linux/kernel/trace, branch v2.6.30.1

tracing/urgent: fix unbalanced ftrace_start_up

2009-07-02T23:50:22Z

commit c85a17e22695969aa24a7ffa40cf26d6e6fcfd50 upstream. 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 Cc: Steven Rostedt Signed-off-by: Greg Kroah-Hartman

tracing: Append prompt in /debug/tracing/README file

2009-05-15T17:43:22Z

append prompt in /debug/tracing/README file. This is trivial issue. Fix typo Mini Howto file(README) for ftrace. [ Impact: cleanup ] Signed-off-by: GeunSik Lim Acked-by: Steven Rostedt Cc: williams LKML-Reference: <1242289418.31161.45.camel@centos51> Signed-off-by: Ingo Molnar

tracing: fix ref count in splice pages

2009-04-29T06:02:44Z

The pages allocated for the splice binary buffer did not initialize the ref count correctly. This caused pages not to be freed and causes a drastic memory leak. Thanks to logdev I was able to trace the tracer to find where the leak was. [ Impact: stop memory leak when using splice ] Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar

tracing: Fix branch tracer header

2009-04-14T00:30:36Z

Before patch: # tracer: branch # # TASK-PID CPU# TIMESTAMP FUNCTION # | | | | | <...>-2981 [000] 24008.872738: [ ok ] trace_irq_handler_exit:irq_event_types.h:41 <...>-2981 [000] 24008.872742: [ ok ] note_interrupt:spurious.c:229 ... After patch: # tracer: branch # # TASK-PID CPU# TIMESTAMP CORRECT FUNC:FILE:LINE # | | | | | | <...>-2985 [000] 26329.142970: [ ok ] slab_free:slub.c:1776 <...>-2985 [000] 26329.142972: [ ok ] trace_kmem_cache_free:kmem_event_types.h:191 ... Signed-off-by: Zhao Lei Acked-by: Frederic Weisbecker Cc: Steven Rostedt Cc: Tom Zanussi LKML-Reference: <49E2F19A.3040006@cn.fujitsu.com> Signed-off-by: Ingo Molnar

tracing: Fix power tracer header

2009-04-13T21:39:57Z

Before patch: # tracer: power # # TASK-PID CPU# TIMESTAMP FUNCTION # | | | | | [ 676.875865889] CSTATE: Going to C1 on cpu 0 for 0.005911463 [ 676.882938805] CSTATE: Going to C1 on cpu 0 for 0.104796532 ... After patch: # tracer: power # # TIMESTAMP STATE EVENT # | | | [ 676.875865889] CSTATE: Going to C1 on cpu 0 for 0.005911463 [ 676.882938805] CSTATE: Going to C1 on cpu 0 for 0.104796532 ... v2: Use seq_puts instead of seq_printf Signed-off-by: Zhao Lei Cc: Arjan van de Ven Cc: Steven Rostedt Cc: Frederic Weisbecker Cc: Tom Zanussi LKML-Reference: <49E2E889.5000903@cn.fujitsu.com> Signed-off-by: Ingo Molnar

tracing/filters: return proper error code when writing filter file

2009-04-12T09:59:29Z

- propagate return value of filter_add_pred() to the user - return -ENOSPC but not -ENOMEM or -EINVAL when the filter array is full Signed-off-by: Li Zefan Acked-by: Tom Zanussi Acked-by: Frederic Weisbecker Cc: Steven Rostedt LKML-Reference: <49E04CF0.3010105@cn.fujitsu.com> Signed-off-by: Ingo Molnar

tracing/filters: allow user input integer to be oct or hex

2009-04-12T09:59:28Z

Before patch: # echo 'parent_pid == 0x10' > events/sched/sched_process_fork/filter # cat sched/sched_process_fork/filter parent_pid == 0 After patch: # cat sched/sched_process_fork/filter parent_pid == 16 Also check the input more strictly. Signed-off-by: Li Zefan Acked-by: Tom Zanussi Acked-by: Frederic Weisbecker Cc: Steven Rostedt LKML-Reference: <49E04C53.4010600@cn.fujitsu.com> Signed-off-by: Ingo Molnar

tracing/filters: fix NULL pointer dereference

2009-04-12T09:59:28Z

Try this, and you'll see NULL pointer dereference bug: # echo -n 'parent_comm ==' > sched/sched_process_fork/filter Because we passed NULL ptr to simple_strtoull(). Signed-off-by: Li Zefan Acked-by: Tom Zanussi Acked-by: Frederic Weisbecker Cc: Steven Rostedt LKML-Reference: <49E04C43.1050504@cn.fujitsu.com> Signed-off-by: Ingo Molnar

tracing/filters: NIL-terminate user input filter

2009-04-12T09:59:27Z

Make sure messages from user space are NIL-terminated strings, otherwise we could dump random memory while reading filter file. Try this: # echo 'parent_comm ==' > events/sched/sched_process_fork/filter # cat events/sched/sched_process_fork/filter parent_comm == � Signed-off-by: Li Zefan Acked-by: Tom Zanussi Acked-by: Frederic Weisbecker Cc: Steven Rostedt LKML-Reference: <49E04C32.6060508@cn.fujitsu.com> Signed-off-by: Ingo Molnar

ftrace: Output REC->var instead of __entry->var for trace format

2009-04-10T13:48:53Z

print fmt: "irq=%d return=%s", __entry->irq, __entry->ret ? \"handled\" : \"unhandled\" "__entry" should be convert to "REC" by __stringify() macro. Signed-off-by: Zhao Lei Acked-by: Frederic Weisbecker Cc: Steven Rostedt LKML-Reference: <49DC679D.2090901@cn.fujitsu.com> Signed-off-by: Ingo Molnar