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* Merge branch 'tracing/fixes' of ↵Ingo Molnar2009-08-04
|\ | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing into tracing/urgent
| * tracing: Fix missing function_graph events when we splice_read from trace_pipeLai Jiangshan2009-07-28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | About a half events are missing when we splice_read from trace_pipe. They are unexpectedly consumed because we ignore the TRACE_TYPE_NO_CONSUME return value used by the function graph tracer when it needs to consume the events by itself to walk on the ring buffer. The same problem appears with ftrace_dump() Example of an output before this patch: 1) | ktime_get_real() { 1) 2.846 us | read_hpet(); 1) 4.558 us | } 1) 6.195 us | } After this patch: 0) | ktime_get_real() { 0) | getnstimeofday() { 0) 1.960 us | read_hpet(); 0) 3.597 us | } 0) 5.196 us | } The fix also applies on 2.6.30 Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: stable@kernel.org LKML-Reference: <4A6EEC52.90704@cn.fujitsu.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
| * tracing: Fix invalid function_graph entryLai Jiangshan2009-07-28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When print_graph_entry() computes a function call entry event, it needs to also check the next entry to guess if it matches the return event of the current function entry. In order to look at this next event, it needs to consume the current entry before going ahead in the ring buffer. However, if the current event that gets consumed is the last one in the ring buffer head page, the ring_buffer may reuse the page for writers. The consumed entry will then become invalid because of possible racy overwriting. Me must then handle this entry by making a copy of it. The fix also applies on 2.6.30 Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: stable@kernel.org LKML-Reference: <4A6EEAEC.3050508@cn.fujitsu.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
* | tracing: only truncate ftrace files when O_TRUNC is setSteven Rostedt2009-07-23
| | | | | | | | | | | | | | | | | | | | | | The current code will truncate the ftrace files contents if O_APPEND is not set and the file is opened in write mode. This is incorrect. It should only truncate the file if O_TRUNC is set. Otherwise if one of these files is opened by a C program with fopen "r+", it will incorrectly truncate the file. Reported-by: Jiri Olsa <jolsa@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* | tracing: show proper address for trace-printk formatSteven Rostedt2009-07-23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since the trace_printk may use pointers to the format fields in the buffer, they are exported via debugfs/tracing/printk_formats. This is used by utilities that read the ring buffer in binary format. It helps the utilities map the address of the format in the binary buffer to what the printf format looks like. Unfortunately, the way the output code works, it exports the address of the pointer to the format address, and not the format address itself. This makes the file totally useless in trying to figure out what format string a binary address belongs to. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* | tracing/stat: Fix seqfile memory leakLi Zefan2009-07-23
| | | | | | | | | | | | | | | | | | | | | | Every time we cat a trace_stat file, we leak memory allocated by seq_open(). Also fix memory leak in a failure path in tracing_stat_open(). Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> LKML-Reference: <4A67D92B.4060704@cn.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* | function-graph: Fix seqfile memory leakLi Zefan2009-07-23
| | | | | | | | | | | | | | | | | | Every time we cat set_graph_function, we leak memory allocated by seq_open(). Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> LKML-Reference: <4A67D907.2010500@cn.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* | trace_stack: Fix seqfile memory leakLi Zefan2009-07-23
|/ | | | | | | | Every time we cat stack_trace, we leak memory allocated by seq_open(). Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> LKML-Reference: <4A67D8E8.3020500@cn.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* tracing/function: Fix the return value of ftrace_trace_onoff_callback()Xiao Guangrong2009-07-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ftrace_trace_onoff_callback() will return an error even if we do the right operation, for example: # echo _spin_*:traceon:10 > set_ftrace_filter -bash: echo: write error: Invalid argument # cat set_ftrace_filter #### all functions enabled #### _spin_trylock_bh:traceon:count=10 _spin_unlock_irq:traceon:count=10 _spin_unlock_bh:traceon:count=10 _spin_lock_irq:traceon:count=10 _spin_unlock:traceon:count=10 _spin_trylock:traceon:count=10 _spin_unlock_irqrestore:traceon:count=10 _spin_lock_irqsave:traceon:count=10 _spin_lock_bh:traceon:count=10 _spin_lock:traceon:count=10 We want to set _spin_*:traceon:10 to set_ftrace_filter, it complains with "Invalid argument", but the operation is successful. This is because ftrace_process_regex() returns the number of functions that matched the pattern. If the number is not 0, this value is returned by ftrace_regex_write() whereas we want to return the number of bytes virtually written. Also the file offset pointer is not updated in this case. If the number of matched functions is lower than the number of bytes written by the user, this results to a reprocessing of the string given by the user with a lower size, leading to a malformed ftrace regex and then a -EINVAL returned. So, this patch fixes it by returning 0 if no error occured. The fix also applies on 2.6.30 Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com> Reviewed-by: Li Zefan <lizf@cn.fujitsu.com> Cc: stable@kernel.org Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
* tracing/function-profiler: do not free per cpu variable statSteven Rostedt2009-07-13
| | | | | | | | | | | | | | The per cpu variable stat is freeded if we fail to allocate a name on start up. This was due to stat at first being allocated in the initial design. But since then, it has become a static per cpu variable but the free on error was not removed. Also added __init annotation to the function that this is in. [ Impact: prevent possible memory corruption on low mem at boot up ] Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* headers: smp_lock.h reduxAlexey Dobriyan2009-07-12
| | | | | | | | | | | | | * Remove smp_lock.h from files which don't need it (including some headers!) * Add smp_lock.h to files which do need it * Make smp_lock.h include conditional in hardirq.h It's needed only for one kernel_locked() usage which is under CONFIG_PREEMPT This will make hardirq.h inclusion cheaper for every PREEMPT=n config (which includes allmodconfig/allyesconfig, BTW) Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* tracing: Fix trace_print_seq()Xiao Guangrong2009-07-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We will lose something if trace_seq->buffer[0] is 0, because the copy length is calculated by strlen() in seq_puts(), so using seq_write() instead of seq_puts(). There have a example: after reboot: # echo kmemtrace > current_tracer # echo 0 > options/kmem_minimalistic # cat trace # tracer: kmemtrace # # Nothing is exported, because the first byte of trace_seq->buffer[ ] is KMEMTRACE_USER_ALLOC. ( the value of KMEMTRACE_USER_ALLOC is zero, seeing kmemtrace_print_alloc_user() in kernel/trace/kmemtrace.c) Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Pekka Enberg <penberg@cs.helsinki.fi> Acked-by: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro> Cc: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <4A4B2351.5010300@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* tracing/fastboot: Document the need of initcall_debugLi Zefan2009-06-29
| | | | | | | | | | | To use boot tracer, one should pass initcall_debug as well as ftrace=initcall to the command line. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <4A48735E.9050002@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* trace_export: Repair missed fieldsLai Jiangshan2009-06-26
| | | | | | | | | | | Some fields for struct ftrace_graph_ret are missed when they are exported to user. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <4A448FB6.5000302@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* tracing: Fix stack tracer sysctl handlingLi Zefan2009-06-26
| | | | | | | | | | | | | | | | | | This made my machine completely frozen: # echo 1 > /proc/sys/kernel/stack_tracer_enabled # echo 2 > /proc/sys/kernel/stack_tracer_enabled The cause is register_ftrace_function() was called twice. Also fix ftrace_enabled sysctl, though seems nothing bad happened as I tested it. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <4A448D17.9010305@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* ftrace: Fix the output of profileLi Zefan2009-06-26
| | | | | | | | | | | The first entry of the ftrace profile was always skipped when reading trace_stat/functionX. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <4A443D59.4080307@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* ring-buffer: Make it generally availablePaul Mundt2009-06-25
| | | | | | | | | | | | | | | | | In hunting down the cause for the hwlat_detector ring buffer spew in my failed -next builds it became obvious that folks are now treating ring_buffer as something that is generic independent of tracing and thus, suitable for public driver consumption. Given that there are only a few minor areas in ring_buffer that have any reliance on CONFIG_TRACING or CONFIG_FUNCTION_TRACER, provide stubs for those and make it generally available. Signed-off-by: Paul Mundt <lethal@linux-sh.org> Cc: Jon Masters <jcm@jonmasters.org> Cc: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <20090625053012.GB19944@linux-sh.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* ftrace: Remove duplicate newlineLi Zefan2009-06-25
| | | | | | | | | | | | | | | | | | | | | | | Before: # echo 'sys_open:traceon:' > set_ftrace_filter # echo 'sys_close:traceoff:5' > set_ftrace_filter # cat set_ftrace_filter #### all functions enabled #### sys_open:traceon:unlimited sys_close:traceoff:count=0 After: # cat set_ftrace_filter #### all functions enabled #### sys_open:traceon:unlimited sys_close:traceoff:count=0 Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <4A4313A7.7030105@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* tracing: Fix trace_buf_size boot optionLi Zefan2009-06-24
| | | | | | | | | | | We should be able to specify [KMG] when setting trace_buf_size boot option, as documented in kernel-parameters.txt Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <4A41F2DB.4020102@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* ftrace: Fix t_hash_start()Li Zefan2009-06-24
| | | | | | | | | | | | | | | | | When the output of set_ftrace_filter is larger than PAGE_SIZE, t_hash_start() will be called the 2nd time, and then we start from the head of a hlist, which is wrong and causes some entries to be outputed twice. The worse is, if the hlist is large enough, reading set_ftrace_filter won't stop but in a dead loop. Reviewed-by: Liming Wang <liming.wang@windriver.com> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <4A41876E.2060407@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* ftrace: Don't manipulate @pos in t_start()Li Zefan2009-06-24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It's rather confusing that in t_start(), in some cases @pos is incremented, and in some cases it's decremented and then incremented. This patch rewrites t_start() in a much more general way. Thus we fix a bug that if ftrace_filtered == 1, functions have tracer hooks won't be printed, because the branch is always unreachable: static void *t_start(...) { ... if (!p) return t_hash_start(m, pos); return p; } Before: # echo 'sys_open' > /mnt/tracing/set_ftrace_filter # echo 'sys_write:traceon:4' >> /mnt/tracing/set_ftrace_filter sys_open After: # echo 'sys_open' > /mnt/tracing/set_ftrace_filter # echo 'sys_write:traceon:4' >> /mnt/tracing/set_ftrace_filter sys_open sys_write:traceon:count=4 Reviewed-by: Liming Wang <liming.wang@windriver.com> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <4A41874B.4090507@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* ftrace: Don't increment @pos in g_start()Li Zefan2009-06-24
| | | | | | | | | | | | | It's wrong to increment @pos in g_start(). It causes some entries lost when reading set_graph_function, if the output of the file is larger than PAGE_SIZE. Reviewed-by: Liming Wang <liming.wang@windriver.com> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <4A418738.7090401@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* tracing: Reset iterator in t_start()Li Zefan2009-06-24
| | | | | | | | | | | | | The iterator is m->private, but it's not reset to trace_types in t_start(). If the output is larger than PAGE_SIZE and t_start() is called the 2nd time, things will go wrong. Reviewed-by: Liming Wang <liming.wang@windriver.com> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <4A418728.5020506@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* trace_stat: Don't increment @pos in seq start()Li Zefan2009-06-24
| | | | | | | | | | | | | It's wrong to increment @pos in stat_seq_start(). It causes some stat entries lost when reading stat file, if the output of the file is larger than PAGE_SIZE. Reviewed-by: Liming Wang <liming.wang@windriver.com> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <4A418716.90209@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* tracing_bprintk: Don't increment @pos in t_start()Li Zefan2009-06-24
| | | | | | | | | | | | | | It's wrong to increment @pos in t_start(), otherwise we'll lose some entries when reading printk_formats, if the output is larger than PAGE_SIZE. Reported-by: Lai Jiangshan <laijs@cn.fujitsu.com> Reviewed-by: Liming Wang <liming.wang@windriver.com> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <4A4186FA.1020106@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* tracing/events: Don't increment @pos in s_start()Li Zefan2009-06-24
| | | | | | | | | | | | | | | | | | | | | | | | | | | While testing syscall tracepoints posted by Jason, I found 3 entries were missing when reading available_events. The output size of available_events is < 4 pages, which means we lost 1 entry per page. The cause is, it's wrong to increment @pos in s_start(). Actually there's another bug here -- reading avaiable_events/set_events can race with module unload: # cat available_events | s_start() | s_stop() | | # rmmod foo.ko s_start() | call = list_entry(m->private) | @call might be freed and accessing it will lead to crash. Reviewed-by: Liming Wang <liming.wang@windriver.com> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <4A4186DD.6090405@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* Merge branch 'tracing-fixes-for-linus' of ↵Linus Torvalds2009-06-20
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (24 commits) tracing/urgent: warn in case of ftrace_start_up inbalance tracing/urgent: fix unbalanced ftrace_start_up function-graph: add stack frame test function-graph: disable when both x86_32 and optimize for size are configured ring-buffer: have benchmark test print to trace buffer ring-buffer: do not grab locks in nmi ring-buffer: add locks around rb_per_cpu_empty ring-buffer: check for less than two in size allocation ring-buffer: remove useless compile check for buffer_page size ring-buffer: remove useless warn on check ring-buffer: use BUF_PAGE_HDR_SIZE in calculating index tracing: update sample event documentation tracing/filters: fix race between filter setting and module unload tracing/filters: free filter_string in destroy_preds() ring-buffer: use commit counters for commit pointer accounting ring-buffer: remove unused variable ring-buffer: have benchmark test handle discarded events ring-buffer: prevent adding write in discarded area tracing/filters: strloc should be unsigned short tracing/filters: operand can be negative ... Fix up kmemcheck-induced conflict in kernel/trace/ring_buffer.c manually
| * Merge branch 'tip/tracing/urgent-1' of ↵Ingo Molnar2009-06-20
| |\ | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into tracing/urgent
| | * function-graph: add stack frame testSteven Rostedt2009-06-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In case gcc does something funny with the stack frames, or the return from function code, we would like to detect that. An arch may implement passing of a variable that is unique to the function and can be saved on entering a function and can be tested when exiting the function. Usually the frame pointer can be used for this purpose. This patch also implements this for x86. Where it passes in the stack frame of the parent function, and will test that frame on exit. There was a case in x86_32 with optimize for size (-Os) where, for a few functions, gcc would align the stack frame and place a copy of the return address into it. The function graph tracer modified the copy and not the actual return address. On return from the funtion, it did not go to the tracer hook, but returned to the parent. This broke the function graph tracer, because the return of the parent (where gcc did not do this funky manipulation) returned to the location that the child function was suppose to. This caused strange kernel crashes. This test detected the problem and pointed out where the issue was. This modifies the parameters of one of the functions that the arch specific code calls, so it includes changes to arch code to accommodate the new prototype. Note, I notice that the parsic arch implements its own push_return_trace. This is now a generic function and the ftrace_push_return_trace should be used instead. This patch does not touch that code. Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Helge Deller <deller@gmx.de> Cc: Kyle McMartin <kyle@mcmartin.ca> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| | * function-graph: disable when both x86_32 and optimize for size are configuredSteven Rostedt2009-06-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | On x86_32, when optimize for size is set, gcc may align the frame pointer and make a copy of the the return address inside the stack frame. The return address that is located in the stack frame may not be the one used to return to the calling function. This will break the function graph tracer. The function graph tracer replaces the return address with a jump to a hook function that can trace the exit of the function. If it only replaces a copy, then the hook will not be called when the function returns. Worse yet, when the parent function returns, the function graph tracer will return back to the location of the child function which will easily crash the kernel with weird results. To see the problem, when i386 is compiled with -Os we get: c106be03: 57 push %edi c106be04: 8d 7c 24 08 lea 0x8(%esp),%edi c106be08: 83 e4 e0 and $0xffffffe0,%esp c106be0b: ff 77 fc pushl 0xfffffffc(%edi) c106be0e: 55 push %ebp c106be0f: 89 e5 mov %esp,%ebp c106be11: 57 push %edi c106be12: 56 push %esi c106be13: 53 push %ebx c106be14: 81 ec 8c 00 00 00 sub $0x8c,%esp c106be1a: e8 f5 57 fb ff call c1021614 <mcount> When it is compiled with -O2 instead we get: c10896f0: 55 push %ebp c10896f1: 89 e5 mov %esp,%ebp c10896f3: 83 ec 28 sub $0x28,%esp c10896f6: 89 5d f4 mov %ebx,0xfffffff4(%ebp) c10896f9: 89 75 f8 mov %esi,0xfffffff8(%ebp) c10896fc: 89 7d fc mov %edi,0xfffffffc(%ebp) c10896ff: e8 d0 08 fa ff call c1029fd4 <mcount> The compile with -Os will align the stack pointer then set up the frame pointer (%ebp), and it copies the return address back into the stack frame. The change to the return address in mcount is done to the copy and not the real place holder of the return address. Then compile with -O2 sets up the frame pointer first, this makes the change to the return address by mcount affect where the function will jump on exit. Reported-by: Jake Edge <jake@lwn.net> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * | Merge branch 'tip/tracing/urgent' of ↵Ingo Molnar2009-06-20
| |\| | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into tracing/urgent
| | * ring-buffer: have benchmark test print to trace bufferSteven Rostedt2009-06-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently the output of the ring buffer benchmark/test prints to the console. This test runs for ten seconds every ten seconds and ouputs the result after every iteration. This needlessly fills up the logs. This patch makes the ring buffer benchmark/test print to the ftrace buffer using trace_printk. To view the test results, you must examine the debug/tracing/trace file. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| | * ring-buffer: do not grab locks in nmiSteven Rostedt2009-06-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If ftrace_dump_on_oops is set, and an NMI detects a lockup, then it will need to read from the ring buffer. But the read side of the ring buffer still takes locks. This patch adds a check on the read side that if it is in an NMI, then it will disable the ring buffer and not take any locks. Reads can still happen on a disabled ring buffer. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| | * ring-buffer: add locks around rb_per_cpu_emptySteven Rostedt2009-06-17
| | | | | | | | | | | | | | | | | | | | | The checking of whether the buffer is empty or not needs to be serialized among the readers. Add the reader spin lock around it. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| | * ring-buffer: check for less than two in size allocationSteven Rostedt2009-06-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The ring buffer must have at least two pages allocated for the reader page swap to work. The page count check will miss the case of a zero size passed in. Even though a zero size ring buffer would probably fail an allocation, making the min size check for less than two instead of equal to one makes the code a bit more robust. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| | * ring-buffer: remove useless compile check for buffer_page sizeSteven Rostedt2009-06-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The original version of the ring buffer had a hack to map the page struct that held the pages of the buffer to also be the structure that the ring buffer would keep the pages in a link list. This overlap of the page struct was very dangerous and that hack was removed a while ago. But there was a check to make sure the buffer_page never became bigger than the page struct, and would fail the compile if it did. The check was only meaningful when we had the hack. Now that we have separate allocated descriptors for the buffer pages, we can remove this check. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| | * ring-buffer: remove useless warn on checkSteven Rostedt2009-06-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A check if "write > BUF_PAGE_SIZE" is done right after a if (write > BUF_PAGE_SIZE) return ...; Thus the check is actually testing the compiler and not the kernel. This is useless, remove it. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| | * ring-buffer: use BUF_PAGE_HDR_SIZE in calculating indexSteven Rostedt2009-06-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The index of the event is found by masking PAGE_MASK to it and subtracting the header size. Currently the header size is calculate by PAGE_SIZE - BUF_PAGE_SIZE, when we already have a macro BUF_PAGE_HDR_SIZE to define it. If we want to change BUF_PAGE_SIZE to something less than filling the rest of the page (this is done for debugging), then we break the algorithm to find the index. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * | tracing/urgent: warn in case of ftrace_start_up inbalanceFrederic Weisbecker2009-06-20
| | | | | | | | | | | | | | | | | | | | | | | | Prevent from further ftrace_start_up inbalances so that we avoid future nop patching omissions with dynamic ftrace. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org>
| * | tracing/urgent: fix unbalanced ftrace_start_upFrederic Weisbecker2009-06-20
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Perfcounter reports the following stats for a wide system profiling: # # (2364 samples) # # Overhead Symbol # ........ ...... # 15.40% [k] mwait_idle_with_hints 8.29% [k] read_hpet 5.75% [k] ftrace_caller 3.60% [k] ftrace_call [...] This snapshot has been taken while neither the function tracer nor the function graph tracer was running. With dynamic ftrace, such results show a wrong ftrace behaviour because all calls to ftrace_caller or ftrace_graph_caller (the patched calls to mcount) are supposed to be patched into nop if none of those tracers are running. The problem occurs after the first run of the function tracer. Once we launch it a second time, the callsites will never be nopped back, unless you set custom filters. For example it happens during the self tests at boot time. The function tracer selftest runs, and then the dynamic tracing is tested too. After that, the callsites are left un-nopped. This is because the reset callback of the function tracer tries to unregister two ftrace callbacks in once: the common function tracer and the function tracer with stack backtrace, regardless of which one is currently in use. It then creates an unbalance on ftrace_start_up value which is expected to be zero when the last ftrace callback is unregistered. When it reaches zero, the FTRACE_DISABLE_CALLS is set on the next ftrace command, triggering the patching into nop. But since it becomes unbalanced, ie becomes lower than zero, if the kernel functions are patched again (as in every further function tracer runs), they won't ever be nopped back. Note that ftrace_call and ftrace_graph_call are still patched back to ftrace_stub in the off case, but not the callers of ftrace_call and ftrace_graph_caller. It means that the tracing is well deactivated but we waste a useless call into every kernel function. This patch just unregisters the right ftrace_ops for the function tracer on its reset callback and ignores the other one which is not registered, fixing the unbalance. The problem also happens is .30 Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: stable@kernel.org
| * tracing/filters: fix race between filter setting and module unloadLi Zefan2009-06-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Module unload is protected by event_mutex, while setting filter is protected by filter_mutex. This leads to the race: echo 'bar == 0 || bar == 10' \ | > sample/filter | | insmod sample.ko add_pred("bar == 0") | -> n_preds == 1 | add_pred("bar == 100") | -> n_preds == 2 | | rmmod sample.ko | insmod sample.ko add_pred("&&") | -> n_preds == 1 (should be 3) | Now event->filter->preds is corrupted. An then when filter_match_preds() is called, the WARN_ON() in it will be triggered. To avoid the race, we remove filter_mutex, and replace it with event_mutex. [ Impact: prevent corruption of filters by module removing and loading ] Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> LKML-Reference: <4A375A4D.6000205@cn.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * tracing/filters: free filter_string in destroy_preds()Li Zefan2009-06-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | filter->filter_string is not freed when unloading a module: # insmod trace-events-sample.ko # echo "bar < 100" > /mnt/tracing/events/sample/foo_bar/filter # rmmod trace-events-sample.ko [ Impact: fix memory leak when unloading module ] Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> LKML-Reference: <4A375A30.9060802@cn.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * ring-buffer: use commit counters for commit pointer accountingSteven Rostedt2009-06-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The ring buffer is made up of three sets of pointers. The head page pointer, which points to the next page for the reader to get. The commit pointer and commit index, which points to the page and index of the last committed write respectively. The tail pointer and tail index, which points to the page and the index of the last reserved data respectively (non committed). The commit pointer is only moved forward by the outer most writer. If a nested writer comes in, it will not move the pointer forward. The current implementation has a flaw. It assumes that the outer most writer successfully reserved data. There's a small race window where the outer most writer could find the tail pointer, but a nested writer could come in (via interrupt) and move the tail forward, and even the commit forward. The outer writer would not realized the commit moved forward and the accounting will break. This patch changes the design to use counters in the per cpu buffers to keep track of commits. The counters are incremented at the start of the commit, and decremented at the end. If the end commit counter is 1, then it moves the commit pointers. A loop is made to check for races between checking and moving the commit pointers. Only the outer commit should move the pointers anyway. The test of knowing if a reserve is equal to the last commit update is still needed to know for time keeping. The time code is much less racey than the commit updates. This change not only solves the mentioned race, but also makes the code simpler. [ Impact: fix commit race and simplify code ] Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * ring-buffer: remove unused variableSteven Rostedt2009-06-16
| | | | | | | | | | | | | | | | | | Fix the compiler error: kernel/trace/ring_buffer.c: In function 'rb_move_tail': kernel/trace/ring_buffer.c:1236: warning: unused variable 'event' Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * ring-buffer: have benchmark test handle discarded eventsSteven Rostedt2009-06-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With the addition of commit: c7b0930857e2278f2e7714db6294e94c57f623b0 ring-buffer: prevent adding write in discarded area The ring buffer may now add discarded events when a write passes the end of a buffer page. Before, a discarded event was only added when the tracer deliberately created one. The ring buffer benchmark test does not handle discarded events when it reads the buffer and fails when it encounters one. Also fix the increment for large data entries (luckily, the test did not add any yet). [ Impact: fix false failure of ring buffer self test ] Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * ring-buffer: prevent adding write in discarded areaSteven Rostedt2009-06-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This a very tight race where an interrupt could come in and not have enough data to put into the end of a buffer page, and that it would fail to write and need to go to the next page. But if this happened when another writer was about to reserver their data, and that writer has smaller data to reserve, then it could succeed even though the interrupt moved the tail page. To pervent that, if we fail to store data, and by subtracting the amount we reserved we still have room for smaller data, we need to fill that space with "discarded" data. [ Impact: prevent race were buffer data may be lost ] Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * tracing/filters: strloc should be unsigned shortLi Zefan2009-06-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | I forgot to update filter code accordingly in "tracing/events: change the type of __str_loc_item to unsigned short" (commt b0aae68cc5508f3c2fbf728988c954db4c8b8a53) It can cause system crash: # echo 1 > tracing/events/irq/irq_handler_entry/enable # echo 'name == eth0' > tracing/events/irq/irq_handler_entry/filter [ Impact: fix crash while filtering on __string() field ] Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> LKML-Reference: <4A35B905.3090500@cn.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * tracing/filters: operand can be negativeLi Zefan2009-06-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This should be a bug: # cat format name: foo_bar ID: 71 format: ... field:int bar; offset:24; size:4; # echo 'bar < 0' > filter # echo 'bar < -1' > filter bash: echo: write error: Invalid argument [ Impact: fix to allow negative operand in filer expr ] Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> LKML-Reference: <4A35B8DF.60400@cn.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * tracing: replace a GFP_ATOMIC with GFP_KERNEL allocationLi Zefan2009-06-15
| | | | | | | | | | | | | | | | | | | | | | Atomic allocation is not needed here. [ Impact: clean up of memory alloction type ] Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> LKML-Reference: <4A35B898.2050607@cn.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * tracing: fix a typo in tracing_cpumask_write()Li Zefan2009-06-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It's tracing_cpumask_new that should be kfree()ed. This causes tracing_cpumask to be freed due to the typo: # echo z > tracing_cpumask bash: echo: write error: Invalid argument And subsequent reads/writes to tracing_cpuamsk will access this already-freed tracing_cpumask, thus may lead to crash. [ Impact: fix leak and crash when writing invalid val to tracing_cpumask ] Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> LKML-Reference: <4A35B86A.7070608@cn.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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