From nobody Mon Feb 9 18:45:18 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1684314752417688.0567247480884; Wed, 17 May 2023 02:12:32 -0700 (PDT) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pzDCZ-0002b1-Kr; Wed, 17 May 2023 05:12:09 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pzDBj-0000wC-Qy; Wed, 17 May 2023 05:11:15 -0400 Received: from isrv.corpit.ru ([86.62.121.231]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pzDBh-0006PQ-Nk; Wed, 17 May 2023 05:11:15 -0400 Received: from tsrv.corpit.ru (tsrv.tls.msk.ru [192.168.177.2]) by isrv.corpit.ru (Postfix) with ESMTP id 845EC6837; Wed, 17 May 2023 12:10:45 +0300 (MSK) Received: from tls.msk.ru (mjt.wg.tls.msk.ru [192.168.177.130]) by tsrv.corpit.ru (Postfix) with SMTP id E9A0E5F08; Wed, 17 May 2023 12:10:44 +0300 (MSK) Received: (nullmailer pid 3626717 invoked by uid 1000); Wed, 17 May 2023 09:10:42 -0000 From: Michael Tokarev To: qemu-stable@nongnu.org Cc: qemu-devel@nongnu.org, Kevin Wolf , Stefan Hajnoczi Subject: [PATCH v7.2.3 17/30] block: Fix use after free in blockdev_mark_auto_del() Date: Wed, 17 May 2023 12:10:29 +0300 Message-Id: <20230517091042.3626593-17-mjt@msgid.tls.msk.ru> X-Mailer: git-send-email 2.39.2 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=86.62.121.231; envelope-from=mjt@tls.msk.ru; helo=isrv.corpit.ru X-Spam_score_int: -68 X-Spam_score: -6.9 X-Spam_bar: ------ X-Spam_report: (-6.9 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_HI=-5, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZM-MESSAGEID: 1684314752588100001 Content-Type: text/plain; charset="utf-8" From: Kevin Wolf job_cancel_locked() drops the job list lock temporarily and it may call aio_poll(). We must assume that the list has changed after this call. Also, with unlucky timing, it can end up freeing the job during job_completed_txn_abort_locked(), making the job pointer invalid, too. For both reasons, we can't just continue at block_job_next_locked(job). Instead, start at the head of the list again after job_cancel_locked() and skip those jobs that we already cancelled (or that are completing anyway). Cc: qemu-stable@nongnu.org Signed-off-by: Kevin Wolf Reviewed-by: Stefan Hajnoczi Signed-off-by: Kevin Wolf (cherry picked from commit e2626874a32602d4e52971c786ef5ffb4430629d) Signed-off-by: Michael Tokarev --- blockdev.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) diff --git a/blockdev.c b/blockdev.c index 3f1dec6242..ae27a41efa 100644 --- a/blockdev.c +++ b/blockdev.c @@ -152,12 +152,22 @@ void blockdev_mark_auto_del(BlockBackend *blk) =20 JOB_LOCK_GUARD(); =20 - for (job =3D block_job_next_locked(NULL); job; - job =3D block_job_next_locked(job)) { - if (block_job_has_bdrv(job, blk_bs(blk))) { + do { + job =3D block_job_next_locked(NULL); + while (job && (job->job.cancelled || + job->job.deferred_to_main_loop || + !block_job_has_bdrv(job, blk_bs(blk)))) + { + job =3D block_job_next_locked(job); + } + if (job) { + /* + * This drops the job lock temporarily and polls, so we need to + * restart processing the list from the start after this. + */ job_cancel_locked(&job->job, false); } - } + } while (job); =20 dinfo->auto_del =3D 1; } --=20 2.39.2