From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out203-205-221-235.mail.qq.com (out203-205-221-235.mail.qq.com [203.205.221.235]) (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 42B7459147 for ; Tue, 30 Jan 2024 08:43:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=203.205.221.235 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706604239; cv=none; b=YBv1kjAPeb7SkBixr3idR3TqXgDMg9dk7Klu64ROFrfzdwY7cre7wTXdRWkg/Qbqdp4xjhVf5bI43W/xOFO2gfjohz5OJ+4QCvAPnaGxbbTYuzebFnBEkpvK55l2igx+QBHGHuKSPrl/jfzyN5smiFGt0/mcA1eRUCsDz7GKWDI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706604239; c=relaxed/simple; bh=a/doanRbOKE9y+h32FzGqbaLaL/blaSzrUB9qFpcO1s=; h=Message-ID:From:To:Cc:Subject:Date:In-Reply-To:References: MIME-Version; b=k83Y4ObpSPAy4ZYQz0AMqUK6eqmTH65U/8ZbuO8D40NbRvKmqDkFObmtNWKx2JLhFxm1uepj8OxkCynMXYcex0mS7d7t47xdBvpQOFkAJ5VEOD/KOWxszRK18VQYWgSoT/Q98huMqo57pOaGUddkBE6D2v4nh92hQpePBMKK/pg= ARC-Authentication-Results:i=1; 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Tue, 30 Jan 2024 16:37:48 +0800 X-QQ-mid: xmsmtpt1706603868trena0m28 Message-ID: X-QQ-XMAILINFO: NDgMZBR9sMmaP+1mcOH883vPeZzBnKYBWWgdNLkSMZHEAobah0jl9oXTYD9hVp 2T9uQPc9bqUnH5dlW6XgA3ib+sUf+VhUseeLTADNCJ99T1G9yLhxS5x3aqffeWJaMeWvl0LXtp/Y Dk38L48K8luGIRiuom/6drCZpwKT5nArSHU4tFgDgMDtUNRWk12IInEopBaVytS6HobalTjZ2unF PIUoz+TkmCnC2EX2Z4iLl6LSb36H/FB4wjDasMBeleZubwXOIdOXXoqlgZJ3GTldhWhfkIzRVzG4 cp/uSOcldGZseYrlcPGonn26+r+nHeJJnvPX7cjujI8viqmKa5yK/Skk8m/I5WHRJx7nHXTw/vPb xocwUhpR9IB3K8z754M8GzR+RghK9fvNSfjNK4Pu23HAqucRVqJpyJYgZ+KI80Hy3AMa3dO7NItA yAOQu8KARF4A8I4YpN333OYM5Wt4AI5pWG1j29v83eK7Ku7ibMWZhp1LEoq5fJ/2++9X+dc3T9/0 Uy4kpaFdme3gO4GoROngTC+NBpxZvVRjhDh8u9kW7SrMdxrHNR3YGbwLxSPgaf1QqWeonUNZ1vz6 fZF8o1R7QqcjpnlDCHJrrREL2+SeGUaC0FyAtp/XZObWrrCYRossXIAfLmX+0jfDfw3GEOCdkQg9 wFpyFrr/MgiInpZtLlm7wuNMGxa8IM8Cfiuejr6kuVCxch3Z6MhdFcrfrZTlhB5CTLGS79lY//Nn 2E0JD11qH4yF/U+mMqT3YwSkBNPbklxg3/gh6h4xuvyYX5N458bNOjqH2z67v6SdP8XDwJdXVIIY 9UnsHd4C6RUtgVPkvDWHRKC18OwNfqbzMdfKohS+oYGUSkw2yHvK9rDdpbOoUFADRtBxP1xgRYBN yja8rIbA/6IKU3PLZzgrn/tA1KM+RfSFSFKd+Q7doA9Jf0C88Muud2D90jUs7RUUARWMraJMpx 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 16:37:49 +0800 X-OQ-MSGID: <20240130083748.3760265-2-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..9575f19d390d 100644 --- a/kernel/trace/blktrace.c +++ b/kernel/trace/blktrace.c @@ -330,6 +330,23 @@ 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) +{ + /* + * 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); + } + free_percpu(bt->sequence); + free_percpu(bt->msg_data); + kfree(bt); +} + static void get_probe_ref(void) { mutex_lock(&blk_probe_mutex); @@ -377,12 +394,26 @@ 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); + 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; + mutex_unlock(&q->debugfs_mutex); + relay_close(bt->rchan); + 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 *);