Commit-ID: 8795d7717c467bea7b0a0649d44a258e09f34db2
Gitweb: http://git.kernel.org/tip/8795d7717c467bea7b0a0649d44a258e09f34db2
Author: Frederic Weisbecker <fweisbec@xxxxxxxxx>
AuthorDate: Thu, 15 Apr 2010 23:10:42 +0200
Committer: Frederic Weisbecker <fweisbec@xxxxxxxxx>
CommitDate: Fri, 30 Apr 2010 19:15:49 +0200
lockdep: Fix redundant_hardirqs_on incremented with irqs enabled
When a path restore the flags while irqs are already enabled, we
update the per cpu var redundant_hardirqs_on in a racy fashion
and debug_atomic_inc() warns about this situation.
In this particular case, loosing a few hits in a stat is not a big
deal, so increment it without protection.
v2: Don't bother with disabling irq, we can miss one count in
rare situations
Reported-by: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
Signed-off-by: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: David Miller <davem@xxxxxxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
---
kernel/lockdep.c | 7 ++++++-
1 files changed, 6 insertions(+), 1 deletions(-)
diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index 78325f8..1b58a1b 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -2298,7 +2298,12 @@ void trace_hardirqs_on_caller(unsigned long ip)
return;
if (unlikely(curr->hardirqs_enabled)) {
- debug_atomic_inc(redundant_hardirqs_on);
+ /*
+ * Neither irq nor preemption are disabled here
+ * so this is racy by nature but loosing one hit
+ * in a stat is not a big deal.
+ */
+ this_cpu_inc(lockdep_stats.redundant_hardirqs_on);
return;
}
/* we'll do an OFF -> ON transition: */
--
To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
|