From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-co1nam03on0111.outbound.protection.outlook.com ([104.47.40.111]:36928 "EHLO NAM03-CO1-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753200AbeA1W1K (ORCPT ); Sun, 28 Jan 2018 17:27:10 -0500 From: Sasha Levin To: "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" CC: Peter Zijlstra , Linus Torvalds , Thomas Gleixner , "Ingo Molnar" , Sasha Levin Subject: [PATCH AUTOSEL for 4.14 060/100] locking/lockdep: Fix possible NULL deref Date: Sun, 28 Jan 2018 22:26:38 +0000 Message-ID: <20180128222547.7398-60-alexander.levin@microsoft.com> References: <20180128222547.7398-1-alexander.levin@microsoft.com> In-Reply-To: <20180128222547.7398-1-alexander.levin@microsoft.com> Content-Language: en-US Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org List-ID: From: Peter Zijlstra [ Upstream commit 5e351ad106997e06b2dc3da9c6b939b95f67fb88 ] We can't invalidate xhlocks when we've not yet allocated any. Reported-by: Dmitry Vyukov Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Fixes: f52be5708076 ("locking/lockdep: Untangle xhlock history save/restore= from task independence") Signed-off-by: Ingo Molnar Signed-off-by: Sasha Levin --- kernel/locking/lockdep.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index e36e652d996f..dae0d06422a1 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -4780,7 +4780,8 @@ 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)); } =20 static int cross_lock(struct lockdep_map *lock) --=20 2.11.0