4.14-stable review patch.  If anyone has any objections, please let me know.


From: Peter Zijlstra <pet...@infradead.org>

[ Upstream commit 5e351ad106997e06b2dc3da9c6b939b95f67fb88 ]

We can't invalidate xhlocks when we've not yet allocated any.

Reported-by: Dmitry Vyukov <dvyu...@google.com>
Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Fixes: f52be5708076 ("locking/lockdep: Untangle xhlock history save/restore 
from task independence")
Signed-off-by: Ingo Molnar <mi...@kernel.org>
Signed-off-by: Sasha Levin <alexander.le...@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
 kernel/locking/lockdep.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -4777,7 +4777,8 @@ void lockdep_invariant_state(bool force)
         * Verify the former, enforce the latter.
        WARN_ON_ONCE(!force && current->lockdep_depth);
-       invalidate_xhlock(&xhlock(current->xhlock_idx));
+       if (current->xhlocks)
+               invalidate_xhlock(&xhlock(current->xhlock_idx));
 static int cross_lock(struct lockdep_map *lock)

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