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 --- include/trace/events/lock.h | 166 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 166 insertions(+) create mode 100644 include/trace/events/lock.h (limited to 'include/trace/events/lock.h') diff --git a/include/trace/events/lock.h b/include/trace/events/lock.h new file mode 100644 index 000000000..b1d5b18c4 --- /dev/null +++ b/include/trace/events/lock.h @@ -0,0 +1,166 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#undef TRACE_SYSTEM +#define TRACE_SYSTEM lock + +#if !defined(_TRACE_LOCK_H) || defined(TRACE_HEADER_MULTI_READ) +#define _TRACE_LOCK_H + +#include + +/* flags for lock:contention_begin */ +#define LCB_F_SPIN (1U << 0) +#define LCB_F_READ (1U << 1) +#define LCB_F_WRITE (1U << 2) +#define LCB_F_RT (1U << 3) +#define LCB_F_PERCPU (1U << 4) +#define LCB_F_MUTEX (1U << 5) + + +#ifdef CONFIG_LOCKDEP + +#include + +TRACE_EVENT(lock_acquire, + + TP_PROTO(struct lockdep_map *lock, unsigned int subclass, + int trylock, int read, int check, + struct lockdep_map *next_lock, unsigned long ip), + + TP_ARGS(lock, subclass, trylock, read, check, next_lock, ip), + + TP_STRUCT__entry( + __field(unsigned int, flags) + __string(name, lock->name) + __field(void *, lockdep_addr) + ), + + TP_fast_assign( + __entry->flags = (trylock ? 1 : 0) | (read ? 2 : 0); + __assign_str(name); + __entry->lockdep_addr = lock; + ), + + TP_printk("%p %s%s%s", __entry->lockdep_addr, + (__entry->flags & 1) ? "try " : "", + (__entry->flags & 2) ? "read " : "", + __get_str(name)) +); + +DECLARE_EVENT_CLASS(lock, + + TP_PROTO(struct lockdep_map *lock, unsigned long ip), + + TP_ARGS(lock, ip), + + TP_STRUCT__entry( + __string( name, lock->name ) + __field( void *, lockdep_addr ) + ), + + TP_fast_assign( + __assign_str(name); + __entry->lockdep_addr = lock; + ), + + TP_printk("%p %s", __entry->lockdep_addr, __get_str(name)) +); + +DEFINE_EVENT(lock, lock_release, + + TP_PROTO(struct lockdep_map *lock, unsigned long ip), + + TP_ARGS(lock, ip) +); + +#ifdef CONFIG_LOCK_STAT + +DEFINE_EVENT(lock, lock_contended, + + TP_PROTO(struct lockdep_map *lock, unsigned long ip), + + TP_ARGS(lock, ip) +); + +DEFINE_EVENT(lock, lock_acquired, + + TP_PROTO(struct lockdep_map *lock, unsigned long ip), + + TP_ARGS(lock, ip) +); + +#endif /* CONFIG_LOCK_STAT */ +#endif /* CONFIG_LOCKDEP */ + +TRACE_EVENT(contention_begin, + + TP_PROTO(void *lock, unsigned int flags), + + TP_ARGS(lock, flags), + + TP_STRUCT__entry( + __field(void *, lock_addr) + __field(unsigned int, flags) + ), + + TP_fast_assign( + __entry->lock_addr = lock; + __entry->flags = flags; + ), + + TP_printk("%p (flags=%s)", __entry->lock_addr, + __print_flags(__entry->flags, "|", + { LCB_F_SPIN, "SPIN" }, + { LCB_F_READ, "READ" }, + { LCB_F_WRITE, "WRITE" }, + { LCB_F_RT, "RT" }, + { LCB_F_PERCPU, "PERCPU" }, + { LCB_F_MUTEX, "MUTEX" } + )) +); + +TRACE_EVENT(contention_end, + + TP_PROTO(void *lock, int ret), + + TP_ARGS(lock, ret), + + TP_STRUCT__entry( + __field(void *, lock_addr) + __field(int, ret) + ), + + TP_fast_assign( + __entry->lock_addr = lock; + __entry->ret = ret; + ), + + TP_printk("%p (ret=%d)", __entry->lock_addr, __entry->ret) +); + +/* kernel/locking/mutex.c */ +int arch_contended_release_trace_reg(void); +void arch_contended_release_trace_unreg(void); + +TRACE_EVENT_FN(contended_release, + + TP_PROTO(void *lock), + + TP_ARGS(lock), + + TP_STRUCT__entry( + __field(void *, lock_addr) + ), + + TP_fast_assign( + __entry->lock_addr = lock; + ), + + TP_printk("%p", __entry->lock_addr), + + arch_contended_release_trace_reg, arch_contended_release_trace_unreg +); + +#endif /* _TRACE_LOCK_H */ + +/* This part must be outside protection */ +#include -- cgit v1.3.1