On Wed, 22 Jan 2025 17:29:36 -0500 Steven Rostedt <rost...@goodmis.org> wrote:
> On Wed, 22 Jan 2025 08:59:39 +0100 > Nam Cao <nam...@linutronix.de> wrote: > > > Hi, > > > > I installed a kretprobe on the function "rt_mutex_slowunlock". Although the > > function is called, the probe is never hit. > > > > How did you install the kretprobe? > If you specify one original 'symbol' name to tracefs/kprobe_events, it only sets the kretprobe event on that symbol. > > The reason is because there are 3 copies of rt_mutex_slowunlock() in > > vmlinux (at least for x86 defconfig + CONFIG_PREEMPT_RT). But probe point > > is only installed in 1 copy. You can add those copies manually on the same event but,... > > > > Is this considered a bug? Or is kprobe not intended to be used for local > > function? Should we modify kprobe to support such cases? > > It's not a bug, but just the way the compiler works. > > Have you tried "perf probe" to install the probes? That uses dwarf info to > find all the functions. Yes, I recommend you to use `perf probe` (under tools/perf) to put kretprobes on those copies. See tools/perf/Documentation/perf-probe.txt for details. Thank you, > > -- Steve -- Masami Hiramatsu (Google) <mhira...@kernel.org>
