From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 10842C76195 for ; Mon, 15 Jul 2019 14:21:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D93B821530 for ; Mon, 15 Jul 2019 14:21:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563200462; bh=zvVaimIqmMtPFymMmSVC+XhJocKCIfsY7KZqvrpIHFU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=KqK6m48xErUwbht869B7n00KVwUgHdCr2o1C3C3aAVDIY2d+XDr7mjbpFDXgzygn1 iXUyeWyWRE1NZlRZd/tuU05r32VhYAT8gbEOZpAc/CFBEceX+nw9KpZELnFbvDmYru nMnVd3Xq2ibNF++pTve6HqLbHNxerm3d30TZOt+w= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390478AbfGOOVB (ORCPT ); Mon, 15 Jul 2019 10:21:01 -0400 Received: from mail.kernel.org ([198.145.29.99]:42634 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390196AbfGOOT5 (ORCPT ); Mon, 15 Jul 2019 10:19:57 -0400 Received: from sasha-vm.mshome.net (unknown [73.61.17.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7F83B217D8; Mon, 15 Jul 2019 14:19:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563200396; bh=zvVaimIqmMtPFymMmSVC+XhJocKCIfsY7KZqvrpIHFU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=WhrcpfRhsfVjnxWHWQz4taafQhMW7v259EEWm2Yc24naecVz2zRupe8m+7+hEGPkv /9dTNr3Sme3rNPbReoPvFFta6G4iNJTYFHW9aKoFVGTTz43NwIQU62dAL4gMZ8qrqu 9k6KiJD4DzCPb9nSNhz6mR25B6AB3n2qohKN1KkU= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Imre Deak , Peter Zijlstra , =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= , Linus Torvalds , Thomas Gleixner , Will Deacon , Ingo Molnar , Sasha Levin Subject: [PATCH AUTOSEL 4.19 037/158] locking/lockdep: Fix merging of hlocks with non-zero references Date: Mon, 15 Jul 2019 10:16:08 -0400 Message-Id: <20190715141809.8445-37-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190715141809.8445-1-sashal@kernel.org> References: <20190715141809.8445-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Imre Deak [ Upstream commit d9349850e188b8b59e5322fda17ff389a1c0cd7d ] The sequence static DEFINE_WW_CLASS(test_ww_class); struct ww_acquire_ctx ww_ctx; struct ww_mutex ww_lock_a; struct ww_mutex ww_lock_b; struct ww_mutex ww_lock_c; struct mutex lock_c; ww_acquire_init(&ww_ctx, &test_ww_class); ww_mutex_init(&ww_lock_a, &test_ww_class); ww_mutex_init(&ww_lock_b, &test_ww_class); ww_mutex_init(&ww_lock_c, &test_ww_class); mutex_init(&lock_c); ww_mutex_lock(&ww_lock_a, &ww_ctx); mutex_lock(&lock_c); ww_mutex_lock(&ww_lock_b, &ww_ctx); ww_mutex_lock(&ww_lock_c, &ww_ctx); mutex_unlock(&lock_c); (*) ww_mutex_unlock(&ww_lock_c); ww_mutex_unlock(&ww_lock_b); ww_mutex_unlock(&ww_lock_a); ww_acquire_fini(&ww_ctx); (**) will trigger the following error in __lock_release() when calling mutex_release() at **: DEBUG_LOCKS_WARN_ON(depth <= 0) The problem is that the hlock merging happening at * updates the references for test_ww_class incorrectly to 3 whereas it should've updated it to 4 (representing all the instances for ww_ctx and ww_lock_[abc]). Fix this by updating the references during merging correctly taking into account that we can have non-zero references (both for the hlock that we merge into another hlock or for the hlock we are merging into). Signed-off-by: Imre Deak Signed-off-by: Peter Zijlstra (Intel) Cc: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Will Deacon Link: https://lkml.kernel.org/r/20190524201509.9199-2-imre.deak@intel.com Signed-off-by: Ingo Molnar Signed-off-by: Sasha Levin --- kernel/locking/lockdep.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 26b57e24476f..e810e8cb17e1 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -3326,17 +3326,17 @@ 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) { - /* - * Check: unsigned int references:12, overflow. - */ - if (DEBUG_LOCKS_WARN_ON(hlock->references == (1 << 12)-1)) - return 0; + if (!references) + references++; + if (!hlock->references) hlock->references++; - } else { - hlock->references = 2; - } + + hlock->references += references; + + /* Overflow */ + if (DEBUG_LOCKS_WARN_ON(hlock->references < references)) + return 0; return 1; } -- 2.20.1