From patchwork Thu May 4 19:53:07 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Hajnoczi X-Patchwork-Id: 13231704 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 59AC8C7EE21 for ; Thu, 4 May 2023 19:53:58 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.530061.825336 (Exim 4.92) (envelope-from ) id 1puf1L-0003zZ-Nx; Thu, 04 May 2023 19:53:43 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 530061.825336; Thu, 04 May 2023 19:53:43 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1puf1L-0003zS-JB; Thu, 04 May 2023 19:53:43 +0000 Received: by outflank-mailman (input) for mailman id 530061; Thu, 04 May 2023 19:53:42 +0000 Received: from se1-gles-flk1-in.inumbo.com ([94.247.172.50] helo=se1-gles-flk1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1puf1K-0003xx-MF for xen-devel@lists.xenproject.org; Thu, 04 May 2023 19:53:42 +0000 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by se1-gles-flk1.inumbo.com (Halon) with ESMTPS id 5cb4c55b-eab5-11ed-8611-37d641c3527e; Thu, 04 May 2023 21:53:39 +0200 (CEST) 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-558-qVm4RSmtOvC22VNK6fWUTQ-1; Thu, 04 May 2023 15:53:34 -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 50FFE101A550; Thu, 4 May 2023 19:53:33 +0000 (UTC) Received: from localhost (unknown [10.39.192.57]) by smtp.corp.redhat.com (Postfix) with ESMTP id 78E421410F29; Thu, 4 May 2023 19:53:32 +0000 (UTC) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 5cb4c55b-eab5-11ed-8611-37d641c3527e DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1683230018; 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: in-reply-to:in-reply-to:references:references; bh=7t7uQFODUsT7GUPKJzVAstWb4vuQdfLqZNy3S4rp+B4=; b=L1ntaQo24O9SYlpe8zmaJ8bo+st/9Q4rwHvj9Zrg8zQnW+ojLaaZQR/FR29jZveEx5Cilv QzWLdGbDJPbRHtkckNKB1ACx9X1I6FV57xGjT0oU3UCV3UF2JKazquhOytbUIQeTe1BrL6 F3A4stphdxrZNMpMl0U1dKu65r7kWLM= X-MC-Unique: qVm4RSmtOvC22VNK6fWUTQ-1 From: Stefan Hajnoczi To: qemu-devel@nongnu.org Cc: Ronnie Sahlberg , Aarushi Mehta , qemu-block@nongnu.org, Paul Durrant , Anthony Perard , Peter Lieven , Stefan Weil , Xie Yongji , Kevin Wolf , Paolo Bonzini , "Michael S. Tsirkin" , Leonardo Bras , Peter Xu , Hanna Reitz , Stefano Stabellini , Richard Henderson , David Woodhouse , Coiby Xu , Eduardo Habkost , Stefano Garzarella , =?utf-8?q?Philippe_Mathieu-Daud?= =?utf-8?q?=C3=A9?= , =?utf-8?q?Daniel_P=2E_Berrang=C3=A9?= , Stefan Hajnoczi , Julia Suvorova , xen-devel@lists.xenproject.org, eesposit@redhat.com, Juan Quintela , "Richard W.M. Jones" , Fam Zheng , Marcel Apfelbaum Subject: [PATCH v5 01/21] block: Fix use after free in blockdev_mark_auto_del() Date: Thu, 4 May 2023 15:53:07 -0400 Message-Id: <20230504195327.695107-2-stefanha@redhat.com> In-Reply-To: <20230504195327.695107-1-stefanha@redhat.com> References: <20230504195327.695107-1-stefanha@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.7 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). Signed-off-by: Kevin Wolf Reviewed-by: Stefan Hajnoczi Signed-off-by: Stefan Hajnoczi Message-Id: <20230503140142.474404-1-kwolf@redhat.com> --- 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) JOB_LOCK_GUARD(); - for (job = block_job_next_locked(NULL); job; - job = block_job_next_locked(job)) { - if (block_job_has_bdrv(job, blk_bs(blk))) { + do { + job = 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 = 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); dinfo->auto_del = 1; }