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Mon, 18 Aug 2025 09:05:53 -0400 X-MC-Unique: XlWK2UtwMF-ScKJ_-M8afQ-1 X-Mimecast-MFC-AGG-ID: XlWK2UtwMF-ScKJ_-M8afQ_1755522351 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-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 5711A19560AE; Mon, 18 Aug 2025 13:05:45 +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 5D9E6195419F; Mon, 18 Aug 2025 13:05:38 +0000 (UTC) Received: by dhcp-27-174.brq.redhat.com (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Mon, 18 Aug 2025 15:04:28 +0200 (CEST) Date: Mon, 18 Aug 2025 15:04:20 +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, Eric Van Hensbergen , Latchesar Ionkov , v9fs@lists.linux.dev Subject: Re: [syzbot] [fs?] [mm?] INFO: task hung in v9fs_file_fsync Message-ID: <20250818130419.GD18626@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-Server: rspam02 X-Rspamd-Queue-Id: 9D9D5140010 X-Stat-Signature: aor9com5dpohqwq9b6aq6ui4rtnj4j5m X-Rspam-User: X-HE-Tag: 1755522358-122788 X-HE-Meta: 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 2mg432Kq rbqc+NYhQ4lrR6qUNgJQlgYXSHuxpvZYoN9m7h+kYBYRQCwKl8u90A8Bo3HxtUxXvpRl7CZyl8jmn6ffASx1TpRNe6fvz9JoyqGwz9wc7oMU2Zkps5vTxKYmZ+UwSjEG5kvWmoqSQjAwkckF/C7JbA9wqz0VH3f4F47aRGSr6nxdB/1DcnC+iRIE5DjwcLdmEn5XC8jTITahH4pnRjqDVmAWQ2A== 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; }