| Message ID | 168874788299.159442.2485957441413653858.stgit@devnote2 (mailing list archive) |
|---|---|
| State | Accepted |
| Delegated to: | Masami Hiramatsu |
| Headers | show |
| Series | fprobes: Add a comment why fprobe_kprobe_handler exits if kprobe is running | expand |
On Sat, 8 Jul 2023 01:38:03 +0900 "Masami Hiramatsu (Google)" <mhiramat@kernel.org> wrote: > From: Masami Hiramatsu (Google) <mhiramat@kernel.org> > > Add a comment the reason why fprobe_kprobe_handler() exits if any other > kprobe is running. > > Suggested-by: Steven Rostedt <rostedt@goodmis.org> > Link: https://lore.kernel.org/all/20230706120916.3c6abf15@gandalf.local.home/ > Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org> -- Steve > --- > kernel/trace/fprobe.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c > index 75517667b54f..133b31f44945 100644 > --- a/kernel/trace/fprobe.c > +++ b/kernel/trace/fprobe.c > @@ -100,6 +100,12 @@ static void fprobe_kprobe_handler(unsigned long ip, unsigned long parent_ip, > return; > } > > + /* > + * This user handler is shared with other kprobes and is not expected to be > + * called recursively. So if any other kprobe handler is running, this will > + * exit as kprobe does. See the section 'Share the callbacks with kprobes' > + * in Documentation/trace/fprobe.rst for more information. > + */ > if (unlikely(kprobe_running())) { > fp->nmissed++; > return;
diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c index 75517667b54f..133b31f44945 100644 --- a/kernel/trace/fprobe.c +++ b/kernel/trace/fprobe.c @@ -100,6 +100,12 @@ static void fprobe_kprobe_handler(unsigned long ip, unsigned long parent_ip, return; } + /* + * This user handler is shared with other kprobes and is not expected to be + * called recursively. So if any other kprobe handler is running, this will + * exit as kprobe does. See the section 'Share the callbacks with kprobes' + * in Documentation/trace/fprobe.rst for more information. + */ if (unlikely(kprobe_running())) { fp->nmissed++; return;