From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932486AbcHISsh (ORCPT ); Tue, 9 Aug 2016 14:48:37 -0400 Received: from mail-co1nam03on0048.outbound.protection.outlook.com ([104.47.40.48]:47552 "EHLO NAM03-CO1-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S932207AbcHISse (ORCPT ); Tue, 9 Aug 2016 14:48:34 -0400 Authentication-Results: spf=pass (sender IP is 63.163.107.225) smtp.mailfrom=sandisk.com; redhat.com; dkim=none (message not signed) header.d=none;redhat.com; dmarc=bestguesspass action=none header.from=sandisk.com; X-AuditID: ac160c71-eb3ff70000000e72-86-57aa23ec3ac7 Subject: Re: [PATCH] sched: Avoid that __wait_on_bit_lock() hangs To: Oleg Nesterov References: <20160803181128.GH6879@twins.programming.kicks-ass.net> <11007730-3fa5-139a-8091-655743894ae8@sandisk.com> <20160803213006.GA11712@redhat.com> <17b65ff9-215f-ab74-9f5f-15dbd308d054@sandisk.com> <20160804140938.GB24652@twins.programming.kicks-ass.net> <16207b90-2e6c-fe23-1b4b-3763e5cf0384@sandisk.com> <20160808102213.GA6879@twins.programming.kicks-ass.net> <4091e252-18d9-1795-de63-9fbc678aa6b1@acm.org> <20160808162038.GA25927@redhat.com> <78fafdc1-d4ae-a9a2-169c-1d456b6e6e41@sandisk.com> <20160809171459.GA13840@redhat.com> CC: Peter Zijlstra , "mingo@kernel.org" , Andrew Morton , "Johannes Weiner" , Neil Brown , Michael Shaver , "linux-kernel@vger.kernel.org" From: Bart Van Assche Message-ID: <3cec7657-caa9-92ca-9f0e-34f073a6ed8c@sandisk.com> Date: Tue, 9 Aug 2016 11:48:27 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.2 MIME-Version: 1.0 In-Reply-To: <20160809171459.GA13840@redhat.com> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFprAIsWRmVeSWpSXmKPExsWyRoxnke5b5VXhBku/sVvMWb+GzWL1Jl+L NZMesllc3jUHyPt3itFi7/wGFout+1sZLY73HmBy4PA4/OY9s8fOWXfZPTav0PLYtKqTzePE jN8sHu/3XWXz2Hy62uPzJrkAjigum5TUnMyy1CJ9uwSujL0v3jAXnJKtaH4/k62BcaNkFyMn h4SAicTtGd2sILaQwFImiUlNjl2MXED2dkaJlq3HGWGK3h5dywyRWMoosWrPJrAOYQFHia37 PzOD2CICyhJ/7i2AKlrPInFryVMwh1lgJZPEs/sTwTrYBIwkvr2fydLFyM7BK2An8V8eJMoi oCJxqPsKE4gtKhAmMe3uW3YQm1dAUOLkzCdA1RwcnAIGEsc3BYOYzAKaEut36YNUMAvIS2x/ OwdskYTAQ1aJZfenskE8oy5xcsl8pgmMwrOQTJqF0D4LSfsCRuZVjGK5mTnFuempBYYmesWJ eSmZxdl6yfm5mxgh8VS4g/H1be9DjAIcjEo8vBuYVoULsSaWFVfmHmKU4GBWEuFdqwgU4k1J rKxKLcqPLyrNSS0+xCjNwaIkznsx+mOYkEB6YklqdmpqQWoRTJaJg1OqgXHtmafdzV8KV7zf uDF29pX2E8f3fA1j8I22miFffuFnqEgN05G0OaliO1T3xbZNOfmjo++TkZX7bIvz/geeSrhX lT8S5Kw6cHaG4kl5HZcPD5/MnlR/teKZ6PTzb0u9Csou7ZXWW10mGKSW2MH1L7I07r18uNxa PYMTP9nlj9ndiZ/7qOhZsIUSS3FGoqEWc1FxIgD9SedSowIAAA== X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFupgluLIzCtJLcpLzFFi42Lh2siRoluruirc4NR/bos569ewWaze5Gux ZtJDNovLu+YAef9OMVrsnd/AYrF1fyujxfHeA0wOHB6H37xn9tg56y67x+YVWh6bVnWyeZyY 8ZvF4/2+q2wem09Xe3zeJBfAEcVlk5Kak1mWWqRvl8CVsffFG+aCU7IVze9nsjUwbpTsYuTk kBAwkXh7dC1zFyMXh5DAYkaJJ7+mMIMkhAUcJbbu/wxmiwgoS/y5twCqaD2LxK0lT8EcZoGV TBI37/cygVSxCRhJfHs/k6WLkZ2DV8BO4r88SJRFQEXiUPcVsApRgTCJaXffsoPYvAKCEidn PgGq5uDgFDCQOL4pGCTMLKAu8WfeJWYIW15i+9s5zBMY+WYh6ZiFpGwWkrIFjMyrGMVyM3OK c9MzCwwN9YoT81Iyi7P1kvNzNzGCw5ozcgfj04nmhxiZODilGhj155/8c03qmuZx97cxdpM5 G3ecVbi7cXmD4VPnawp64ord/BsY9dIT41s84g5nJ+hsU5HpWGMm7+p5Our2yshV3Bqvpp2W uiny2lPHf1H5uq/RcxL9mR/NNdsY6d/EtsXInav9wOrevjjOfg/XNTKRiRbntmbcay6v73x/ 6t0C3YBbxrd1mZVYijMSDbWYi4oTATSXQ8IbAgAA X-EOPAttributedMessage: 0 X-MS-Office365-Filtering-HT: Tenant X-Forefront-Antispam-Report: CIP:63.163.107.225;IPV:NLI;CTRY:US;EFV:NLI;SFV:NSPM;SFS:(10009020)(6009001)(7916002)(2980300002)(438002)(377454003)(199003)(24454002)(189002)(23676002)(4326007)(93886004)(92566002)(586003)(11100500001)(64126003)(50466002)(86362001)(69596002)(106466001)(83506001)(31696002)(68736007)(65806001)(47776003)(65956001)(81166006)(7696003)(8676002)(2950100001)(31686004)(2906002)(36756003)(110136002)(7846002)(230700001)(87936001)(77096005)(189998001)(50986999)(54356999)(4001350100001)(53416004)(76176999)(97736004)(81156014)(356003)(8936002)(2270400002)(33646002)(305945005)(65826006);DIR:OUT;SFP:1101;SCL:1;SRVR:BN1PR0201MB0545;H:milsmgep14.sandisk.com;FPR:;SPF:Pass;PTR:InfoDomainNonexistent;A:1;MX:1;LANG:en; X-Microsoft-Exchange-Diagnostics: 1;BN1AFFO11FD005;1:xgfW6kxy7PeS4b/9Ir42ZmLbI72hha65T5f5gbNk8jw9hFg6/j8ZrdX6XpeaQHNr9hheD+G9QD4kwkojzX+0u8Ui6LyiJoB6A6g+UyZmroiSq55rpp6gu4I26Fjky4wZ61ykzHGvVWwgfXE4DTQSfa7z+EgK5IhcQ7NINVQ+nn7NHpn8glwfi4Uf7Xb+dALwT2JqQwcC8jWrjhOqG1vqhaae3iz/eOqMhjhHaEErjPgIEu3HwPdKrNuWrYybOYJvHJUd+KKOSSIz00SdqA+t/6oSBDyIDaC3QuGuXoeZTfwUGvSt+K7oogPOXIwtvsDUKq27PtbjovtiJzLuMrnD5PEu6FclTgvmW21hJizcKqpxdv4fD9oDbUpG9brf3xr/q+OdpKbcch00YRj9V00/jEdQGnUSpqDm++8Y2zx3Uog+pIzBirOsb9j4oqwTdOTYLI2ET2N2q72magmAtDowiYeDj1//FWeLdCkvG4fOsZQ= X-MS-Office365-Filtering-Correlation-Id: 8d7dfab1-2ba4-4442-2873-08d3c085c23a X-Microsoft-Exchange-Diagnostics: 1;BN1PR0201MB0545;2:RIjM8Zm9eponcyzPafNZWK5tRD58bufUZMgoeCgxEM4w45/RinhooMhCTnXKQij1xPPvjvEJh3yoE23Dhvi32F/6l/AyyBA2r6D9BXlGOYPXP3gPNPIRrzWhQi3M3VxuxHbby6oOlISXnTbgLbVBULOMh42mYQ2IRvtlSQOXV6fZvBCdXlGAJrfsMNPayfJg;3:qpYaiU8sdGvs0/lpnk1GgtxL0zPOVpkNblNUV40UUdASlP1r2gsrqdAwN37kP03uBn4A0Cpg601Doh29f3ruZFTcQ8z6221BlZU3GH2jXhvBUddEGeEuUFFAE/hKCautvvwXEox0JUB5Kj2NrCr7tfMmVNT/wXn3hnb2ZSFGflVJmzVB5wIgyty8Tm0NuwnBgp+WJPy2a2k4i9FhpqNXgFXE36vGPBBnwlEiVeO2YBfyIDBRyZjPo98cYrdIr8Bb7mR+9VHImXhI8uZ1pvDKIQ==;25:+6bYoSYwYhwu2/PknTDIJ2PxAp1xtRGMh4rV4tISInXDbAGnMPY1IVH2/aNfEsRILoW+DwDsRnW+VsrmUqjeT1V+3h7q1m3kDvYjO+of2jQZoLYh4VYJnJ14acD82KpKIWUNjOSAYYHLCtphhY8k4u2hFBXvEjPRXAON4Xc6f3lcpk+njn5JkTLUc0ULineMgjFA0Tyt0oyv5oQObnuuM/Dr8ck2i2TCjfQuW3hHm6Uhr4SkgBw/krKY+tgtF7vzkzQFaPtJnAQOi/oJ3YUto0swyD5o7fVZkj4X06ErUdHwR4czJeAy38OwPCXUVOqwaQN6gSbFWkHfeeoL6dkHw8lt83jrxMCtL64shmESG/W3Hu6rtLmzu6TDzp7pASQj9n929+Y9VrgLuj33+l2uNqYtGQkEj7Sbc8F+S9CMpZw= X-Microsoft-Antispam: UriScan:;BCL:0;PCL:0;RULEID:(8251501002);SRVR:BN1PR0201MB0545; X-Microsoft-Exchange-Diagnostics: 1;BN1PR0201MB0545;31:JrOd4NbcR+AYrHN7DylCs3HU5BCdaxb5bgr7PprKuc9/R6cPSs8nygH8PV066Mx4JoFyx9pYmjof0AKdsffxmHoPN9fna3Vubl54xjHwdQMRJZtfYY+xY4w6WMD4+VpGIhDsj5ySfEUb+XYt/dcIWY2QIFRrQmLb0fFCY/v5T3ZtK9/M0i4q82TkEH1ZS2DH5ogbYRLdXnRsusWo6yDYpua3KbImjarHY0H/SZbK4N8=;20: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 X-Microsoft-Antispam-PRVS: X-Exchange-Antispam-Report-Test: UriScan:(158342451672863); X-Exchange-Antispam-Report-CFA-Test: BCL:0;PCL:0;RULEID:(601004)(2401047)(13018025)(13016025)(8121501046)(5005006)(10201501046)(3002001)(6055026);SRVR:BN1PR0201MB0545;BCL:0;PCL:0;RULEID:;SRVR:BN1PR0201MB0545; X-Microsoft-Exchange-Diagnostics: 1;BN1PR0201MB0545;4:bB5/b0p4d3kC6JEYg/jsw3NCfe+QbhC5kaFG12KFLJp1STcp/EzYH3uJCE4ZSdx+gPqYu9UFPnW/Z6XJ3Oz4eHow4RkgxiwhorZtdKnbvzMr2k0FoTy2RfkJZkCUyJWnvfAprRuTolPas6go2N66uTRPiycEiMAPrZmNXtBKZXX1cUBzpFhYN22FTrZO7yEpG7N4bzyq7vv8vghiaHO7kKL6hz9IcOBzglUWPVVfYeZ4mYeMDidDri9bp9TrNpL/8SeelK+rGjynvjirCEEtbLFK7UiwwvK41Bx5bkZHELiDyt4evbTFA3oEyNWurWoEaQjzaWDlfhe6rMW/6Cldharje/LSfJP7pUFd3LVNqgLK4X7FH4wY4hN08+OUoAnp0/rv2P200FTUPaakf6Jtyr2D/4wOBv5VAxOpPTebuiMfy+NtaMxe5CE1W2t39iuxctM58y2mgi8W3ZkwDjuGfKtOJKaTO1kLAUnJhZTqGjg= X-Forefront-PRVS: 0029F17A3F X-Microsoft-Exchange-Diagnostics: =?utf-8?B?MTtCTjFQUjAyMDFNQjA1NDU7MjM6MWVTQVB3VXllWExxQXFtNjNXaU15ZjA4?= =?utf-8?B?WUh2bVR4QmhXUjVGUUU0b1ZzNVM0VDB3VnYveTdNeEJPcmtRZVVIYnNnU3k5?= =?utf-8?B?NkRVaHk3S3BvTmV5Z0FpUFQ1L0MrWkswSFc5cTJyaWVOY3RzaDZvL1E5NUcw?= =?utf-8?B?Q2tkZXRGTXFCTHVJYUZ0YXZBZmsxenhCT2lHdXg4UnBlc1kyckNZanBPQnYy?= =?utf-8?B?N2pXOUd6clg4ejZRaGhWQ3hpbG1rbFczQUZ4TXU2ZzI3RTd6cGthaUhjZ2ty?= =?utf-8?B?aVFGRlp3R2kvTFVKNHdHNHFhbWlkaERXb29qc3dKSXpWbzNqb0ZxZCtFbkdT?= =?utf-8?B?UUZxZ2RVN24vN3BXcVdIRmJVNVlUNUVWYXlCK0VhNnVudDBKYTlRaWRCNVpx?= =?utf-8?B?dzFrem9UUURQRnZ3aWJjV0taV2VjcGtja3ZidWRFbGtuS0c3VzhHbkVyMjFa?= =?utf-8?B?K2svOFpxOGhqMjQ1N1YrdjNDRHdlakpGM2pJamZlajdwQUVIc1g2OHRJKzlO?= =?utf-8?B?bUsySGdFQy9XR3RpaWdrNEMwUWJSNDhQTDJ2NmlRNWhvYmNaaHFWNFZySndh?= =?utf-8?B?UXRiM05LZHkyMlc1KzhHRXp5SlJTekVVUTdXVENaZFlEazR3R21hdWw2dmtq?= =?utf-8?B?SEovcXRJZk5oai9ucTVVSGwvdGY5YUdyRG4yNVNyVWVXa3pyY0VhRTZ5enkz?= =?utf-8?B?TGE2T2RybUltNHQ4Tm5UWGZuaC81MGliT1JEQUpkUG81RWYvdnNPa3h5bmJz?= =?utf-8?B?K0IyVGF2VS9ITzcwYUMwbE5GVjlvd3d4ZVZmKzVIaXhqUGV3bnlUM1p5MnJC?= =?utf-8?B?dXdmZEhWSnFRTSt3bkI0YkVHRjZRYkh2a3p4OTh3WnJudTBpNktxbG1OV0Zj?= =?utf-8?B?b2w1b252Y1p3QnlRWmc2QzNaRjZHUk5ObXErTlErcjVGQ2tCU2ZjTjFiT05Z?= =?utf-8?B?K2RFNWtsMFVNU3lxdk5CcUFlNzhFajYzd0ZxUDBseG4zUWpXV1F3R0JlSlZM?= =?utf-8?B?MGNKVEkwQmRHcjVvTVlwVlA4dzFwczJocC84TktZMnVKUE5lRjMwb2xtQUIr?= =?utf-8?B?Rm9Xc0JvaFFBVVFxYzJGM3p2N3RMTTBpVUVHTVlFTkFmazR5RVdKV3JyZVNP?= =?utf-8?B?ak91aTFWams0cTdXbndnUjZOdUZKSTZtMmNPWk9Mc3EzZllWdTFPRWJFR1Z0?= =?utf-8?B?RUg2RTFYRlZLUjBuRmJTMWp2WkJBa0J0WC9qdTRTMG4yNndBSUx6R1NMM1Na?= =?utf-8?B?N2MwLzVjcmhUSlNOSjZpR3Q5bXIxZWdlajk4MzN3L245ajMyeVdNclNjbnlu?= =?utf-8?B?Ky9lUDRYU054Z1hZYjV5RnJ1VFRaT0krS0RLMC8vRlF1VEwweFlIcTF4NWNk?= =?utf-8?B?SmwyUlJFUHRjNGdyV09OM0ZqQnhrRUFTaXlvdThSNnNsa1B3NDI3Q2RCeHFZ?= =?utf-8?B?RDk2MzNxN0RFQ290WWhRVUhrMWhsK2N3NTcrWVU1WGxKUjM1bDRqOVFXdFp4?= =?utf-8?B?c2UrbXg4c1IrRXdYeUoyb3M3YVpTQkdJSWhreWhlOW0vaEkydURQTmM0b1d0?= =?utf-8?B?MHVBVTBtbm9ZaFd3OEU1OUJFS0pYQkdPWVBhSFIxdFZoR1M4RXV1UlByMmkr?= =?utf-8?Q?RjwWewqoDj4UbhEtqvz0EQ?= X-Microsoft-Exchange-Diagnostics: 1;BN1PR0201MB0545;6:mzw1umlC94Bm/bVRKLGGywmKGVFfg8cucQENYpTpVmQRdB4f+Y25ZvPhpR8LXGLFCYRSRv1yvFASvH9F86B7hN+lMS7sTd5UR4g5LcNFiioyu6COfKRhiCpLZb2IRiAz6mQAXn+RWP0brTDnXhHlXtgEV/P+2LGqiepD6EQkEIEuSawVE/vyPq/OM2TF0lJYZUTMHSVxYtsLr0gr3xpn2SAnlFGlpKebUXfJXj6tu5kNGrTSsgsz/pzVF6NGF2tlOokzSgNOe0y/qhVG1peiDPTGS+Jb+yT+XYtRmHG296Jp/z4O0bqSM7+fwUTIESVBjdZiWz2lJapcOExiIxiWFw==;5:bGNIxvPjNtL6Tz1G2ubPMWY4axQnQ8Od/LasV4x6tjwbYiU70iwaSSpBEjSV9J0b99Eou2AJYvvQeBRNwPVESWHqZlqmSA/Xw7W9xrVqHxitYC0AjkwA8qH9+6nsmlKUNuriVm2PY7WuAaXy3Uqt7w==;24:fBJYz1Vco+MlXG0bhTic21iHs/GI7TztkfwhgmM3ByILeR34pBaANAnRJMZeY0349iCOzJvVFj/uw+2YiISuRyugdvLnHmE34GBh+ASyYVk=;7:CNzgtrxS3KQV7IWAZfCxPqlTVrGhZqjbI6ILDqlnZ/F3oR650mac4w/lYN+KNmIL3bSkid26S1/KQ4Hr3mI5jRAaoaPOWFRZ82FiiGCriWAOkU+U+7wma+jBaxxQCl5HlVMNqZ3H3W+rpn4MP8WKcB7RH5fRsq2abYXIQ1rfs0zLzCgBxMgoEQ5nJUkz+LWgklOA+l/1/m14tk/Ey2yxpWyHi/aQ/Uda/qsrz7trAN0sUEgTL8XiCLUW29gGGvL+ SpamDiagnosticOutput: 1:99 SpamDiagnosticMetadata: NSPM X-Microsoft-Exchange-Diagnostics: 1;BN1PR0201MB0545;20:myxkhnsw9Fl4FciXzvvGLfBo///83GzZ1R81YTuv078bMbSmt9jL4NqQpAvNpEWWNmRTXedNXT0cJXehGJB+1xP+8Rsmxl+0+JM9BcYIRc20HPMZXrt0og0tVCK9d1v7KbJ+4uF9EKVFJzEWBgrgu9uvD8Lej6zFpqGpZ/xxUxKMCLn7AvN6EbWKUt0BQoCFDSmfbWUidiVSpEzKVakcup+DuZA3wlmvbWX1fHhkaNBZLmymnSnz0BYIE2gUR72u X-OriginatorOrg: sandisk.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 09 Aug 2016 18:48:30.4126 (UTC) X-MS-Exchange-CrossTenant-Id: fcd9ea9c-ae8c-460c-ab3c-3db42d7ac64d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=fcd9ea9c-ae8c-460c-ab3c-3db42d7ac64d;Ip=[63.163.107.225];Helo=[milsmgep14.sandisk.com] X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: BN1PR0201MB0545 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/09/2016 10:15 AM, Oleg Nesterov wrote: > On 08/08, Bart Van Assche wrote: >> >> No external modules were loaded when I triggered the lockup > > Heh. Could you test the patch below? > > Oleg. > > --- x/kernel/sched/wait.c > +++ x/kernel/sched/wait.c > @@ -283,7 +283,7 @@ void abort_exclusive_wait(wait_queue_hea > if (!list_empty(&wait->task_list)) > list_del_init(&wait->task_list); > else if (waitqueue_active(q)) > - __wake_up_locked_key(q, mode, key); > + __wake_up_locked_key(q, TASK_NORMAL, key); > spin_unlock_irqrestore(&q->lock, flags); > } > EXPORT_SYMBOL(abort_exclusive_wait); Hello Oleg, That patch looks interesting to me. Unfortunately even with that patch applied I still see lockups. These are the two lockups I have observed after I had applied your patch, rebuilt and reinstalled the kernel and rebooted the test server: [ 1548.018115] sysrq: SysRq : Show Blocked State [ 1548.018210] task PC stack pid father [ 1548.018677] systemd-udevd D ffff8803a9f13be8 0 29908 483 0x00000000 [ 1548.018792] ffff8803a9f13be8 ffffffff82584bd0 00ffffff8252b1b0 ffff88046f0569c0 [ 1548.018961] ffff88016c98b140 ffff8800757bc9c0 ffff8803a9f14000 ffff88046f0569c0 [ 1548.019131] 7fffffffffffffff ffffffff8161fcf0 ffff8803a9f13d50 ffff8803a9f13c00 [ 1548.019316] Call Trace: [ 1548.019415] [] schedule+0x37/0x90 [ 1548.019464] [] schedule_timeout+0x27f/0x470 [ 1548.019758] [] io_schedule_timeout+0x9f/0x110 [ 1548.019808] [] bit_wait_io+0x16/0x60 [ 1548.019856] [] __wait_on_bit+0x56/0x80 [ 1548.019906] [] wait_on_page_bit_killable+0xbd/0xc0 [ 1548.020006] [] generic_file_read_iter+0x130/0x770 [ 1548.020158] [] blkdev_read_iter+0x30/0x40 [ 1548.020209] [] __vfs_read+0xbb/0x130 [ 1548.020258] [] vfs_read+0x91/0x130 [ 1548.020305] [] SyS_read+0x44/0xa0 [ 1548.020354] [] entry_SYSCALL_64_fastpath+0x18/0xa8 [ 1050.892823] sysrq: SysRq : Show Blocked State [ 1050.892912] task PC stack pid father [ 1050.893333] systemd-udevd D ffff880449b3f838 0 17240 492 0x00000006 [ 1050.893974] Call Trace: [ 1050.894119] [] schedule+0x37/0x90 [ 1050.894168] [] schedule_timeout+0x27f/0x470 [ 1050.894561] [] io_schedule_timeout+0x9f/0x110 [ 1050.894609] [] bit_wait_io+0x16/0x60 [ 1050.894657] [] __wait_on_bit_lock+0x49/0xa0 [ 1050.894705] [] __lock_page+0xb9/0xc0 [ 1050.894802] [] truncate_inode_pages_range+0x3e0/0x760 [ 1050.895750] [] truncate_inode_pages+0x10/0x20 [ 1050.895799] [] kill_bdev+0x30/0x40 [ 1050.895849] [] __blkdev_put+0x71/0x360 [ 1050.895951] [] blkdev_put+0x49/0x170 [ 1050.895998] [] blkdev_close+0x20/0x30 [ 1050.896047] [] __fput+0xe8/0x1f0 [ 1050.896094] [] ____fput+0x9/0x10 [ 1050.896141] [] task_work_run+0x83/0xb0 [ 1050.896189] [] do_exit+0x3ee/0xc40 [ 1050.896284] [] do_group_exit+0x4b/0xc0 [ 1050.896331] [] get_signal+0x2ca/0x940 [ 1050.896425] [] do_signal+0x23/0x660 [ 1050.896626] [] exit_to_usermode_loop+0x73/0xb0 [ 1050.896678] [] syscall_return_slowpath+0xb0/0xc0 [ 1050.896727] [] entry_SYSCALL_64_fastpath+0xa6/0xa8 Bart.