From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops There's some internal state that ftrace_ops needs to have set, but since it can be declared outside of the ftrace.c code, it calls ftrace_ops_init() on the ops in every global function. The issue is that if two tasks call it on the same ops at the same time it is possible to have the initialization of one corrupt the initialization of the other call. Create a ops_mutex to use to synchronize every initialization of the ftrace_ops. The mutex is taken within checking the ftrace_ops flag that states it was initializied but the flag is checked again after the mutex has been taken. Checking first outside the mutex allows it to shortcut having to take the mutex. But then the check needs to be done again after the mute is taken in case of races. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock") Reported-by: sashiko-bot@kernel.org Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/ Signed-off-by: Steven Rostedt --- tools/perf/util/pfm.h | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) create mode 100644 tools/perf/util/pfm.h (limited to 'tools/perf/util/pfm.h') diff --git a/tools/perf/util/pfm.h b/tools/perf/util/pfm.h new file mode 100644 index 000000000..fb25c2749 --- /dev/null +++ b/tools/perf/util/pfm.h @@ -0,0 +1,38 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Support for libpfm4 event encoding. + * + * Copyright 2020 Google LLC. + */ +#ifndef __PERF_PFM_H +#define __PERF_PFM_H + +#include "print-events.h" +#include + +#ifdef HAVE_LIBPFM +int parse_libpfm_events_option(const struct option *opt, const char *str, + int unset); + +void print_libpfm_events(const struct print_callbacks *print_cb, void *print_state); + +#else +#include + +static inline int parse_libpfm_events_option( + const struct option *opt __maybe_unused, + const char *str __maybe_unused, + int unset __maybe_unused) +{ + return 0; +} + +static inline void print_libpfm_events(const struct print_callbacks *print_cb __maybe_unused, + void *print_state __maybe_unused) +{ +} + +#endif + + +#endif /* __PERF_PFM_H */ -- cgit v1.3.1