From nobody Tue May 14 09:55:09 2024 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=pass; 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; dmarc=pass(p=none dis=none) header.from=redhat.com ARC-Seal: i=1; a=rsa-sha256; t=1683122529; cv=none; d=zohomail.com; s=zohoarc; b=lUY9Mos/kBrBwkiQxtA55DKxibL2HQOOX9YrCU1R2p38+Oew/+n9Hq3Xwlz3UeMF23PJp0SUyNkc7d7dCJp3ten/f5nMHFitMuIakN/3ZAbIIBeQ2tZv0iIsGuNymrtKfTIqsYubEpyEBzJ9hNu08eDM3KAShHH8CiuPpaA9ZDA= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1683122529; h=Content-Transfer-Encoding:Cc:Date:From:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:Sender:Subject:To; bh=6NhsBJr2pi062KXhnbLfmOoLQAj3luaAICcAXzD8gwg=; b=m9areeCSH6p/ulC3bRWtMprcBtmRyLuFPS429xvIEFv92KofQLZCoDizTCI02GogB1h+SfytYjuXl2JfySRcdzLtteuRPUb8miTvupLWMyZ8KMI+LmjN4gfU9prTmSK1W73TOih3G87dauiQGgKxzfa1I98nM9mo+T30pgbC1To= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; 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; dmarc=pass header.from= (p=none dis=none) Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1683122529536217.8273818888532; Wed, 3 May 2023 07:02:09 -0700 (PDT) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1puD3I-0002cF-1q; Wed, 03 May 2023 10:01:52 -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 1puD3G-0002at-Hk for qemu-devel@nongnu.org; Wed, 03 May 2023 10:01:50 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1puD3F-0003Xs-4d for qemu-devel@nongnu.org; Wed, 03 May 2023 10:01:50 -0400 Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-323-T_Rpr7niNyeKGKUYHI4PmQ-1; Wed, 03 May 2023 10:01:45 -0400 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 34A7B85D540; Wed, 3 May 2023 14:01:45 +0000 (UTC) Received: from merkur.str.redhat.com (dhcp-192-205.str.redhat.com [10.33.192.205]) by smtp.corp.redhat.com (Postfix) with ESMTP id 7EAF51410F29; Wed, 3 May 2023 14:01:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1683122508; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=6NhsBJr2pi062KXhnbLfmOoLQAj3luaAICcAXzD8gwg=; b=H/3TngdLfs7oFzZJd/iFlPoEPl9PKDlN7/hQwm4Xiob6gY1a/wuuOBu6958Eh4bFGDBbTA dqY8VJmdNdtfXRpGKkUJn3XMTW3TeltDLwyhmX6t6BiDHaBFgOjpx0S1H3y+8/4jyh8ceP 3uGc+l34LPJxgWWhRI5h/XA0f23nm8M= X-MC-Unique: T_Rpr7niNyeKGKUYHI4PmQ-1 From: Kevin Wolf To: qemu-block@nongnu.org Cc: kwolf@redhat.com, stefanha@redhat.com, qemu-devel@nongnu.org Subject: [PATCH] block: Fix use after free in blockdev_mark_auto_del() Date: Wed, 3 May 2023 16:01:42 +0200 Message-Id: <20230503140142.474404-1-kwolf@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.1 on 10.11.54.7 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=170.10.129.124; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -22 X-Spam_score: -2.3 X-Spam_bar: -- X-Spam_report: (-2.3 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.161, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=unavailable 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-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1683122533522100001 Content-Type: text/plain; charset="utf-8" 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). Signed-off-by: Kevin Wolf Reviewed-by: Stefan Hajnoczi --- blockdev.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) diff --git a/blockdev.c b/blockdev.c index d7b5c18f0a..2c1752a403 100644 --- a/blockdev.c +++ b/blockdev.c @@ -153,12 +153,22 @@ 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 2.40.1