Patch "locking/lockdep: Fix possible NULL deref" has been added to the 4.14-stable tree

Patch "locking/lockdep: Fix possible NULL deref" has been added to the 4.14-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    locking/lockdep: Fix possible NULL deref

to the 4.14-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     locking-lockdep-fix-possible-null-deref.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Fri Feb 23 11:45:09 CET 2018
From: Peter Zijlstra <peterz@infradead.org>
Date: Wed, 6 Dec 2017 17:32:47 +0100
Subject: locking/lockdep: Fix possible NULL deref

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)


Patches currently in stable-queue which might be from peterz@infradead.org are

queue-4.14/locking-lockdep-fix-possible-null-deref.patch
queue-4.14/mm-early_ioremap-fix-boot-hang-with-earlyprintk-efi-keep.patch
queue-4.14/perf-fix-header.size-for-namespace-events.patch
queue-4.14/perf-annotate-do-not-truncate-instruction-names-at-6-chars.patch
queue-4.14/x86-mm-kmmio-fix-mmiotrace-for-page-unaligned-addresses.patch