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/libdw.h | 58 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 58 insertions(+) create mode 100644 tools/perf/util/libdw.h (limited to 'tools/perf/util/libdw.h') diff --git a/tools/perf/util/libdw.h b/tools/perf/util/libdw.h new file mode 100644 index 000000000..b12094737 --- /dev/null +++ b/tools/perf/util/libdw.h @@ -0,0 +1,58 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef PERF_LIBDW_H +#define PERF_LIBDW_H + +#include + +struct dso; +struct inline_node; +struct symbol; + +#ifdef HAVE_LIBDW_SUPPORT +/* + * libdw__addr2line - Convert address to source location using libdw + * @addr: Address to resolve + * @file: Pointer to return filename (caller must free) + * @line_nr: Pointer to return line number + * @dso: The dso struct + * @unwind_inlines: Whether to unwind inline function calls + * @node: Inline node list to append to + * @sym: The symbol associated with the address + * + * This function initializes a Dwfl context for the DSO if not already present, + * finds the source line information for the given address, and optionally + * resolves inline function call chains. + * + * Returns 1 on success (found), 0 on failure (not found). + */ +int libdw__addr2line(u64 addr, char **file, + unsigned int *line_nr, struct dso *dso, + bool unwind_inlines, struct inline_node *node, + struct symbol *sym); + +/* + * dso__free_libdw - Free libdw resources associated with the DSO + * @dso: The dso to free resources for + * + * This function cleans up the Dwfl context used for addr2line lookups. + */ +void dso__free_libdw(struct dso *dso); + +#else /* HAVE_LIBDW_SUPPORT */ + +static inline int libdw__addr2line(u64 addr __maybe_unused, char **file __maybe_unused, + unsigned int *line_nr __maybe_unused, + struct dso *dso __maybe_unused, + bool unwind_inlines __maybe_unused, + struct inline_node *node __maybe_unused, + struct symbol *sym __maybe_unused) +{ + return 0; +} + +static inline void dso__free_libdw(struct dso *dso __maybe_unused) +{ +} +#endif /* HAVE_LIBDW_SUPPORT */ + +#endif /* PERF_LIBDW_H */ -- cgit v1.3.1