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 1C61F1BFE00 for ; Fri, 28 Mar 2025 14:50:19 +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=1743173421; cv=none; b=TKshE0UvXF878upu73OK/btKNjf+JumINvpojrq0gAtNz3ORABvh8xgiwsX2qi5RRIecWZUC86BnnJGSCzjPAOUalxaZo0ao1o4YtgI6wjZgNkxy/w/M2OAK45dxAEgq71m+TDLg3BrADgRp0/fVofNW2zXDlPDn5InlezT65VY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743173421; c=relaxed/simple; bh=RpZwkFsJMVj3IgV4ResMHNR65Ry7yNtxeYsBHyLQ+os=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=rmPaekbAUwDGHE6+6anmIwxs/nA3U8cgM3FXRRfOghTQpKsbuIpP8Am9lcDLit52/w3W+NC6jC9l4VRZCcf5gTvaGOGMUzVJOK28+3buFQck/4yjCqPDg7Pf1CXCibB8moc2fj7dWQOJ3yqo/6WgXFM4C32rTxROslLEkj4FJaE= 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=cnBYQ55R; 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="cnBYQ55R" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1743173419; 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=m/9LyAVE5c7oB3rEdELb5gAK+dBdPA0z3HyLPL0kUCo=; b=cnBYQ55RlI26Kc55Z19ImwSy3qfe4VL39BpqxI6m52TctRMS0BlK5zVExKumnq4I/V071W NDH6oJO7C5FK0vWPlREakfuOwBu09uR5soPIkrcq2WcRyOOkiDm60I+WBXknS+jxJz0Iqc 1BPj3PsLbXZ3RbtNrOxh+akBefCTCgo= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-633-hUzKdYtWM92KFOntriwGMQ-1; Fri, 28 Mar 2025 10:50:14 -0400 X-MC-Unique: hUzKdYtWM92KFOntriwGMQ-1 X-Mimecast-MFC-AGG-ID: hUzKdYtWM92KFOntriwGMQ_1743173412 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (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-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 42A451956078; Fri, 28 Mar 2025 14:50:11 +0000 (UTC) Received: from dhcp-27-174.brq.redhat.com (unknown [10.44.33.25]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with SMTP id 0BF671801A6D; Fri, 28 Mar 2025 14:50:03 +0000 (UTC) Received: by dhcp-27-174.brq.redhat.com (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Fri, 28 Mar 2025 15:49:37 +0100 (CET) Date: Fri, 28 Mar 2025 15:49:28 +0100 From: Oleg Nesterov To: syzbot Cc: asmadeus@codewreck.org, brauner@kernel.org, dhowells@redhat.com, ericvh@kernel.org, jack@suse.cz, jlayton@kernel.org, kprateek.nayak@amd.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux_oss@crudebyte.com, lucho@ionkov.net, mjguzik@gmail.com, netfs@lists.linux.dev, swapnil.sapkal@amd.com, syzkaller-bugs@googlegroups.com, v9fs@lists.linux.dev, viro@zeniv.linux.org.uk Subject: Re: [syzbot] [netfs?] INFO: task hung in netfs_unbuffered_write_iter Message-ID: <20250328144928.GC29527@redhat.com> References: <20250328132557.GB29527@redhat.com> <67e6a8ce.050a0220.2f068f.0077.GAE@google.com> Precedence: bulk X-Mailing-List: netfs@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <67e6a8ce.050a0220.2f068f.0077.GAE@google.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 On 03/28, syzbot wrote: > > Hello, > > 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 Looks "obviously unrelated", but I'm not sure about anything anymore. In any case I leave this to 9p maintainers. Okay, just out of curiosity: #syz test: upstream aaec5a95d59615523db03dd53c2052f0a87beea7 diff --git a/net/9p/trans_fd.c b/net/9p/trans_fd.c index 56e62978e502..aa9cd248a243 100644 --- a/net/9p/trans_fd.c +++ b/net/9p/trans_fd.c @@ -669,7 +669,6 @@ 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; struct p9_trans_fd *ts = client->trans; struct p9_conn *m = &ts->conn; @@ -687,13 +686,7 @@ 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; }