| From 3caf638ca9f4c8e5ca1dfb7f96090c5adb42a82e Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Thu, 22 Oct 2020 12:23:02 +0200 |
| Subject: lockdep: Fix preemption WARN for spurious IRQ-enable |
| |
| From: Peter Zijlstra <peterz@infradead.org> |
| |
| [ 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@syzkaller.appspotmail.com |
| Reported-by: kernel test robot <lkp@intel.com> |
| Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| kernel/locking/lockdep.c | 4 ++-- |
| 1 file changed, 2 insertions(+), 2 deletions(-) |
| |
| 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()) { |
| -- |
| 2.27.0 |
| |
