On Wed, Feb 28, 2024 at 01:31:12PM -0500, Steven Rostedt wrote:
> From: "Steven Rostedt (Google)" <rost...@goodmis.org>
>
> 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.
>
> Reported-by: Borislav Petkov <b...@alien8.de>
> Signed-off-by: Steven Rostedt (Google) <rost...@goodmis.org>
> ---
> include/linux/tracepoint.h | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
Tested-by: Borislav Petkov (AMD) <b...@alien8.de>
meaning: tested that it really fires:
[ 1.196008] Running RCU Tasks wait API self tests
[ 1.200227] ------------[ cut here ]------------
[ 1.203899] RCU not watching for tracepoint
[ 1.203899] WARNING: CPU: 0 PID: 0 at include/trace/events/lock.h:24
lock_acquire+0x2d3/0x300
...
Thx.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
