lockdep: Fix preemption WARN for spurious IRQ-enable
authorPeter Zijlstra <peterz@infradead.org>
Thu, 22 Oct 2020 10:23:02 +0000 (12:23 +0200)
committerPeter Zijlstra <peterz@infradead.org>
Thu, 22 Oct 2020 10:37:22 +0000 (12:37 +0200)
commitf8e48a3dca060e80f672d398d181db1298fbc86c
tree8ccab9b05381c1cd06d368bedf620bcd8bb3ae7b
parented3e453798d4f81c99056aa09fcd79d0874a60fd
lockdep: Fix preemption WARN for spurious IRQ-enable

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>
kernel/locking/lockdep.c