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| author | Masami Hiramatsu (Google) <mhiramat@kernel.org> | 2026-07-02 21:12:41 +0900 |
|---|---|---|
| committer | Masami Hiramatsu (Google) <mhiramat@kernel.org> | 2026-07-14 22:43:16 +0900 |
| commit | f2183452402508ad68ea01eed18ae8eecfcd8f0a (patch) | |
| tree | a7ae00c583a20ab6f56fb9e270f659d7211a9d3a /kernel/trace/trace.c | |
| parent | 52c76ec18ebacdcf7e227c06f4215bc49e5d284c (diff) | |
tracing/probes: Support field specifier option for typecast
Add a field specifier option for the typecast. This works like
container_of() macro.
(STRUCT[,FIELD[.FIELD2...]])VAR
This is equivalent to :
container_of(VAR, struct STRUCT, FIELD[.FIELD2...])
For example:
echo "f tick_nohz_handler next_tick=(tick_sched,sched_timer)timer->next_tick" >> dynamic_events
This will trace tick_nohz_handler() with its tick_sched::next_tick which
is converted from @timer by contianer_of(tick, struct tick_sched, sched_timer).
So, if you enabkle both fprobes:tick_nohz_handler__entry and
timer:hrtimer_expire_entry events, we will see something like:
<idle>-0 [002] d.h1. 3778.087272: hrtimer_expire_entry: hrtimer=00000000d63db328 f
unction=tick_nohz_handler now=3777450051040
<idle>-0 [002] d.h1. 3778.087281: tick_nohz_handler__entry: (tick_nohz_handler+0x4
/0x140) next_tick=3777450000000
Link: https://lore.kernel.org/all/178271365745.1176915.725923927180862257.stgit@devnote2/
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Diffstat (limited to 'kernel/trace/trace.c')
| -rw-r--r-- | kernel/trace/trace.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index e56ee034c486..5670c4b91dc0 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -4322,8 +4322,8 @@ static const char readme_msg[] = #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API "\t $stack<index>, $stack, $retval, $comm, $arg<N>,\n" #ifdef CONFIG_PROBE_EVENTS_BTF_ARGS - "\t [(structname)]<argname>[->field[->field|.field...]],\n" - "\t [(structname)](fetcharg)->field[->field|.field...],\n" + "\t [(structname[,field])]<argname>[->field[->field|.field...]],\n" + "\t [(structname[,field])](fetcharg)->field[->field|.field...],\n" #endif #else "\t $stack<index>, $stack, $retval, $comm,\n" |