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From devnull@lkml.org Tue Apr 23 17:55:38 2024 >From mailfetcher Thu May 3 09:43:20 2018 Envelope-to: lkml@grols.ch Delivery-date: Thu, 03 May 2018 09:43:19 +0200 Received: from srv.grols.ch [5.172.41.101] by 1eb738dfd482 with IMAP (fetchmail-6.3.26) for (single-drop); Thu, 03 May 2018 09:43:20 +0200 (CEST) Received: from vger.kernel.org ([209.132.180.67]) by home.grols.ch with esmtp (Exim 4.89) (envelope-from ) id 1fE8TP-0000pU-6c for lkml@grols.ch; Thu, 03 May 2018 09:16:16 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751166AbeECFp5 (ORCPT ); Thu, 3 May 2018 01:45:57 -0400 Received: from www262.sakura.ne.jp ([202.181.97.72]:44393 "EHLO www262.sakura.ne.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751224AbeECFp4 (ORCPT ); Thu, 3 May 2018 01:45:56 -040 Received: from fsav402.sakura.ne.jp (fsav402.sakura.ne.jp [133.242.250.101]) by www262.sakura.ne.jp (8.14.5/8.14.5) with ESMTP id w435jX7D026581; Thu, 3 May 2018 14:45:33 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) Received: from www262.sakura.ne.jp (202.181.97.72) by fsav402.sakura.ne.jp (F-Secure/fsigk_smtp/530/fsav402.sakura.ne.jp); Thu, 03 May 2018 14:45:33 +0900 (JST) X-Virus-Status: clean(F-Secure/fsigk_smtp/530/fsav402.sakura.ne.jp) Received: from [192.168.1.8] (softbank126099184120.bbtec.net [126.99.184.120]) (authenticated bits=0) by www262.sakura.ne.jp (8.14.5/8.14.5) with ESMTP id w435jPhj026534 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Subject: Re: INFO: rcu detected stall in __schedule To: syzbot , syzkaller-bugs@googlegroups.com, dvyukov@google.com References: <000000000000d2fe62056b3ccca5@google.com> From: Tetsuo Handa Cc: linux-kernel@vger.kernel.org, linux-ppp@vger.kernel.org, netdev@vger.kernel.org, paulus@samba.org Message-Id: <1356afb7-80cf-d9d9-c282-e4e819807376@I-love.SAKURA.ne.jp> Date: Thu, 3 May 2018 14:45:24 +0900 User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 Mime-Version: 1.0 In-Reply-To: <000000000000d2fe62056b3ccca5@google.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-Id: X-Mailing-List: linux-kernel@vger.kernel.org Received-SPF: none client-ip=209.132.180.67; envelope-from=linux-kernel-owner@vger.kernel.org; helo=vger.kernel.org X-Spam-Score: 4.7 X-Spam-Score-Bar: ++++ X-Spam-Action: no action X-Spam-Report: Action: no action Symbol: RCVD_COUNT_FIVE(0.00) Symbol: MID_RHS_MATCH_FROM(0.00) Symbol: GREYLIST(0.00) Symbol: RCVD_NO_TLS_LAST(0.00) Symbol: R_SPF_NA(0.00) Symbol: FROM_NEQ_ENVFROM(0.00) Symbol: FROM_HAS_DN(0.00) Symbol: RCPT_COUNT_SEVEN(0.00) Symbol: I'm not sure whether this is a PPP bug. As of uptime = 484, RCU says that it stalled for 125 seconds. ---------- [ 484.407032] INFO: rcu_sched self-detected stall on CPU [ 484.412488] 0-...!: (125000 ticks this GP) idle=f3e/1/4611686018427387906 softirq=112858/112858 fqs=0 [ 484.422300] (t=125000 jiffies g=61626 c=61625 q=1534) [ 484.427663] rcu_sched kthread starved for 125000 jiffies! g61626 c61625 f0x0 RCU_GP_WAIT_FQS(3) ->state=0x402 ->cpu=0 ---------- 484 - 125 = 359, which was about to start SND related fuzzing in that log. ---------- 2033/05/18 03:36:31 executing program 1: r0 = socket(0x40000a, 0x5, 0x7) setsockopt$inet_int(r0, 0x0, 0x18, &(0x7f0000000000)=0x200, 0x4) bind$inet6(r0, &(0x7f00000000c0)={0xa, 0x0, 0x0, @loopback={0x0, 0x1}}, 0x1c) perf_event_open(&(0x7f0000000040)={0x2, 0x70, 0x3e5}, 0x0, 0xffffffffffffffff, 0xffffffffffffffff, 0x0) timer_create(0x0, &(0x7f00000001c0)={0x0, 0x15, 0x0, @thr={&(0x7f0000000440), &(0x7f0000000540)}}, &(0x7f0000000200)) timer_getoverrun(0x0) perf_event_open(&(0x7f000025c000)={0x2, 0x78, 0x3e3}, 0x0, 0x0, 0xffffffffffffffff, 0x0) r1 = syz_open_dev$sndctrl(&(0x7f0000000200)='/dev/snd/controlC#\x00', 0x2, 0x0) perf_event_open(&(0x7f0000001000)={0x0, 0x70, 0x0, 0x0, 0x0, 0x0, 0x0, 0x8ce, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x7, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0xfffffffffffffff8, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, @perf_bp={&(0x7f0000005000), 0x2}, 0x1000000000c}, 0x0, 0x0, 0xffffffffffffffff, 0x0) ioctl$SNDRV_CTL_IOCTL_SUBSCRIBE_EVENTS(r1, 0xc0045516, &(0x7f00000000c0)=0x1) r2 = syz_open_dev$sndpcmp(&(0x7f0000000100)='/dev/snd/pcmC#D#p\x00', 0x1, 0x4000) ioctl$SNDRV_SEQ_IOCTL_GET_QUEUE_CLIENT(r2, 0xc04c5349, &(0x7f0000000240)={0x200, 0xfffffffffffffcdc, 0x1}) syz_open_dev$tun(&(0x7f00000003c0)='/dev/net/tun\x00', 0x0, 0x20402) ioctl$SNDRV_CTL_IOCTL_PVERSION(r1, 0xc1105517, &(0x7f0000001000)=""/250) ioctl$SNDRV_CTL_IOCTL_SUBSCRIBE_EVENTS(r1, 0xc0045516, &(0x7f0000000000)) 2033/05/18 03:36:31 executing program 4: syz_emit_ethernet(0x3e, &(0x7f00000000c0)={@broadcast=[0xff, 0xff, 0xff, 0xff, 0xff, 0xff], @empty=[0x0, 0x0, 0xb00000000000000], [], {@ipv4={0x800, {{0x5, 0x4, 0x0, 0x0, 0x30, 0x0, 0x0, 0x0, 0x1, 0x0, @remote={0xac, 0x14, 0x14, 0xbb}, @dev={0xac, 0x14, 0x14}}, @icmp=@parameter_prob={0x5, 0x4, 0x0, 0x0, 0x0, 0x0, {0x5, 0x4, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, @local={0xac, 0x223, 0x14, 0xaa}, @dev={0xac, 0x14, 0x14}}}}}}}, &(0x7f0000000000)={0x0, 0x2, [0x0, 0x2e6]}) 2033/05/18 03:36:31 executing program 1: r0 = socket$pppoe(0x18, 0x1, 0x0) connect$pppoe(r0, &(0x7f00000000c0)={0x18, 0x0, {0x1, @broadcast=[0xff, 0xff, 0xff, 0xff, 0xff, 0xff], 'ip6_vti0\x00'}}, 0x1e) r1 = socket(0x3, 0xb, 0x80000001) setsockopt$inet_sctp6_SCTP_ADAPTATION_LAYER(r1, 0x84, 0x7, &(0x7f0000000100)={0x2}, 0x4) ioctl$sock_inet_SIOCGIFADDR(r0, 0x8915, &(0x7f0000000040)={'veth1_to_bridge\x00', {0x2, 0x4e21}}) r2 = syz_open_dev$admmidi(&(0x7f0000000000)='/dev/admmidi#\x00', 0x6, 0x8000) setsockopt$SO_VM_SOCKETS_BUFFER_MAX_SIZE(r2, 0x28, 0x2, &(0x7f0000000080)=0xffffffffffffff00, 0x8) [ 359.306427] snd_virmidi snd_virmidi.0: control 112:0:0:�:0 is already present ----------