From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out203-205-251-72.mail.qq.com (out203-205-251-72.mail.qq.com [203.205.251.72]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 82DDD65BC9 for ; Tue, 30 Jan 2024 10:59:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=203.205.251.72 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706612391; cv=none; b=YvrOdCTs2l6/tzpQhvzPs6GPG9dC2rtFsXTsFB3CeIA38A4ry7KOV3MXtEGCtmkj8aFtp/vb18OXff8PLl3g1DQm1fCTqWo/xYHnxP3oZxTwtHKRqHgsODzE2xvCKWbEBz9WT/N9SIdUy/+sAIs1HeKOp1QRkNmpN2QCZYj9EXM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706612391; c=relaxed/simple; bh=GB2IybzwCWFKvSFD6TdEeL9jOEQsn9lbMsabAy/BvEk=; h=Message-ID:From:To:Cc:Subject:Date:In-Reply-To:References: MIME-Version; b=XBEPjpbm7nZNag/sAsGYnt21Xg+1lrrMvY5WKjNBFi2x9WvKZzBArvpyjYxa/StlzE5sDWNYSSf93doklkCFyAsMk904gDiNar5orhuf+RonCKxx+p85jIrpPkufwFOSo1sqYaETYWpjV5ElCl71FKf5h4wrYU0HTO7aIt11VVY= ARC-Authentication-Results:i=1; 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Tue, 30 Jan 2024 18:53:43 +0800 X-QQ-mid: xmsmtpt1706612023tdu1foa1s Message-ID: X-QQ-XMAILINFO: MgH8QHUHzFh7ennCN7xTm/B9Ev1wpdoKig/6PQiyPTfqIYNHA7Q660oAk2Ihuy 3UMmkJS3oHraVGekR/msbScZsAOdar30Nm4bYsekg0DQXUThgwgAzrGJeosSg+Q8I5n/rPjcOprn VeoJoZkF7C46zJR6qNCyOSAcj+ZjgKqw5VyVXLiTT7jgaqnCD3z8IDkqnRstkF/Gacg1mf5e4oww r0SHS23soSOts2K5qno8sZyN6JKbN8/ThXvgrzfPxlnRLWPLGP2zWWnWppTUZNmQ4XQ7KihzJcck 5mxHLKaOhA+cM7/V9E5RVWDdOiyg0KazKHlDf0zYq+1tAIjKHVoHn7ti92nZ/iuVieVdd7cGhEvJ W0+0BGMbGVeGuKO9C5QH06puPzljTzbjaK+SzuBbKFjvnE08i+iFKH7nYW+z/0+HCdfpUjZMJFQb TEgzvq99zfyS94/uKbgqL+VnPaw4dgHeogTjMTZlmoW0EjE/orbZ6Hg9MFimcOZgUpn4VjlrFoD0 qC+zIDhtWQSyQJ1bYFCtSWkypXFXoCO3WXh+u66vkZRpd75QqdM1QfTRPi+pkHluZbHIAHFGBvZu b9WkUCJG9ge+Hlc9oNEbYR3LoVmNziXYlvjd1ynUedZKbeuqRwLa3zvyrMlwlwP/M46EPEmvNv5a pETI1dQX1+VjpPgv475tI8lnQ7HxkfNg8cxo9gFeb86l+y1pno+Yz3OlfcMlTL+efbAIxFwkHv8l xJYXNkv1H3+M22AKuOsXkEX5lfLdOCbTZzFvVF6zT1LkXi3e/Ca6a3FxN0LhDf38DD0RtUen1xKV Bcvy8nCvosgihS6YEuyQbGudK3i5RTp9yOPHNhjqL+EY411esO6E9MG3NQeY/lKfv8UKav/j4+3W DVRwj1cIF+K5VYF3gKvbRRgqKy9p1sVrrohpqgpE+Hu1UAyL0Iofxo5wX8HEir2JORb4cHkY4dRu xrbDqTr5Zw0UQhBihvlSua4ZKq2TEe X-QQ-XMRINFO: Nq+8W0+stu50PRdwbJxPCL0= From: Edward Adam Davis To: syzbot+2373f6be3e6de4f92562@syzkaller.appspotmail.com Cc: linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Subject: Re: [syzbot] [block?] [trace?] INFO: task hung in blk_trace_remove (2) Date: Tue, 30 Jan 2024 18:53:43 +0800 X-OQ-MSGID: <20240130105342.3944585-2-eadavis@qq.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <0000000000002b1fc7060fca3adf@google.com> References: <0000000000002b1fc7060fca3adf@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit please test task hung in blk_trace_remove #syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c index d5d94510afd3..f3d02bf98a80 100644 --- a/kernel/trace/blktrace.c +++ b/kernel/trace/blktrace.c @@ -330,6 +330,13 @@ static void blk_trace_free(struct request_queue *q, struct blk_trace *bt) kfree(bt); } +static void blk_trace_free_rcu(struct blk_trace *bt) +{ + free_percpu(bt->sequence); + free_percpu(bt->msg_data); + kfree(bt); +} + static void get_probe_ref(void) { mutex_lock(&blk_probe_mutex); @@ -377,12 +384,36 @@ static int blk_trace_stop(struct blk_trace *bt) return 0; } +static void blk_trace_rcu_free(struct rcu_head *rcu) +{ + struct blk_trace *bt; + + bt = container_of(rcu, struct blk_trace, rcu); + if (bt) { + blk_trace_free_rcu(bt); + } +} + static void blk_trace_cleanup(struct request_queue *q, struct blk_trace *bt) { blk_trace_stop(bt); - synchronize_rcu(); - blk_trace_free(q, bt); + if (!bt->dir) + bt->debugfs_dir = q->debugfs_dir; + mutex_unlock(&q->debugfs_mutex); + relay_close(bt->rchan); + /* + * If 'bt->dir' is not set, then both 'dropped' and 'msg' are created + * under 'q->debugfs_dir', thus lookup and remove them. + */ + if (!bt->dir) { + debugfs_lookup_and_remove("dropped", bt->debugfs_dir); + debugfs_lookup_and_remove("msg", bt->debugfs_dir); + } else { + debugfs_remove(bt->dir); + } put_probe_ref(); + call_rcu(&bt->rcu, blk_trace_rcu_free); + mutex_lock(&q->debugfs_mutex); } static int __blk_trace_remove(struct request_queue *q) diff --git a/include/linux/blktrace_api.h b/include/linux/blktrace_api.h index 122c62e561fc..4920c201bd12 100644 --- a/include/linux/blktrace_api.h +++ b/include/linux/blktrace_api.h @@ -26,6 +26,8 @@ struct blk_trace { struct dentry *dir; struct list_head running_list; atomic_t dropped; + struct dentry *debugfs_dir; + struct rcu_head rcu; }; extern int blk_trace_ioctl(struct block_device *, unsigned, char __user *);