From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail115-95.sinamail.sina.com.cn (mail115-95.sinamail.sina.com.cn [218.30.115.95]) (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 6810458AC2 for ; Mon, 29 Jan 2024 10:48:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=218.30.115.95 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706525295; cv=none; b=f9PBGnwDzWvY0cuHX5NCLsaM1J5wPjIMppIgOxsxUGmuz85G498qCw3Et/YDVChaNgH3dnAfUHC/Q7Y31OV0XHzPLpL7HTZUKG4NqqzQsUQ3IlHW0kCr3IFfxS5RlLP96+qhr53Pl+xfIqdnT4oAywara/1hR/+QapldAZdKTB0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706525295; c=relaxed/simple; bh=H8pawYssUx3E0NXxVdNhnMnHUsU90Z8KPRaoaVqfrVw=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=AbHk0bCNiRwN1rbBdlEd1zp4DNMsM/tkp2Q72lA54mlwdfVb/81PvCiXkPoIIREMGEyRG0WE10u1724FIJ0MV163Pl9Fdwkrs20Z+rGTTkTcBMPG5MIMnf4zmXxE4Qrl7tMsnxMwotNI+DsGBb5xbhyj9SXrhZNIaSK9WzU/UDo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=sina.com; spf=pass smtp.mailfrom=sina.com; arc=none smtp.client-ip=218.30.115.95 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=sina.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=sina.com X-SMAIL-HELO: localhost.localdomain Received: from unknown (HELO localhost.localdomain)([116.24.8.153]) by sina.com (172.16.235.24) with ESMTP id 65B78263000077B5; Mon, 29 Jan 2024 18:48:06 +0800 (CST) X-Sender: hdanton@sina.com X-Auth-ID: hdanton@sina.com Authentication-Results: sina.com; spf=none smtp.mailfrom=hdanton@sina.com; dkim=none header.i=none; dmarc=none action=none header.from=hdanton@sina.com X-SMAIL-MID: 53416445089313 X-SMAIL-UIID: 9DD052BF59374A74BB40FD791467B2AB-20240129-184806-1 From: Hillf Danton To: Tetsuo Handa Cc: syzbot , eadavis@qq.com, Peter Zijlstra , Boqun Feng , Linus Torvalds , linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Subject: Re: [syzbot] [bluetooth?] INFO: task hung in hci_conn_failed Date: Mon, 29 Jan 2024 18:47:53 +0800 Message-Id: <20240129104753.1328-1-hdanton@sina.com> In-Reply-To: <4c59b146-df67-48d8-9378-3948dd6fb427@I-love.SAKURA.ne.jp> References: <20240129044824.1218-1-hdanton@sina.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 On Mon, 29 Jan 2024 14:53:20 +0900 Tetsuo Handa wrote: > On 2024/01/29 13:48, Hillf Danton wrote: > >> 3 locks held by kworker/1:2/779: > >> #0: ffff8880b993ccd8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x29/0x130 kernel/sched/core.c:559 > >> #1: ffffc900038c7d80 ((work_completion)(&aux->work)#2){+.+.}-{0:0}, at: process_one_work+0x7eb/0x15d0 kernel/workqueue.c:2609 > >> #2: ffff888052984c80 (&aux->poke_mutex){+.+.}-{3:3}, at: __fd_array_map_delete_elem+0x125/0x2f0 kernel/bpf/arraymap.c:884 > > > > Could locking people shed any light on the failure of detecting the > > poke_mutex with rq lock held? > > > > Showing held locks (lockdep_print_held_locks()) is not a snapshot. > Synchronous printk() can make #0 already released by the moment #2 is taken. > > Please consult printk() people for possibility of making printk() from > lockdep reports (and/or hung task reports) asynchronous. If printk did its work well then we have difficulty explaining why RCU stalled more than two minutes. 6 locks held by kworker/u5:0/51: #0: ffff88802a730d38 ((wq_completion)hci2){+.+.}-{0:0}, at: process_one_work+0x789/0x15d0 kernel/workqueue.c:2608 #1: ffffc90000bc7d80 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_one_work+0x7eb/0x15d0 kernel/workqueue.c:2609 #2: ffff888020989060 (&hdev->req_lock){+.+.}-{3:3}, at: hci_cmd_sync_work+0x170/0x410 net/bluetooth/hci_sync.c:305 #3: ffff888020988078 (&hdev->lock){+.+.}-{3:3}, at: hci_abort_conn_sync+0x150/0xb70 net/bluetooth/hci_sync.c:5337 #4: ffffffff8ef23348 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_connect_cfm include/net/bluetooth/hci_core.h:1983 [inline] #4: ffffffff8ef23348 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_failed+0x158/0x370 net/bluetooth/hci_conn.c:1289 #5: ffffffff8d1b83f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:324 [inline] #5: ffffffff8d1b83f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3ff/0x800 kernel/rcu/tree_exp.h:995