Commit d5f28bb1 authored Jul 08, 2023 by Masami Hiramatsu (Google)

fprobes: Add a comment why fprobe_kprobe_handler exits if kprobe is running

Add a comment the reason why fprobe_kprobe_handler() exits if any other
kprobe is running.

Link: https://lore.kernel.org/all/168874788299.159442.2485957441413653858.stgit@devnote2/



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>

parent 195b9cb5

kernel/trace/fprobe.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -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++;
		goto recursion_unlock;