6.5-stable review patch. If anyone has any objections, please let me know.
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From: Lukas Wunner lukas@wunner.de
[ Upstream commit cccd32816506cbac3a4c65d9dff51b3125ef1a03 ]
Commit:
5a5d7e9badd2 ("cpuidle: lib/bug: Disable rcu_is_watching() during WARN/BUG")
amended warn_slowpath_fmt() to disable preemption until the WARN splat has been emitted.
However the commit neglected to reenable preemption in the !fmt codepath, i.e. when a WARN splat is emitted without additional format string.
One consequence is that users may see more splats than intended. E.g. a WARN splat emitted in a work item results in at least two extra splats:
BUG: workqueue leaked lock or atomic (emitted by process_one_work())
BUG: scheduling while atomic (emitted by worker_thread() -> schedule())
Ironically the point of the commit was to *avoid* extra splats. ;)
Fix it.
Fixes: 5a5d7e9badd2 ("cpuidle: lib/bug: Disable rcu_is_watching() during WARN/BUG") Signed-off-by: Lukas Wunner lukas@wunner.de Signed-off-by: Ingo Molnar mingo@kernel.org Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Thomas Gleixner tglx@linutronix.de Cc: Paul E. McKenney paulmck@kernel.org Link: https://lore.kernel.org/r/3ec48fde01e4ee6505f77908ba351bad200ae3d1.169476368... Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/panic.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/kernel/panic.c b/kernel/panic.c index 10effe40a3fa6..ea1c5fcb2d191 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -697,6 +697,7 @@ void warn_slowpath_fmt(const char *file, int line, unsigned taint, if (!fmt) { __warn(file, line, __builtin_return_address(0), taint, NULL, NULL); + warn_rcu_exit(rcu); return; }