From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out203-205-221-153.mail.qq.com (out203-205-221-153.mail.qq.com [203.205.221.153]) (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 13BA5D266 for ; Tue, 30 Jan 2024 01:11:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=203.205.221.153 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706577117; cv=none; b=AyKeQq3PKQGJkMFOETfmMMay5w8+VT5BcXKn42/aOaN6bI+5MkrQF61Jw36I8Ed+UXN1WfyWlvGqBH48ewiOHKoa0mdYXGvFTAhxi5y1BtMQG33r9K9SY8mayWU0iEW8M0fPuris5cMcA9Pszu5kDdNfrQZxFU2+UWJoUqW52qU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706577117; c=relaxed/simple; bh=Q941lI8nlLFQAL+xtX6tHTJm4YMyBQkQpd5pKaj8E60=; h=Message-ID:From:To:Cc:Subject:Date:In-Reply-To:References: MIME-Version; b=cgD5PMz8MWEYfkeZcTChmIhQ1ys48zMbFpxm9+/ss26/+8H3RTJjzVDBmADEoi7Svynv3dYejanRD98sEbgQYNx+E4UNfrsmjyFmDd2uIx4n6ZqYHgy0Q3Tn7bmJZ2eqafZbNUqvm+W4iUUQPe5837ddf3XRNm8O8VVvB2VsMXU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=qq.com; spf=pass smtp.mailfrom=qq.com; dkim=pass (1024-bit key) header.d=qq.com header.i=@qq.com header.b=u0qhlXeD; arc=none smtp.client-ip=203.205.221.153 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=qq.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=qq.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=qq.com header.i=@qq.com header.b="u0qhlXeD" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=qq.com; s=s201512; t=1706576807; bh=Ph+JMqI9QDGLe2tOGODyVREVCb+Ip05RMDj1QLse+9Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=u0qhlXeDg3lOSR4qHQdh//CeQwga4vkz4nNKYEILaaHUmqMcQ55MAHjUUf3za2zqV tpyZnKn/gxTZkshp1OHyrGj12K8dnE6K9/6Wbi14bv2pl1pSxO42Pt2Fyha4gXrCY/ E+VYBR5AW+rk2k3jJDu2+HnWgY3cKMUogY1nfg+8= Received: from pek-lxu-l1.wrs.com ([111.198.225.215]) by newxmesmtplogicsvrszb9-0.qq.com (NewEsmtp) with SMTP id 2BA4CA0; Tue, 30 Jan 2024 09:00:43 +0800 X-QQ-mid: xmsmtpt1706576443t7gnnu2py Message-ID: X-QQ-XMAILINFO: Mdc3TkmnJyI/VlmtfTzmjpgXPDjprb0CBbeC5hHXlW8CUoJ/9pJQ3xWqV/T47B l/yHjGN44KCzu8nj0c+FVLgsPgux7or0SXVs36QDrbPQj2W4/e40fsjcD+1nvaP8GjrlbEWHltPK LrEqugpzGWKMJWz51dWrH4RxflJeFVTWHuFhQcoq8AS2ORJbDU5s8MJAc+N0SmF0FeZnyRNkxooq X2Au4x2fZLLQqEabLIFzrOfou7jwJMaPVw9WJURZ1AgUYuvLPX0heTMLRCvjzaIIbLSCrWxKy6Aj rr+E2edW78ens5nD2pvZaIOiSVApjUWvOYzfMGhmhsMwvGyLjCjqi6pApALBZ/Y8t1Kn8PSRs8eI 0uagTqZpVEg3X4yC0OoYAxM/++DYEo6JOlOCj37tpw7pezEQy/VRoGlLXdM8NuQbNCbA0dS98VFA uEBBGDLdnAZBNbGe/QGb04n/0zTAkW6iOf9tLa+EWhZSf0z0ugPah+FbjnyfITMXeZ+8pddwGdCf YjrUpfwxDdw0znrDYWD0sqUhsqGjnKECENhKmfzhgoTngvUVycRPpljjXK6DpAF1x86lOp4yeb0U qMKPZw8/NOrDk91J021y30NaqlMi1kX+NS9x9dK5cUlFk7OblwyGHiYwRVHDS7hNvnqiKoZGGEal kXEHqKRD97h71bQ1OhQEhifCO3Sqd9y2ECrDmXE+8a2vQTpEw24SY4uagg36v1WTY3KSIRZaLl7L CkJ4givEhsqeCvo0uErEP1lQpOXSjk204oIBM8PCqrPMS5c5cL9LOtvu/vDVui2RDSRsWuxDIbtf 8NMlo7sSjHdHdMAx5c3VAuGuWoDvg21dY85jU/xr6oKhctksqIZtQe2cJJtYW3Zqo7d3Kgd+yHO0 +wugmZ201TjxA4RMxwaKI50gJvwaDPUwWtyBW91AtMKDrr+ESt3gLchtZbJmRcWA== X-QQ-XMRINFO: OD9hHCdaPRBwq3WW+NvGbIU= 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 09:00:44 +0800 X-OQ-MSGID: <20240130010043.3176371-2-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..43af0e72488c 100644 --- a/kernel/trace/blktrace.c +++ b/kernel/trace/blktrace.c @@ -320,8 +320,10 @@ static void blk_trace_free(struct request_queue *q, struct blk_trace *bt) * under 'q->debugfs_dir', thus lookup and remove them. */ if (!bt->dir) { - debugfs_lookup_and_remove("dropped", q->debugfs_dir); - debugfs_lookup_and_remove("msg", q->debugfs_dir); + struct dentry *debugfs_dir = q ? q->debugfs_dir : bt->debugfs_dir; + + debugfs_lookup_and_remove("dropped", debugfs_dir); + debugfs_lookup_and_remove("msg", debugfs_dir); } else { debugfs_remove(bt->dir); } @@ -377,12 +379,23 @@ 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(NULL, bt); + put_probe_ref(); + } +} + static void blk_trace_cleanup(struct request_queue *q, struct blk_trace *bt) { blk_trace_stop(bt); - synchronize_rcu(); - blk_trace_free(q, bt); - put_probe_ref(); + if (!bt->dir) + bt->debugfs_dir = q->debugfs_dir; + call_rcu(&bt->rcu, blk_trace_rcu_free); } 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 *);