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Mon, 18 Aug 2025 08:57:59 -0400 X-MC-Unique: g_mIRCGpMROsggNnLgJ-Wg-1 X-Mimecast-MFC-AGG-ID: g_mIRCGpMROsggNnLgJ-Wg_1755521876 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id E3B3018002C2; Mon, 18 Aug 2025 12:57:50 +0000 (UTC) Received: from dhcp-27-174.brq.redhat.com (unknown [10.44.34.24]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with SMTP id 4136D1955F24; Mon, 18 Aug 2025 12:57:43 +0000 (UTC) Received: by dhcp-27-174.brq.redhat.com (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Mon, 18 Aug 2025 14:56:33 +0200 (CEST) Date: Mon, 18 Aug 2025 14:56:26 +0200 From: Oleg Nesterov To: syzbot , David Howells , Dominique Martinet , K Prateek Nayak Cc: akpm@linux-foundation.org, brauner@kernel.org, dvyukov@google.com, elver@google.com, glider@google.com, jack@suse.cz, kasan-dev@googlegroups.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, syzkaller-bugs@googlegroups.com, viro@zeniv.linux.org.uk, willy@infradead.org Subject: Re: [syzbot] [fs?] [mm?] INFO: task hung in v9fs_file_fsync Message-ID: <20250818125625.GC18626@redhat.com> References: <20250818114404.GA18626@redhat.com> <68a31e33.050a0220.e29e5.00a6.GAE@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <68a31e33.050a0220.e29e5.00a6.GAE@google.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 X-Rspamd-Queue-Id: 513DA80010 X-Rspamd-Server: rspam04 X-Rspam-User: X-Stat-Signature: scrpoy118ntiiu8dniqkbyhonhjs1xfp X-HE-Tag: 1755521883-692370 X-HE-Meta: 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 6qH2VWwM 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 08/18, syzbot wrote: > > Hello, > > syzbot has tested the proposed patch and the reproducer did not trigger any issue: > > Reported-by: syzbot+d1b5dace43896bc386c3@syzkaller.appspotmail.com > Tested-by: syzbot+d1b5dace43896bc386c3@syzkaller.appspotmail.com > > Tested on: > > commit: 038d61fd Linux 6.16 And trans_fd.c wasn't changed since 038d61fd... Dominique, David, Perhaps you can reconsider the fix that Prateek and I tried to propose in this thread [syzbot] [netfs?] INFO: task hung in netfs_unbuffered_write_iter https://lore.kernel.org/all/67dedd2f.050a0220.31a16b.003f.GAE@google.com/ Oleg. --- diff --git a/net/9p/trans_fd.c b/net/9p/trans_fd.c index 339ec4e54778..474fe67f72ac 100644 --- a/net/9p/trans_fd.c +++ b/net/9p/trans_fd.c @@ -666,7 +666,6 @@ static void p9_poll_mux(struct p9_conn *m) static int p9_fd_request(struct p9_client *client, struct p9_req_t *req) { - __poll_t n; int err; struct p9_trans_fd *ts = client->trans; struct p9_conn *m = &ts->conn; @@ -686,13 +685,7 @@ static int p9_fd_request(struct p9_client *client, struct p9_req_t *req) list_add_tail(&req->req_list, &m->unsent_req_list); spin_unlock(&m->req_lock); - if (test_and_clear_bit(Wpending, &m->wsched)) - n = EPOLLOUT; - else - n = p9_fd_poll(m->client, NULL, NULL); - - if (n & EPOLLOUT && !test_and_set_bit(Wworksched, &m->wsched)) - schedule_work(&m->wq); + p9_poll_mux(m); return 0; }