This is a note to let you know that I've just added the patch titled
lockdep: Fix preemption WARN for spurious IRQ-enable
to the 5.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
lockdep-fix-preemption-warn-for-spurious-irq-enable.patch
and it can be found in the queue-5.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 3caf638ca9f4c8e5ca1dfb7f96090c5adb42a82e
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Date: Thu Oct 22 12:23:02 2020 +0200
lockdep: Fix preemption WARN for spurious IRQ-enable
[ Upstream commit f8e48a3dca060e80f672d398d181db1298fbc86c ]
It is valid (albeit uncommon) to call local_irq_enable() without first
having called local_irq_disable(). In this case we enter
lockdep_hardirqs_on*() with IRQs enabled and trip a preemption warning
for using __this_cpu_read().
Use this_cpu_read() instead to avoid the warning.
Fixes: 4d004099a6 ("lockdep: Fix lockdep recursion")
Reported-by: syzbot+53f8ce8bbc07924b6417@xxxxxxxxxxxxxxxxxxxxxxxxx
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 85d15f0362dc5..3eb35ad1b5241 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -3681,7 +3681,7 @@ void lockdep_hardirqs_on_prepare(unsigned long ip)
if (unlikely(in_nmi()))
return;
- if (unlikely(__this_cpu_read(lockdep_recursion)))
+ if (unlikely(this_cpu_read(lockdep_recursion)))
return;
if (unlikely(lockdep_hardirqs_enabled())) {
@@ -3750,7 +3750,7 @@ void noinstr lockdep_hardirqs_on(unsigned long ip)
goto skip_checks;
}
- if (unlikely(__this_cpu_read(lockdep_recursion)))
+ if (unlikely(this_cpu_read(lockdep_recursion)))
return;
if (lockdep_hardirqs_enabled()) {
