diff options
| author | Steven Rostedt (Google) <rostedt@goodmis.org> | 2024-02-28 13:31:12 -0500 |
|---|---|---|
| committer | Steven Rostedt (Google) <rostedt@goodmis.org> | 2024-03-18 10:33:06 -0400 |
| commit | 1b273124107cc8b9dd52228eba701efa516a3d92 (patch) | |
| tree | 467081446c4222b0ecdfb4b4402abc0504653987 | |
| parent | d6cb38e10810743addf8cac0b277861d614de1e9 (diff) | |
tracepoints: Use WARN() and not WARN_ON() for warnings
There are two WARN_ON*() warnings in tracepoint.h that deal with RCU
usage. But when they trigger, especially from using a TRACE_EVENT()
macro, the information is not very helpful and is confusing:
------------[ cut here ]------------
WARNING: CPU: 0 PID: 0 at include/trace/events/lock.h:24 lock_acquire+0x2b2/0x2d0
Where the above warning takes you to:
TRACE_EVENT(lock_acquire, <<<--- line 24 in lock.h
TP_PROTO(struct lockdep_map *lock, unsigned int subclass,
int trylock, int read, int check,
struct lockdep_map *next_lock, unsigned long ip),
[..]
Change the WARN_ON_ONCE() to WARN_ONCE() and add a string that allows
someone to search for exactly where the bug happened.
Link: https://lore.kernel.org/linux-trace-kernel/20240228133112.0d64fb1b@gandalf.local.home
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Reported-by: Borislav Petkov <bp@alien8.de>
Tested-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
| -rw-r--r-- | include/linux/tracepoint.h | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h index 88c0ba623ee6..689b6d71590e 100644 --- a/include/linux/tracepoint.h +++ b/include/linux/tracepoint.h @@ -199,7 +199,8 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) if (!(cond)) \ return; \ \ - if (WARN_ON_ONCE(RCUIDLE_COND(rcuidle))) \ + if (WARN_ONCE(RCUIDLE_COND(rcuidle), \ + "Bad RCU usage for tracepoint")) \ return; \ \ /* keep srcu and sched-rcu usage consistent */ \ @@ -259,7 +260,8 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) TP_ARGS(args), \ TP_CONDITION(cond), 0); \ if (IS_ENABLED(CONFIG_LOCKDEP) && (cond)) { \ - WARN_ON_ONCE(!rcu_is_watching()); \ + WARN_ONCE(!rcu_is_watching(), \ + "RCU not watching for tracepoint"); \ } \ } \ __DECLARE_TRACE_RCU(name, PARAMS(proto), PARAMS(args), \ |