From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 B3A9B3218CF for ; Mon, 18 Aug 2025 12:58:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755521885; cv=none; b=gzkDoLI/Z8h0AhnLHdivPItE+YqS33yj3eFtQu8M6wMjoYrWSWGJXCbwqKFBZtoRI/hM5ig2R2Mi3BqtmEKQ4pDy/r94z4r3Om4F8prtzq6hJ7U2LT+/QHr0trj+kPkLUBeWoT45g3Em14Gvm+PB4g0lx8AW3F8Mv3WflkcvlVk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755521885; c=relaxed/simple; bh=LVJlZcHzGYt9RgpmISld6bzB/0duxLzZuYmGksm7/2M=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=TiNgdjAXs58kCV+35IGFu5c5HZJK1PYu2IhS4Uf4a0fLeHkkRrvismUaOvVZpZ8B/hH0BjLYUqDHAv5ZUVwNalQ3ov6H3ySevqq2LH4orxSIR8vLz64U3LNSLPZ03Q/mjBodA2syAes5L4bLqTRaiy6xT0fPHIQ+Ce6tzN4p9hs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=gcy8JlzU; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="gcy8JlzU" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1755521882; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=QyzL3GSkiAQfeG6g6YvIMRozhZr0+dfb72trcSazY0Y=; b=gcy8JlzUKImnzwjFGUEg6rKMy8YD8k2iFbh06Iryo8bnTU0qY2bO+fnyr8R3klpfT8t08q Gd0JyIR9ZNSvRoODbWl0aSeyzQy9pm6tmaxarLfOERPfCq9CSGOh5rySJW6j+Tq/CfYMkX GWEMXxMj7YdaZHqaVj+SkLFqAn7w5kE= Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-621-g_mIRCGpMROsggNnLgJ-Wg-1; 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> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: 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 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; }