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| author |   Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> | 2011-06-08 16:09:34 +0900 |
|---|---|---|
| committer |   Steven Rostedt <rostedt@goodmis.org> | 2011-06-14 22:48:53 -0400 |
| commit | 1fd8df2c3970c9e7e4e262354154ee39e58bdd7c (patch) | |
| tree | 640fbc584af8870917ea6d1fab4da49d299038ad /include/linux/ftrace_event.h | |
| parent | stack_trace: Add weak save_stack_trace_regs() (diff) | |
| download | linux-dev-1fd8df2c3970c9e7e4e262354154ee39e58bdd7c.tar.xz linux-dev-1fd8df2c3970c9e7e4e262354154ee39e58bdd7c.zip | |
tracing/kprobes: Fix kprobe-tracer to support stack trace
Fix to support kernel stack trace correctly on kprobe-tracer.
Since the execution path of kprobe-based dynamic events is different
from other tracepoint-based events, normal ftrace_trace_stack() doesn't
work correctly. To fix that, this introduces ftrace_trace_stack_regs()
which traces stack via pt_regs instead of current stack register.
e.g.
# echo p schedule+4 > /sys/kernel/debug/tracing/kprobe_events
# echo 1 > /sys/kernel/debug/tracing/options/stacktrace
# echo 1 > /sys/kernel/debug/tracing/events/kprobes/enable
# head -n 20 /sys/kernel/debug/tracing/trace
bash-2968 [000] 10297.050245: p_schedule_4: (schedule+0x4/0x4ca)
bash-2968 [000] 10297.050247: <stack trace>
=> schedule_timeout
=> n_tty_read
=> tty_read
=> vfs_read
=> sys_read
=> system_call_fastpath
kworker/0:1-2940 [000] 10297.050265: p_schedule_4: (schedule+0x4/0x4ca)
kworker/0:1-2940 [000] 10297.050266: <stack trace>
=> worker_thread
=> kthread
=> kernel_thread_helper
sshd-1132 [000] 10297.050365: p_schedule_4: (schedule+0x4/0x4ca)
sshd-1132 [000] 10297.050365: <stack trace>
=> sysret_careful
Note: Even with this fix, the first entry will be skipped
if the probe is put on the function entry area before
the frame pointer is set up (usually, that is 4 bytes
(push %bp; mov %sp %bp) on x86), because stack unwinder
depends on the frame pointer.
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: yrl.pp-manager.tt@hitachi.com
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Namhyung Kim <namhyung@gmail.com>
Link: http://lkml.kernel.org/r/20110608070934.17777.17116.stgit@fedora15
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'include/linux/ftrace_event.h')
| -rw-r--r-- | include/linux/ftrace_event.h | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h index 59d3ef100eb9..b1e69eefc203 100644 --- a/include/linux/ftrace_event.h +++ b/include/linux/ftrace_event.h @@ -129,6 +129,10 @@ void trace_current_buffer_unlock_commit(struct ring_buffer *buffer, void trace_nowake_buffer_unlock_commit(struct ring_buffer *buffer, struct ring_buffer_event *event, unsigned long flags, int pc); +void trace_nowake_buffer_unlock_commit_regs(struct ring_buffer *buffer, + struct ring_buffer_event *event, + unsigned long flags, int pc, + struct pt_regs *regs); void trace_current_buffer_discard_commit(struct ring_buffer *buffer, struct ring_buffer_event *event); |