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>

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 3e99dfe..fc206ae 100644 (file)
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -4057,7 +4057,7 @@ 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())) {
@@ -4126,7 +4126,7 @@ 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()) {