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client-ip=165.204.84.17; helo=SATLEXMB04.amd.com; pr=C Received: from SATLEXMB04.amd.com (165.204.84.17) by SJ5PEPF000001CF.mail.protection.outlook.com (10.167.242.43) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.20.8534.20 via Frontend Transport; Fri, 28 Mar 2025 17:56:32 +0000 Received: from [10.252.205.52] (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; Fri, 28 Mar 2025 12:56:27 -0500 Message-ID: <314522ae-05a4-4dfb-af99-6bb3901a5522@amd.com> Date: Fri, 28 Mar 2025 23:26:20 +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 To: Oleg Nesterov , syzbot CC: , , , , , , , , , , , , , , , References: <20250328144928.GC29527@redhat.com> <67e6be9a.050a0220.2f068f.007f.GAE@google.com> <20250328170011.GD29527@redhat.com> Content-Language: en-US From: K Prateek Nayak In-Reply-To: <20250328170011.GD29527@redhat.com> Content-Type: text/plain; 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X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 28 Mar 2025 17:56:32.8057 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 7d475756-4036-4acb-2e15-08dd6e21e01d 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: SJ5PEPF000001CF.namprd05.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: SJ2PR12MB8807 Hello Oleg, On 3/28/2025 10:30 PM, Oleg Nesterov wrote: > Dear syzbot, > > On 03/28, syzbot wrote: >> >> syzbot has tested the proposed patch and the reproducer did not trigger any issue: >> >> Reported-by: syzbot+62262fdc0e01d99573fc@syzkaller.appspotmail.com >> Tested-by: syzbot+62262fdc0e01d99573fc@syzkaller.appspotmail.com > Yours is the right approach. I was searching for p9_poll_mux() which would wake the read collector to free pipe buffers but I didn't dig enough and I was too lazy to open code it (guilty!) If this gets picked, feel free to add: Reviewed-and-tested-by: K Prateek Nayak > Thanks. so the previous > > syzbot has tested the proposed patch but the reproducer is still triggering an issue: > unregister_netdevice: waiting for DEV to become free > > unregister_netdevice: waiting for batadv0 to become free. Usage count = 3 > > report suggests that upstream/master has another/unrelated issue(s). I could not reproduce this bit on mainline at commit acb4f33713b9 ("Merge tag 'm68knommu-for-v6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/gerg/m68knommu") so I too second that it is an unrelated issue. > > As for the patches from me or Prateek (thanks again!), I think that > the maintainers should take a look. > > But at this point I am mostly confident that the bisected commit aaec5a95d5961 > ("pipe_read: don't wake up the writer if the pipe is still full") is innocent, > it just reveals yet another problem. > > I guess (I hope ;) Prateek agrees. I agree aaec5a95d5961 is not guilty! (unlike me) :) > > Oleg. > -- Thanks and Regards, Prateek