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/target.h | 98 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 98 insertions(+) create mode 100644 tools/perf/util/target.h (limited to 'tools/perf/util/target.h') diff --git a/tools/perf/util/target.h b/tools/perf/util/target.h new file mode 100644 index 000000000..bc2bff9c6 --- /dev/null +++ b/tools/perf/util/target.h @@ -0,0 +1,98 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _PERF_TARGET_H +#define _PERF_TARGET_H + +#include +#include + +struct target { + const char *pid; + const char *tid; + const char *cpu_list; + const char *bpf_str; + bool system_wide; + bool uses_mmap; + bool default_per_cpu; + bool per_thread; + bool use_bpf; + bool inherit; + int initial_delay; + const char *attr_map; +}; + +enum target_errno { + TARGET_ERRNO__SUCCESS = 0, + + /* + * Choose an arbitrary negative big number not to clash with standard + * errno since SUS requires the errno has distinct positive values. + * See 'Issue 6' in the link below. + * + * http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/errno.h.html + */ + __TARGET_ERRNO__START = -10000, + + /* for target__validate() */ + TARGET_ERRNO__PID_OVERRIDE_CPU = __TARGET_ERRNO__START, + TARGET_ERRNO__PID_OVERRIDE_SYSTEM, + TARGET_ERRNO__SYSTEM_OVERRIDE_THREAD, + TARGET_ERRNO__BPF_OVERRIDE_CPU, + TARGET_ERRNO__BPF_OVERRIDE_PID, + TARGET_ERRNO__BPF_OVERRIDE_THREAD, + + __TARGET_ERRNO__END, +}; + +enum target_errno target__validate(struct target *target); + +uid_t parse_uid(const char *str); + +int target__strerror(struct target *target, int errnum, char *buf, size_t buflen); + +static inline bool target__has_task(const struct target *target) +{ + return target->tid || target->pid; +} + +static inline bool target__has_cpu(const struct target *target) +{ + return target->system_wide || target->cpu_list; +} + +static inline bool target__none(const struct target *target) +{ + return !target__has_task(target) && !target__has_cpu(target); +} + +static inline bool target__enable_on_exec(const struct target *target) +{ + /* + * Normally enable_on_exec should be set if: + * 1) The tracee process is forked (not attaching to existed task or cpu). + * 2) And initial_delay is not configured. + * Otherwise, we enable tracee events manually. + */ + return target__none(target) && !target->initial_delay; +} + +static inline bool target__has_per_thread(const struct target *target) +{ + return target->system_wide && target->per_thread; +} + +static inline bool target__uses_dummy_map(const struct target *target) +{ + bool use_dummy = false; + + if (target->default_per_cpu) + use_dummy = target->per_thread ? true : false; + else if (target__has_task(target) || + (!target__has_cpu(target) && !target->uses_mmap)) + use_dummy = true; + else if (target__has_per_thread(target)) + use_dummy = true; + + return use_dummy; +} + +#endif /* _PERF_TARGET_H */ -- cgit v1.3.1