From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932869AbdJKAq6 (ORCPT ); Tue, 10 Oct 2017 20:46:58 -0400 Received: from omzsmtpe02.verizonbusiness.com ([199.249.25.209]:42018 "EHLO omzsmtpe02.verizonbusiness.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932798AbdJKAqy (ORCPT ); Tue, 10 Oct 2017 20:46:54 -0400 From: "Levin, Alexander (Sasha Levin)" X-Host: surveyor.tdc.vzwcorp.com To: "gregkh@linuxfoundation.org" CC: "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" Subject: [GIT PULL for-4.4 01/25] locking/lockdep: Add nest_lock integrity test Thread-Topic: [GIT PULL for-4.4 01/25] locking/lockdep: Add nest_lock integrity test Thread-Index: AQHTQipC6CIbHNhsC0uA5/vbIEfpkg== Date: Wed, 11 Oct 2017 00:45:38 +0000 Message-ID: <20171011004533.8044-2-alexander.levin@verizon.com> References: <20171011004533.8044-1-alexander.levin@verizon.com> In-Reply-To: <20171011004533.8044-1-alexander.levin@verizon.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-messagesentrepresentingtype: 1 x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.144.60.250] Content-Type: text/plain; charset="utf-8" Content-ID: <4186AA5058E63B428FA12A171F8506E5@vzwcorp.com> MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by nfs id v9B0l2wN026620 From: Peter Zijlstra [ Upstream commit 7fb4a2cea6b18dab56d609530d077f168169ed6b ] Boqun reported that hlock->references can overflow. Add a debug test for that to generate a clear error when this happens. Without this, lockdep is likely to report a mysterious failure on unlock. Reported-by: Boqun Feng Signed-off-by: Peter Zijlstra (Intel) Cc: Andrew Morton Cc: Chris Wilson Cc: Linus Torvalds Cc: Nicolai Hähnle Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar Signed-off-by: Sasha Levin --- kernel/locking/lockdep.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 60ace56618f6..0e2c4911ba61 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -3128,10 +3128,17 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, if (depth) { hlock = curr->held_locks + depth - 1; if (hlock->class_idx == class_idx && nest_lock) { - if (hlock->references) + if (hlock->references) { + /* + * Check: unsigned int references:12, overflow. + */ + if (DEBUG_LOCKS_WARN_ON(hlock->references == (1 << 12)-1)) + return 0; + hlock->references++; - else + } else { hlock->references = 2; + } return 1; } -- 2.11.0