wait for disabling all running kprobe handlers when a kprobe event is disabled, since the caller, trace_remove_event_call() supposes that a removing event is disabled completely by disabling the event. With this change, ftrace can ensure that there is no running event handlers after disabling it. Link: http://lkml.kernel.org/r/20130709093526.20138.93100.stgit@mhiramat-M0-7522 Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* tracing/perf: Move the PERF_MAX_TRACE_SIZE check into perf_trace_buf_prepare()Oleg Nesterov2013-07-194-20/+4
| | | | | | | | | | | | | | | | | | | | Every perf_trace_buf_prepare() caller does WARN_ONCE(size > PERF_MAX_TRACE_SIZE, message) and "message" is almost the same. Shift this WARN_ONCE() into perf_trace_buf_prepare(). This changes the meaning of _ONCE, but I think this is fine. - 4947014 2932448 10104832 17984294 1126b26 vmlinux + 4948422 2932448 10104832 17985702 11270a6 vmlinux on my build. Link: http://lkml.kernel.org/r/20130617170211.GA19813@redhat.com Acked-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* tracing/syscall: Avoid perf_trace_buf_*() if sys_data->perf_events is emptyOleg Nesterov2013-07-191-4/+8
| | | | | | | | | | | | perf_trace_buf_prepare() + perf_trace_buf_submit(head, task => NULL) make no sense if hlist_empty(head). Change perf_syscall_enter/exit() to check sys_data->{enter,exit}_event->perf_events beforehand. Link: http://lkml.kernel.org/r/20130617170207.GA19806@redhat.com Acked-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* tracing/function: Avoid perf_trace_buf_*() if event_function.perf_events is ↵Oleg Nesterov2013-07-191-2/+4
| | | | | | | | | | | | | | empty perf_trace_buf_prepare() + perf_trace_buf_submit(head, task => NULL) make no sense if hlist_empty(head). Change perf_ftrace_function_call() to check event_function.perf_events beforehand. Link: http://lkml.kernel.org/r/20130617170204.GA19803@redhat.com Acked-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* tracing: Typo fix on ring buffer commentszhangwei(Jovi)2013-07-191-7/+9
| | | | | | | | | | | | | There have some mismatch between comments with real function name, update it. This patch also add some missed function arguments description. Link: http://lkml.kernel.org/r/51E3B3B2.4080307@huawei.com Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* tracing: Use trace_seq_puts()/trace_seq_putc() where possiblezhangwei(Jovi)2013-07-196-45/+45
| | | | | | | | | | | For string without format specifiers, use trace_seq_puts() or trace_seq_putc(). Link: http://lkml.kernel.org/r/51E3B3AC.1000605@huawei.com Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com> [ fixed a trace_seq_putc(s, " ") to trace_seq_putc(s, ' ') ] Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* tracing: Use correct config guard CONFIG_STACK_TRACERzhangwei(Jovi)2013-07-151-2/+2
| | | | | | | | | | We should use CONFIG_STACK_TRACER to guard readme text of stack tracer related file, not CONFIG_STACKTRACE. Link: http://lkml.kernel.org/r/51E3B3A2.8080609@huawei.com Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* Merge tag 'trace-3.11' of ↵Linus Torvalds2013-07-1111-265/+640
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull tracing changes from Steven Rostedt: "The majority of the changes here are cleanups for the large changes that were added to 3.10, which includes several bug fixes that have been marked for stable. As for new features, there were a few, but nothing to write to LWN about. These include: New function trigger called "dump" and "cpudump" that will cause ftrace to dump its buffer to the console when the function is called. The difference between "dump" and "cpudump" is that "dump" will dump the entire contents of the ftrace buffer, where as "cpudump" will only dump the contents of the ftrace buffer for the CPU that called the function. Another small enhancement is a new sysctl switch called "traceoff_on_warning" which, when enabled, will disable tracing if any WARN_ON() is triggered. This is useful if you want to debug what caused a warning and do not want to risk losing your trace data by the ring buffer overwriting the data before you can disable it. There's also a kernel command line option that will make this enabled at boot up called the same thing" * tag 'trace-3.11' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (34 commits) tracing: Make tracing_open_generic_{tr,tc}() static tracing: Remove ftrace() function tracing: Remove TRACE_EVENT_TYPE enum definition tracing: Make tracer_tracing_{off,on,is_on}() static tracing: Fix irqs-off tag display in syscall tracing uprobes: Fix return value in error handling path tracing: Fix race between deleting buffer and setting events tracing: Add trace_array_get/put() to event handling tracing: Get trace_array ref counts when accessing trace files tracing: Add trace_array_get/put() to handle instance refs better tracing: Protect ftrace_trace_arrays list in trace_events.c tracing: Make trace_marker use the correct per-instance buffer ftrace: Do not run selftest if command line parameter is set tracing/kprobes: Don't pass addr=ip to perf_trace_buf_submit() tracing: Use flag buffer_disabled for irqsoff tracer tracing/kprobes: Turn trace_probe->files into list_head tracing: Fix disabling of soft disable tracing: Add missing syscall_metadata comment tracing: Simplify code for showing of soft disabled flag tracing/kprobes: Kill probe_enable_lock ...
| * tracing: Make tracing_open_generic_{tr,tc}() staticSteven Rostedt (Red Hat)2013-07-031-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | I have patches that will use tracing_open_generic_tr/tc() in other files, but as they are not ready to be merged yet, and Fengguang Wu's sparse scripts pointed out that these functions were not declared anywhere, I'll make them static for now. When these functions are required to be used elsewhere, I'll remove the static then. Reported-by: kbuild test robot <fengguang.wu@intel.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * tracing: Remove ftrace() functionzhangwei(Jovi)2013-07-032-14/+0
| | | | | | | | | | | | | | | | | | | | The only caller of function ftrace(...) was removed a long time ago, so remove the function body as well. Link: http://lkml.kernel.org/r/1365564393-10972-10-git-send-email-jovi.zhangwei@huawei.com Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * tracing: Remove TRACE_EVENT_TYPE enum definitionzhangwei(Jovi)2013-07-031-6/+0
| | | | | | | | | | | | | | | | | | TRACE_EVENT_TYPE enum is not used at present, remove it. Link: http://lkml.kernel.org/r/1365564393-10972-8-git-send-email-jovi.zhangwei@huawei.com Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * tracing: Make tracer_tracing_{off,on,is_on}() staticSteven Rostedt (Red Hat)2013-07-031-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | I have patches that will use tracer_tracing_on/off/is_on() in other files, but as they are not ready to be merged yet, and Fengguang Wu's sparse scripts pointed out that these functions were not declared anywhere, I'll make them static for now. When these functions are required to be used elsewhere, I'll remove the static then. Reported-by: kbuild test robot <fengguang.wu@intel.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * tracing: Fix irqs-off tag display in syscall tracingzhangwei(Jovi)2013-07-031-4/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | All syscall tracing irqs-off tags are wrong, the syscall enter entry doesn't disable irqs. [root@jovi tracing]#echo "syscalls:sys_enter_open" > set_event [root@jovi tracing]# cat trace # tracer: nop # # entries-in-buffer/entries-written: 13/13 #P:2 # # _-----=> irqs-off # / _----=> need-resched # | / _---=> hardirq/softirq # || / _--=> preempt-depth # ||| / delay # TASK-PID CPU# |||| TIMESTAMP FUNCTION # | | | |||| | | irqbalance-513 [000] d... 56115.496766: sys_open(filename: 804e1a6, flags: 0, mode: 1b6) irqbalance-513 [000] d... 56115.497008: sys_open(filename: 804e1bb, flags: 0, mode: 1b6) sendmail-771 [000] d... 56115.827982: sys_open(filename: b770e6d1, flags: 0, mode: 1b6) The reason is syscall tracing doesn't record irq_flags into buffer. The proper display is: [root@jovi tracing]#echo "syscalls:sys_enter_open" > set_event [root@jovi tracing]# cat trace # tracer: nop # # entries-in-buffer/entries-written: 14/14 #P:2 # # _-----=> irqs-off # / _----=> need-resched # | / _---=> hardirq/softirq # || / _--=> preempt-depth # ||| / delay # TASK-PID CPU# |||| TIMESTAMP FUNCTION # | | | |||| | | irqbalance-514 [001] .... 46.213921: sys_open(filename: 804e1a6, flags: 0, mode: 1b6) irqbalance-514 [001] .... 46.214160: sys_open(filename: 804e1bb, flags: 0, mode: 1b6) <...>-920 [001] .... 47.307260: sys_open(filename: 4e82a0c5, flags: 80000, mode: 0) Link: http://lkml.kernel.org/r/1365564393-10972-3-git-send-email-jovi.zhangwei@huawei.com Cc: stable@vger.kernel.org # 2.6.35 Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * uprobes: Fix return value in error handling pathzhangwei(Jovi)2013-07-031-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When wrong argument is passed into uprobe_events it does not return an error: [root@jovi tracing]# echo 'p:myprobe /bin/bash' > uprobe_events [root@jovi tracing]# The proper response is: [root@jovi tracing]# echo 'p:myprobe /bin/bash' > uprobe_events -bash: echo: write error: Invalid argument Link: http://lkml.kernel.org/r/51B964FF.5000106@huawei.com Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: <srikar@linux.vnet.ibm.com> Cc: stable@vger.kernel.org # 3.5+ Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * tracing: Fix race between deleting buffer and setting eventsSteven Rostedt (Red Hat)2013-07-031-6/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | While analyzing the code, I discovered that there's a potential race between deleting a trace instance and setting events. There are a few races that can occur if events are being traced as the buffer is being deleted. Mostly the problem comes with freeing the descriptor used by the trace event callback. To prevent problems like this, the events are disabled before the buffer is deleted. The problem with the current solution is that the event_mutex is let go between disabling the events and freeing the files, which means that the events could be enabled again while the freeing takes place. Cc: stable@vger.kernel.org # 3.10 Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * tracing: Add trace_array_get/put() to event handlingSteven Rostedt (Red Hat)2013-07-022-4/+54
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit a695cb58162 "tracing: Prevent deleting instances when they are being read" tried to fix a race between deleting a trace instance and reading contents of a trace file. But it wasn't good enough. The following could crash the kernel: # cd /sys/kernel/debug/tracing/instances # ( while :; do mkdir foo; rmdir foo; done ) & # ( while :; do echo 1 > foo/events/sched/sched_switch 2> /dev/null; done ) & Luckily this can only be done by root user, but it should be fixed regardless. The problem is that a delete of the file can happen after the write to the event is opened, but before the enabling happens. The solution is to make sure the trace_array is available before succeeding in opening for write, and incerment the ref counter while opened. Now the instance can be deleted when the events are writing to the buffer, but the deletion of the instance will disable all events before the instance is actually deleted. Cc: stable@vger.kernel.org # 3.10 Reported-by: Alexander Lam <azl@google.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * tracing: Get trace_array ref counts when accessing trace filesSteven Rostedt (Red Hat)2013-07-021-9/+112
| | | | | | | | | | | | | | | | | | When a trace file is opened that may access a trace array, it must increment its ref count to prevent it from being deleted. Cc: stable@vger.kernel.org # 3.10 Reported-by: Alexander Lam <azl@google.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * tracing: Add trace_array_get/put() to handle instance refs betterSteven Rostedt (Red Hat)2013-07-021-18/+65
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit a695cb58162 "tracing: Prevent deleting instances when they are being read" tried to fix a race between deleting a trace instance and reading contents of a trace file. But it wasn't good enough. The following could crash the kernel: # cd /sys/kernel/debug/tracing/instances # ( while :; do mkdir foo; rmdir foo; done ) & # ( while :; do cat foo/trace &> /dev/null; done ) & Luckily this can only be done by root user, but it should be fixed regardless. The problem is that a delete of the file can happen after the reader starts to open the file but before it grabs the trace_types_mutex. The solution is to validate the trace array before using it. If the trace array does not exist in the list of trace arrays, then it returns -ENODEV. There's a possibility that a trace_array could be deleted and a new one created and the open would open its file instead. But that is very minor as it will just return the data of the new trace array, it may confuse the user but it will not crash the system. As this can only be done by root anyway, the race will only occur if root is deleting what its trying to read at the same time. Cc: stable@vger.kernel.org # 3.10 Reported-by: Alexander Lam <azl@google.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * tracing: Protect ftrace_trace_arrays list in trace_events.cAlexander Z Lam2013-07-023-2/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | There are multiple places where the ftrace_trace_arrays list is accessed in trace_events.c without the trace_types_lock held. Link: http://lkml.kernel.org/r/1372732674-22726-1-git-send-email-azl@google.com Cc: Vaibhav Nagarnaik <vnagarnaik@google.com> Cc: David Sharp <dhsharp@google.com> Cc: Alexander Z Lam <lambchop468@gmail.com> Cc: stable@vger.kernel.org # 3.10 Signed-off-by: Alexander Z Lam <azl@google.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * tracing: Make trace_marker use the correct per-instance bufferAlexander Z Lam2013-07-021-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The trace_marker file was present for each new instance created, but it added the trace mark to the global trace buffer instead of to the instance's buffer. Link: http://lkml.kernel.org/r/1372717885-4543-2-git-send-email-azl@google.com Cc: David Sharp <dhsharp@google.com> Cc: Vaibhav Nagarnaik <vnagarnaik@google.com> Cc: Alexander Z Lam <lambchop468@gmail.com> Cc: stable@vger.kernel.org # 3.10 Signed-off-by: Alexander Z Lam <azl@google.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * ftrace: Do not run selftest if command line parameter is setSteven Rostedt (Red Hat)2013-07-023-2/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If the kernel command line ftrace filter parameters are set (ftrace_filter or ftrace_notrace), force the function self test to pass, with a warning why it was forced. If the user adds a filter to the kernel command line, it is assumed that they know what they are doing, and the self test should just not run instead of failing (which disables function tracing) or clearing the filter, as that will probably annoy the user. If the user wants the selftest to run, the message will tell them why it did not. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * tracing/kprobes: Don't pass addr=ip to perf_trace_buf_submit()Oleg Nesterov2013-07-021-4/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | kprobe_perf_func() and kretprobe_perf_func() pass addr=ip to perf_trace_buf_submit() for no reason. This sets perf_sample_data->addr for PERF_SAMPLE_ADDR, we already have perf_sample_data->ip initialized if PERF_SAMPLE_IP. Link: http://lkml.kernel.org/r/20130620173811.GA13161@redhat.com Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * tracing: Use flag buffer_disabled for irqsoff tracerSteven Rostedt (Red Hat)2013-07-022-33/+72
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If the ring buffer is disabled and the irqsoff tracer records a trace it will clear out its buffer and lose the data it had previously recorded. Currently there's a callback when writing to the tracing_of file, but if tracing is disabled via the function tracer trigger, it will not inform the irqsoff tracer to stop recording. By using the "mirror" flag (buffer_disabled) in the trace_array, that keeps track of the status of the trace_array's buffer, it gives the irqsoff tracer a fast way to know if it should record a new trace or not. The flag may be a little behind the real state of the buffer, but it should not affect the trace too much. It's more important for the irqsoff tracer to be fast. Reported-by: Dave Jones <davej@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * tracing/kprobes: Turn trace_probe->files into list_headOleg Nesterov2013-07-021-101/+37
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | I think that "ftrace_event_file *trace_probe[]" complicates the code for no reason, turn it into list_head to simplify the code. enable_trace_probe() no longer needs synchronize_sched(). This needs the extra sizeof(list_head) memory for every attached ftrace_event_file, hopefully not a problem in this case. Link: http://lkml.kernel.org/r/20130620173814.GA13165@redhat.com Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * tracing: Fix disabling of soft disableTom Zanussi2013-07-021-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The comment on the soft disable 'disable' case of __ftrace_event_enable_disable() states that the soft disable bit should be cleared in that case, but currently only the soft mode bit is actually cleared. This essentially leaves the standard non-soft-enable enable/disable paths as the only way to clear the soft disable flag, but the soft disable bit should also be cleared when removing a trigger with '!'. Also, the SOFT_DISABLED bit should never be set if SOFT_MODE is cleared. This fixes the above discrepancies. Link: http://lkml.kernel.org/r/b9c68dd50bc07019e6c67d3f9b29be4ef1b2badb.1372479499.git.tom.zanussi@linux.intel.com Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * tracing: Simplify code for showing of soft disabled flagTom Zanussi2013-07-021-10/+10
| | | | | | | | | | | | | | | | | | | | | | Rather than enumerating each permutation, build the enable state string up from the combination of states. This also allows for the simpler addition of more states. Link: http://lkml.kernel.org/r/9aff5af6dee2f5a40ca30df41c39d5f33e998d7a.1372479499.git.tom.zanussi@linux.intel.com Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * tracing/kprobes: Kill probe_enable_lockOleg Nesterov2013-07-021-23/+20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | enable_trace_probe() and disable_trace_probe() should not worry about serialization, the caller (perf_trace_init or __ftrace_set_clr_event) holds event_mutex. They are also called by kprobe_trace_self_tests_init(), but this __init function can't race with itself or trace_events.c And note that this code depended on event_mutex even before 41a7dd420c which introduced probe_enable_lock. In fact it assumes that the caller kprobe_register() can never race with itself. Otherwise, say, tp->flags manipulations are racy. Link: http://lkml.kernel.org/r/20130620173809.GA13158@redhat.com Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * tracing/kprobes: Avoid perf_trace_buf_*() if ->perf_events is emptyOleg Nesterov2013-07-021-4/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | perf_trace_buf_prepare() + perf_trace_buf_submit() make no sense if this task/CPU has no active counters. Change kprobe_perf_func() and kretprobe_perf_func() to check call->perf_events beforehand and return if this list is empty. For example, "perf record -e some_probe -p1". Only /sbin/init will report, all other threads which hit the same probe will do perf_trace_buf_prepare/perf_trace_buf_submit just to realize that nobody wants perf_swevent_event(). Link: http://lkml.kernel.org/r/20130620173806.GA13151@redhat.com Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * tracing: Failed to create system directorySteven Rostedt2013-07-021-6/+35
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Running the following: # cd /sys/kernel/debug/tracing # echo p:i do_sys_open > kprobe_events # echo p:j schedule >> kprobe_events # cat kprobe_events p:kprobes/i do_sys_open p:kprobes/j schedule # echo p:i do_sys_open >> kprobe_events # cat kprobe_events p:kprobes/j schedule p:kprobes/i do_sys_open # ls /sys/kernel/debug/tracing/events/kprobes/ enable filter j Notice that the 'i' is missing from the kprobes directory. The console produces: "Failed to create system directory kprobes" This is because kprobes passes in a allocated name for the system and the ftrace event subsystem saves off that name instead of creating a duplicate for it. But the kprobes may free the system name making the pointer to it invalid. This bug was introduced by 92edca073c37 "tracing: Use direct field, type and system names" which switched from using kstrdup() on the system name in favor of just keeping apointer to it, as the internal ftrace event system names are static and exist for the life of the computer being booted. Instead of reverting back to duplicating system names again, we can use core_kernel_data() to determine if the passed in name was allocated or static. Then use the MSB of the ref_count to be a flag to keep track if the name was allocated or not. Then we can still save from having to duplicate strings that will always exist, but still copy the ones that may be freed. Cc: stable@vger.kernel.org # 3.10 Reported-by: "zhangwei(Jovi)" <jovi.zhangwei@huawei.com> Reported-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * ftrace: Fix stddev calculation in function profilerJuri Lelli2013-06-201-2/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | When FUNCTION_GRAPH_TRACER is enabled, ftrace can profile kernel functions and print basic statistics about them. Unfortunately, running stddev calculation is wrong. This patch corrects it implementing Welford’s method: s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2) . Link: http://lkml.kernel.org/r/1371031398-24048-1-git-send-email-juri.lelli@gmail.com Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Signed-off-by: Juri Lelli <juri.lelli@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * tracing/kprobes: Remove unnecessary checking of trace_probe_is_enabledzhangwei(Jovi)2013-06-201-2/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since tp->flags assignment was moved into function enable_trace_probe(), there is no need to use trace_probe_is_enabled to check flags in the same function. Remove the unnecessary checking. Link: http://lkml.kernel.org/r/51BA7B9E.3040807@huawei.com Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * tracing: Disable tracing on warningSteven Rostedt (Red Hat)2013-06-201-0/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add a traceoff_on_warning option in both the kernel command line as well as a sysctl option. When set, any WARN*() function that is hit will cause the tracing_on variable to be cleared, which disables writing to the ring buffer. This is useful especially when tracing a bug with function tracing. When a warning is hit, the print caused by the warning can flood the trace with the functions that producing the output for the warning. This can make the resulting trace useless by either hiding where the bug happened, or worse, by overflowing the buffer and losing the trace of the bug totally. Acked-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * tracing: Add binary '&' filter for eventsSteven Rostedt2013-06-201-0/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There are some cases when filtering on a set flag of a field of a tracepoint is useful. But currently the only filtering commands for numbered fields is ==, !=, <, <=, >, >=. This does not help when you just want to trace if a specific flag is set. For example: > # sudo trace-cmd record -e brcmfmac:brcmf_dbg -f 'level & 0x40000' > disable all > enable brcmfmac:brcmf_dbg > path = /sys/kernel/debug/tracing/events/brcmfmac/brcmf_dbg/enable > (level & 0x40000) > ^ > parse_error: Invalid operator > When trying to trace brcmf_dbg when level has its 1 << 18 bit set, the filter fails to perform. By allowing a binary '&' operation, this gives the user the ability to test a bit. Note, a binary '|' is not added, as it doesn't make sense as fields must be compared to constants (for now), and ORing a constant will always return true. Link: http://lkml.kernel.org/r/1371057385.9844.261.camel@gandalf.local.home Suggested-by: Arend van Spriel <arend@broadcom.com> Tested-by: Arend van Spriel <arend@broadcom.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * tracing: Do not call kmem_cache_free() on allocation failureNamhyung Kim2013-06-121-6/+1
| | | | | | | | | | | | | | | | | | There's no point calling it when _alloc() failed. Link: http://lkml.kernel.org/r/1370585268-29169-1-git-send-email-namhyung@kernel.org Signed-off-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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