Messages in this thread Patch in this message | | | From | "Masami Hiramatsu (Google)" <> | Subject | [PATCH] fprobes: Add a comment why fprobe_kprobe_handler exits if kprobe is running | Date | Sat, 8 Jul 2023 01:38:03 +0900 |
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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> --- 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;
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