| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.14 117/159] locking/lockdep: Fix possible NULL deref | Date | Fri, 23 Feb 2018 19:27:05 +0100 |
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4.14-stable review patch. If anyone has any objections, please let me know.
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From: Peter Zijlstra <peterz@infradead.org>
[ Upstream commit 5e351ad106997e06b2dc3da9c6b939b95f67fb88 ]
We can't invalidate xhlocks when we've not yet allocated any.
Reported-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@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 <mingo@kernel.org> Signed-off-by: Sasha Levin <alexander.levin@verizon.com> Signed-off-by: Greg Kroah-Hartman <gregkh@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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