From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from NAM11-BN8-obe.outbound.protection.outlook.com (mail-bn8nam11on2041.outbound.protection.outlook.com [40.107.236.41]) (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 E057B189BAC; Tue, 25 Mar 2025 02:52:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=40.107.236.41 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742871165; cv=fail; b=Q9w/bE0xoz72S1tZygZ2X5ITB9E4Z5P7eqCFvxqbxpMZ23th94lWt5eDAMJyicbAAFymDyY2qKN1H871qPuPU+6tlN711eQwwiIrGDZPG1V4zZJWLe7jUq9Wqo45LuqYU1XbuhkKjDW1QuQKba9vUV9HjSX7XQzgb6R2ev1JnbQ= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742871165; c=relaxed/simple; bh=YDgfE39MmNyMz4znYhm4uzGopPmIHJVwEDqWaIc3Zfc=; h=Message-ID:Date:MIME-Version:Subject:From:To:CC:References: In-Reply-To:Content-Type; b=G4oTzf6VtlUzNsrbugokqo9VvSSgQr+dMhwOoX9tt73pMnKMyVzMp1radZfigaivIdP18/2WER2/cKbdnSM6hJj20OM3Ej7DQiWKpIT1ssocQ12kVjgiAQUmQjTreCLNe/T5Szjz67CSR0grNd4hChNPdGB5InyvOxzju4Vw3Cc= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amd.com; spf=fail smtp.mailfrom=amd.com; dkim=pass (1024-bit key) header.d=amd.com header.i=@amd.com header.b=qVr8Untt; arc=fail smtp.client-ip=40.107.236.41 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amd.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=amd.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=amd.com header.i=@amd.com header.b="qVr8Untt" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=JrWL/kVXcmnX4tmwOih+GjJ9fjXcT0LjQcV1xnjq72nQ3DF67pv1ggtXXIgO/inMFHlgtP9y5PwN80hZULqpCdbEOTmA/Sxxn1oyCrrvH+xoBheYpT+/YnIYNGm3QyO06cDt6/uhD/KvoLw5ODWrDXFVi5OaAIvCIg5phTR8KB5lNSBM9XKixyCddZMeoBsyTLisY8NFA60ZU/ORR5zTfq5fVBjQjvrASSg5CB2awVvz3euQg97yTd6xVF3Mtm6g5+SjB2h46jBg8VH0FcA394Gq8Pk5nKTPVD4gSOq0yfJwR/u1/e1btc8Nflc8P8BTTnoJhrvi8d7euiEk4+ZTHQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=vW5lxkmNWf7qVnlEqHNwog4VB0hgVU/jwPGfI2eURjU=; b=tobhTsgC1o2xPYccDZrv0JxuZSuyKO5dygwZF6kfurQG+N/64OdY4Ut4PcDvZFaPnxfC78BQuimsQC7VuBSjo8m4TKlr5Vb1pdlAqRbvhBdWBojBC/V5EMJYZTpQwUhHsgbF2RxFjmfS+sBs59Ck6lIueQZVO9MH8l9hXCaIGgMTls+PdQh7poyqK0W7Pww5ssMUMCki6LL/SY8NjZS1lncyD0MltHZUeXaXQ+Vm1UgUl2nCXWCOetacsE8DUHTbSGNm3U1Fn5sd5zYjP1NfaDmYm+7E+LM9W/yxbE3/CBFtpkpXuI0/EyWyquef8uha0CsiQe1k2+ZifAUs0m2Tsw== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass (sender ip is 165.204.84.17) smtp.rcpttodomain=redhat.com smtp.mailfrom=amd.com; dmarc=pass (p=quarantine sp=quarantine pct=100) action=none header.from=amd.com; dkim=none (message not signed); arc=none (0) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amd.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=vW5lxkmNWf7qVnlEqHNwog4VB0hgVU/jwPGfI2eURjU=; b=qVr8Untt2YSAeb2k+QjOBFLVuszG78wgp0LkwOB6F5qvHBmc5qKzHF7tUDDoU4XUkRhKOIPE63F13n8l0NOd1B9sV1tWAGMy76Ywxg8NHFKobD1Syc2gbB+Uafojr/OWlw4BQwV5Vd+Z9PX8ekI4BTHassqvtyZIwDkirXrzcG8= Received: from SN7PR04CA0003.namprd04.prod.outlook.com (2603:10b6:806:f2::8) by MN6PR12MB8469.namprd12.prod.outlook.com (2603:10b6:208:46e::19) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.8534.42; Tue, 25 Mar 2025 02:52:38 +0000 Received: from SA2PEPF00003F61.namprd04.prod.outlook.com (2603:10b6:806:f2:cafe::1d) by SN7PR04CA0003.outlook.office365.com (2603:10b6:806:f2::8) with Microsoft SMTP Server (version=TLS1_3, cipher=TLS_AES_256_GCM_SHA384) id 15.20.8534.42 via Frontend Transport; Tue, 25 Mar 2025 02:52:38 +0000 X-MS-Exchange-Authentication-Results: spf=pass (sender IP is 165.204.84.17) smtp.mailfrom=amd.com; dkim=none (message not signed) header.d=none;dmarc=pass action=none header.from=amd.com; Received-SPF: Pass (protection.outlook.com: domain of amd.com designates 165.204.84.17 as permitted sender) receiver=protection.outlook.com; client-ip=165.204.84.17; helo=SATLEXMB04.amd.com; pr=C Received: from SATLEXMB04.amd.com (165.204.84.17) by SA2PEPF00003F61.mail.protection.outlook.com (10.167.248.36) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.20.8534.20 via Frontend Transport; Tue, 25 Mar 2025 02:52:38 +0000 Received: from [10.136.45.191] (10.180.168.240) by SATLEXMB04.amd.com (10.181.40.145) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.39; Mon, 24 Mar 2025 21:52:35 -0500 Message-ID: Date: Tue, 25 Mar 2025 08:22:32 +0530 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [syzbot] [netfs?] INFO: task hung in netfs_unbuffered_write_iter From: K Prateek Nayak To: Oleg Nesterov , Mateusz Guzik CC: syzbot , , , , , , , , , , References: <20250323184848.GB14883@redhat.com> <67e05e30.050a0220.21942d.0003.GAE@google.com> <20250323194701.GC14883@redhat.com> <20250323210251.GD14883@redhat.com> <7e377feb-a78b-4055-88cc-2c20f924bf82@amd.com> Content-Language: en-US In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-ClientProxiedBy: SATLEXMB03.amd.com (10.181.40.144) To SATLEXMB04.amd.com (10.181.40.145) X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: SA2PEPF00003F61:EE_|MN6PR12MB8469:EE_ X-MS-Office365-Filtering-Correlation-Id: c9273a7a-2e73-4767-6f94-08dd6b481ab7 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|82310400026|7416014|376014|36860700013|1800799024|13003099007; X-Microsoft-Antispam-Message-Info: =?utf-8?B?S1F6aGt6K2RMa3dXKzlTRG5IdHR3MzhHVytEc3pFUTBxWW9rbGpKR1dwcEsz?= =?utf-8?B?a29SU3FnbWNNeXVOMGNYekdTS0tlbE9mTTNlSlc4Nmt3aGcrNU5VdVN1RkRR?= =?utf-8?B?dzRuazJRU3Q1ZXFaZlhDWTRJYUgrWHRHWnE5ODJOZFBmY0Zyem82M2l1Yzgr?= =?utf-8?B?ZFVTUnhrNS8xcjI2OE02UGhWWXVoc2dlek43b0w5RTlJK1pSdnZtOVRteGNp?= =?utf-8?B?Z1d2cnBNTXVWWHRpa3pibXdVTVB1VkpoQ01PU3hya3BnaUhmcWVGeHYxbVRM?= =?utf-8?B?U3BHUm00d2dzcCtySXFlYUpuNGlWMTJtb2RZSWpoZmJvSlVjVS95cWY2YkRR?= =?utf-8?B?ZUh5U0xKVEVaa3Y1ejk1ek5DRmRtRVZqdis2UE11QWovSVJtRE4rTEU1Rm5Y?= =?utf-8?B?RlRqT21jckZSWDlXREtwdVZJQ1RJa1NkZDJVZ1lKQW5JT3lEUjhiRGJGVTl6?= =?utf-8?B?QnFvL0VOaVlrREgrTHFSSnJoWkwrZGFJcXI4YkVjNXFzWGNsOVYxNGl5Yjc0?= =?utf-8?B?TFFhbDcvKzZSSm9YUGVqeDJvcTE2eWt1RTVjTEZPVTVUYmhLRC9pbTNQU1JN?= =?utf-8?B?V09DVzNvVHhjMWkwV3dZWTdrcDd0TFluUDVaQUJtLytUZ0wwZGl0S293SklM?= =?utf-8?B?WGtoRE9WMWk4ZHhQc2U3TGZaT09IeXh5RnU5M01kTGVoUFl5cmdQZ0hjekpJ?= =?utf-8?B?RUtEdmRuVFpZcktQQjl0TDFVcldPenZnS2VGSXlpTm1SNDlkMEZ0ZmlOVDdU?= =?utf-8?B?NTgrNmpNMEpHZi9ubUpUOGFlMk0xOVdTUlJTdWRuZjE4YnFLWkF6Qk1iZCty?= =?utf-8?B?b2ZnTXlLdmpQVFdUUnBTZGJETFBjWXlCRmdqWTBCRlpIL0lKNjhjcnd4Sjgz?= =?utf-8?B?a3JNM3BXOE1WTlZyUm1EcWsrY2FjK25zcVpOLzBNUVpqRzVUN091MDB0bkJh?= =?utf-8?B?UEJpd0x2M04zMk51Qm1PaGtVcy96akE0WWVnNkFYZnN4eFRHVFB0VlNaSmFi?= =?utf-8?B?dEhMYzkwYVJKNWd4U1dIVkc4TC92VnQxSWU0UVVhMitBZDBSNmx4a2RNODEx?= =?utf-8?B?cVRTVFpHNXdqWW1vVWZhK29ISXl4NHF6L0NWSjZDWkZyS0lENjVJYnNVR1FV?= =?utf-8?B?cTJqTEtaUGxVZ3dhalE4RHVMNGptT25SWEpuK01iMnJRT3JaRHM0Y0lzbndp?= =?utf-8?B?UVRPMmlJelY5cWI4ekdHZ2xra0psWVJHRTR0dDE3bVkwODk3NjF1M1Jlc3px?= =?utf-8?B?WTFnTjIvYXlYZW9PU1dKRm5mdHAyV3FDdmJtUWVBNjFZR0taWDVCSGI5dkFJ?= =?utf-8?B?c29rY0lEb0dKejJlZ24ya2R2eGdoajBZeXFUbFdQbExZaC9JOWhnaGRlaTlY?= =?utf-8?B?MmJ3QldNZnk5Q08ySjVwVEhwMTMrbU92dXJUN0NTZEwrUlNZS1pZdENpaGZ4?= =?utf-8?B?QUhQeWtDYU5Sb2ZyY1E5MDIxY1hLVDRGS2JEaWxDeDlkQVNWL2YzWUZKT1hW?= =?utf-8?B?VHpJRVVZdEJvR0pQMlBWSWxDdFNmSVhnRDhGWUk3d3hJa2toUFlhYXRYOXhi?= =?utf-8?B?TlU0aDRFSXVRdE9nbHNwRG1Qb3RHL21LOEFWazdGTnVoektERE96QmE0c2Ro?= =?utf-8?B?RXZuOWtPTWZ0Vm9nYURmYzlsdDdDTWtWWjVjeGlQajJTandMS1JnMFhtYmVD?= =?utf-8?B?MFladWQ1VEFuR2NMQjZyMU9SQTh6UGloV3U5NFRQZUd5U0dlbFhyRjF2MHE2?= =?utf-8?B?emFBK0t3TkxZMENxUE9KSE9Odi90dGhvaldRL0cyam05aExTeStiZkNCUkdx?= =?utf-8?B?dHZQQWFzSmxmb2w3OS9RTHcrdDRBODNnZE4yS2JDNjNlRUpzSnlPdGVGQjMr?= =?utf-8?B?Tk5NR0hQUkROb29FYUFybUMyN3dTaEFyc3YvM2NkNDVMalhrYVRaaUQ3RE1M?= =?utf-8?B?Ti9FNzcvM2R5NEVJR0VDVk1sWGFZUEl3RGY5L1poSEl6WXN5UU8zNlVldzA4?= =?utf-8?Q?zX3YuOct5qAZN/2UaB+luGg5t6L6/s=3D?= X-Forefront-Antispam-Report: CIP:165.204.84.17;CTRY:US;LANG:en;SCL:1;SRV:;IPV:CAL;SFV:NSPM;H:SATLEXMB04.amd.com;PTR:InfoDomainNonexistent;CAT:NONE;SFS:(13230040)(82310400026)(7416014)(376014)(36860700013)(1800799024)(13003099007);DIR:OUT;SFP:1101; X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 25 Mar 2025 02:52:38.5900 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: c9273a7a-2e73-4767-6f94-08dd6b481ab7 X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d;Ip=[165.204.84.17];Helo=[SATLEXMB04.amd.com] X-MS-Exchange-CrossTenant-AuthSource: SA2PEPF00003F61.namprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: MN6PR12MB8469 On 3/24/2025 8:22 PM, K Prateek Nayak wrote: > Hello folks, > > Some updates. > > On 3/24/2025 6:49 PM, K Prateek Nayak wrote: >>> >>> Per syzbot this attempt did not work out either. >>> >>> I think the blind stabs taken by everyone here are enough. >>> >>> The report does not provide the crucial bit: what are the other >>> threads doing. Presumably someone else is stuck somewhere, possibly >>> not even in pipe code and that stuck thread was supposed to wake up >>> the one which trips over hung task detector. Figuring out what that >>> thread is imo the next step. >>> >>> I failed to find a relevant command in >>> https://github.com/google/syzkaller/blob/master/docs/syzbot.md >>> >>> So if you guys know someone on syzkaller side, maybe you can ask them >>> to tweak the report *or* maybe syzbot can test a "fix" which makes >>> hung task detector also report all backtraces? I don't know if that >>> can work, the output may be long enough that it will get trimmed by >>> something. >>> >>> I don't have to time work on this for now, just throwing ideas. >> >> I got the reproducer running locally. Tracing stuff currently to see >> what is tripping. Will report back once I find something interesting. >> Might take a while since the 9p bits are so far spread out. >> > > So far, with tracing, this is where I'm: > > o Mainline + Oleg's optimization reverted: > >     ... >     kworker/43:1-1723    [043] .....   115.309065: p9_read_work: Data read wait 55 >     kworker/43:1-1723    [043] .....   115.309066: p9_read_work: Data read 55 >     kworker/43:1-1723    [043] .....   115.309067: p9_read_work: Data read wait 7 >     kworker/43:1-1723    [043] .....   115.309068: p9_read_work: Data read 7 >            repro-4138    [043] .....   115.309084: netfs_wake_write_collector: Wake collector >            repro-4138    [043] .....   115.309085: netfs_wake_write_collector: Queuing collector work >            repro-4138    [043] .....   115.309088: netfs_unbuffered_write: netfs_unbuffered_write >            repro-4138    [043] .....   115.309088: netfs_end_issue_write: netfs_end_issue_write >            repro-4138    [043] .....   115.309089: netfs_end_issue_write: Write collector need poke 0 >            repro-4138    [043] .....   115.309091: netfs_unbuffered_write_iter_locked: Waiting on NETFS_RREQ_IN_PROGRESS! >  kworker/u1030:1-1951    [168] .....   115.309096: netfs_wake_write_collector: Wake collector >  kworker/u1030:1-1951    [168] .....   115.309097: netfs_wake_write_collector: Queuing collector work >  kworker/u1030:1-1951    [168] .....   115.309102: netfs_write_collection_worker: Write collect clearing and waking up! >     ... (syzbot reproducer continues) > > o Mainline: > >    kworker/185:1-1767    [185] .....   109.485961: p9_read_work: Data read wait 7 >    kworker/185:1-1767    [185] .....   109.485962: p9_read_work: Data read 7 >    kworker/185:1-1767    [185] .....   109.485962: p9_read_work: Data read wait 55 >    kworker/185:1-1767    [185] .....   109.485963: p9_read_work: Data read 55 >            repro-4038    [185] .....   114.225717: netfs_wake_write_collector: Wake collector >            repro-4038    [185] .....   114.225723: netfs_wake_write_collector: Queuing collector work >            repro-4038    [185] .....   114.225727: netfs_unbuffered_write: netfs_unbuffered_write >            repro-4038    [185] .....   114.225727: netfs_end_issue_write: netfs_end_issue_write >            repro-4038    [185] .....   114.225728: netfs_end_issue_write: Write collector need poke 0 >            repro-4038    [185] .....   114.225728: netfs_unbuffered_write_iter_locked: Waiting on NETFS_RREQ_IN_PROGRESS! >    ... (syzbot reproducer hangs) > > There is a third "kworker/u1030" component that never gets woken up for > reasons currently unknown to me with Oleg's optimization. I'll keep > digging. More data ... I chased this down to p9_client_rpc() net/9p/client.c specifically: err = c->trans_mod->request(c, req); if (err < 0) { /* write won't happen */ p9_req_put(c, req); if (err != -ERESTARTSYS && err != -EFAULT) c->status = Disconnected; goto recalc_sigpending; } c->trans_mod->request() calls p9_fd_request() in net/9p/trans_fd.c which basically does a p9_fd_poll(). Previously, the above would fail with err as -EIO which would cause the client to "Disconnect" and the retry logic would make progress. Now however, the err returned is -ERESTARTSYS which will not cause a disconnect and the retry logic will hang somewhere in p9_client_rpc() later. I'll chase it a little more but if 9p folks can chime in it would be great since I'm out of my depths here. P.S. There are more interactions at play and I'm trying to still piece them together. Relevant traces: o Mainline + Oleg's optimization reverted: repro-4161 [239] ..... 107.785644: p9_client_write: p9_client_rpc done repro-4161 [239] ..... 107.785644: p9_client_write: p9_pdup repro-4161 [239] ..... 107.785644: p9_client_write: iter revert repro-4161 [239] ..... 107.785644: p9_client_write: p9_client_rpc repro-4161 [239] ..... 107.785653: p9_fd_request: p9_fd_request repro-4161 [239] ...1. 107.785653: p9_fd_request: p9_fd_request error repro-4161 [239] ..... 107.785653: p9_client_rpc: Client disconnected (no write) <------------- "write won't happen" case repro-4161 [239] ..... 107.785655: p9_client_write: p9_client_rpc done repro-4161 [239] ..... 107.785655: p9_client_write: p9_client_rpc error (-5) <------------- -EIO repro-4161 [239] ..... 107.785656: v9fs_issue_write: Issue write done 2 err(-5) repro-4161 [239] ..... 107.785657: netfs_write_subrequest_terminated: Collector woken up from netfs_write_subrequest_terminated repro-4161 [239] ..... 107.785657: netfs_wake_write_collector: Wake collector repro-4161 [239] ..... 107.785658: netfs_wake_write_collector: Queuing collector work repro-4161 [239] ..... 107.785660: v9fs_issue_write: Issue write subrequest terminated 2 repro-4161 [239] ..... 107.785661: netfs_unbuffered_write: netfs_unbuffered_write repro-4161 [239] ..... 107.785661: netfs_end_issue_write: netfs_end_issue_write repro-4161 [239] ..... 107.785662: netfs_end_issue_write: Write collector need poke 0 repro-4161 [239] ..... 107.785662: netfs_unbuffered_write_iter_locked: Waiting on NETFS_RREQ_IN_PROGRESS! kworker/u1038:0-1583 [105] ..... 107.785667: netfs_retry_writes: netfs_reissue_write 1 kworker/u1038:0-1583 [105] ..... 107.785668: v9fs_issue_write: v9fs_issue_write kworker/u1038:0-1583 [105] ..... 107.785669: p9_client_write: p9_client_rpc kworker/u1038:0-1583 [105] ..... 107.785669: p9_client_prepare_req: p9_client_prepare_req eio 1 kworker/u1038:0-1583 [105] ..... 107.785670: p9_client_rpc: p9_client_rpc early err return kworker/u1038:0-1583 [105] ..... 107.785670: p9_client_write: p9_client_rpc done kworker/u1038:0-1583 [105] ..... 107.785671: p9_client_write: p9_client_rpc error (-5) kworker/u1038:0-1583 [105] ..... 107.785672: v9fs_issue_write: Issue write done 0 err(-5) kworker/u1038:0-1583 [105] ..... 107.785672: netfs_write_subrequest_terminated: Collector woken up kworker/u1038:0-1583 [105] ..... 107.785672: netfs_wake_write_collector: Wake collector kworker/u1038:0-1583 [105] ..... 107.785672: netfs_wake_write_collector: Queuing collector work kworker/u1038:0-1583 [105] ..... 107.785677: v9fs_issue_write: Issue write subrequest terminated 0 kworker/u1038:0-1583 [105] ..... 107.785684: netfs_write_collection_worker: Write collect clearing and waking up! repro-4161 [239] ..... 107.785883: p9_client_prepare_req: p9_client_prepare_req eio 1 ... (continues) o Mainline: repro-4161 [087] ..... 123.474660: p9_client_write: p9_client_rpc done repro-4161 [087] ..... 123.474661: p9_client_write: p9_pdup repro-4161 [087] ..... 123.474661: p9_client_write: iter revert repro-4161 [087] ..... 123.474661: p9_client_write: p9_client_rpc repro-4161 [087] ..... 123.474672: p9_fd_request: p9_fd_request repro-4161 [087] ..... 123.474673: p9_fd_request: p9_fd_request EPOLL repro-4161 [087] ..... 123.474673: p9_fd_poll: p9_fd_poll rd poll repro-4161 [087] ..... 123.474674: p9_fd_poll: p9_fd_request wr poll repro-4161 [087] ..... 128.233025: p9_client_write: p9_client_rpc done repro-4161 [087] ..... 128.233033: p9_client_write: p9_client_rpc error (-512) <------------- -ERESTARTSYS repro-4161 [087] ..... 128.233034: v9fs_issue_write: Issue write done 2 err(-512) repro-4161 [087] ..... 128.233035: netfs_write_subrequest_terminated: Collector woken repro-4161 [087] ..... 128.233036: netfs_wake_write_collector: Wake collector repro-4161 [087] ..... 128.233036: netfs_wake_write_collector: Queuing collector work repro-4161 [087] ..... 128.233040: v9fs_issue_write: Issue write subrequest terminated 2 repro-4161 [087] ..... 128.233040: netfs_unbuffered_write: netfs_unbuffered_write repro-4161 [087] ..... 128.233040: netfs_end_issue_write: netfs_end_issue_write repro-4161 [087] ..... 128.233041: netfs_end_issue_write: Write collector need poke 0 repro-4161 [087] ..... 128.233041: netfs_unbuffered_write_iter_locked: Waiting on NETFS_RREQ_IN_PROGRESS! kworker/u1035:0-1580 [080] ..... 128.233077: netfs_retry_writes: netfs_reissue_write 1 kworker/u1035:0-1580 [080] ..... 128.233078: v9fs_issue_write: v9fs_issue_write kworker/u1035:0-1580 [080] ..... 128.233079: p9_client_write: p9_client_rpc kworker/u1035:0-1580 [080] ..... 128.233099: p9_fd_request: p9_fd_request kworker/u1035:0-1580 [080] ..... 128.233101: p9_fd_request: p9_fd_request EPOLL kworker/u1035:0-1580 [080] ..... 128.233101: p9_fd_poll: p9_fd_poll rd poll kworker/u1035:0-1580 [080] ..... 128.233101: p9_fd_poll: p9_fd_request wr poll (Hangs) -- Thanks and Regards, Prateek