From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from firstgate.proxmox.com (firstgate.proxmox.com [212.224.123.68]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by lists.proxmox.com (Postfix) with ESMTPS id E560172F99 for ; Wed, 25 May 2022 14:00:13 +0200 (CEST) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with ESMTP id DAD072AABC for ; Wed, 25 May 2022 13:59:43 +0200 (CEST) Received: from proxmox-new.maurer-it.com (proxmox-new.maurer-it.com [94.136.29.106]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by firstgate.proxmox.com (Proxmox) with ESMTPS id F173E2AAA6 for ; Wed, 25 May 2022 13:59:42 +0200 (CEST) Received: from proxmox-new.maurer-it.com (localhost.localdomain [127.0.0.1]) by proxmox-new.maurer-it.com (Proxmox) with ESMTP id BF5C043854 for ; Wed, 25 May 2022 13:59:42 +0200 (CEST) From: Fabian Ebner To: pve-devel@lists.proxmox.com Date: Wed, 25 May 2022 13:59:38 +0200 Message-Id: <20220525115939.347193-2-f.ebner@proxmox.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220525115939.347193-1-f.ebner@proxmox.com> References: <20220525115939.347193-1-f.ebner@proxmox.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SPAM-LEVEL: Spam detection results: 0 AWL 0.067 Adjusted score from AWL reputation of From: address BAYES_00 -1.9 Bayes spam probability is 0 to 1% KAM_DMARC_STATUS 0.01 Test Rule for DKIM or SPF Failure with Strict Alignment SPF_HELO_NONE 0.001 SPF: HELO does not publish an SPF Record SPF_PASS -0.001 SPF: sender matches SPF record T_SCC_BODY_TEXT_LINE -0.01 - Subject: [pve-devel] [RFC/PATCH v2 qemu 2/3] PVE-Backup: ensure jobs in di_list are referenced X-BeenThere: pve-devel@lists.proxmox.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: Proxmox VE development discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 25 May 2022 12:00:13 -0000 Ensures that qmp_backup_cancel doesn't pick a job that's already been freed. With unlucky timings it seems possible that: 1. job_exit -> job_completed -> job_finalize_single starts 2. pvebackup_co_complete_stream gets spawned in completion callback 3. job finalize_single finishes -> job's refcount hits zero -> job is freed 4. qmp_backup_cancel comes in and locks backup_state.backup_mutex before pvebackup_co_complete_stream can remove the job from the di_list 5. qmp_backup_cancel will pick a job that's already been freed Signed-off-by: Fabian Ebner --- New in v2. pve-backup.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/pve-backup.c b/pve-backup.c index dfaf4c93f8..3cede98b1d 100644 --- a/pve-backup.c +++ b/pve-backup.c @@ -314,6 +314,11 @@ static void coroutine_fn pvebackup_co_complete_stream(void *opaque) } } + if (di->job) { + job_unref(&di->job->job); + di->job = NULL; + } + // remove self from job list backup_state.di_list = g_list_remove(backup_state.di_list, di); @@ -497,6 +502,9 @@ static void create_backup_jobs_bh(void *opaque) { aio_context_release(aio_context); di->job = job; + if (job) { + job_ref(&job->job); + } if (!job || local_err) { error_setg(errp, "backup_job_create failed: %s", @@ -531,6 +539,11 @@ static void create_backup_jobs_bh(void *opaque) { aio_context_release(ctx); canceled = true; } + + if (di->job) { + job_unref(&di->job->job); + di->job = NULL; + } } } -- 2.30.2