From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 3875731E0E5 for ; Mon, 18 Aug 2025 13:05:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755522359; cv=none; b=gwn+rdVxy8ZLY/vy+mfSw227sgBoVgEZ3IapyNT+nyRjaxoEjQXXqCBR8vSlGYrx4vIEN3UVAwHZ73lx9s2Vfa95/YCRowovgJDahzZuP/6qth8WXq0Xp6VmyvZWn5fD06W25tBTz4DafwRY4NIZ7xpvjALXqEbp7eDs6zZ30BM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755522359; 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=a4Wzfc0i+tXZCM+J1cG9ylpWdev/Gzkh+qVKOwo8vXQF6bzgqvBS9dr2L9fpae65T5uPMlR/T+/7p0m04ZGzDnAT7dMQ85cAZcmcyQo2tVYoLmBfMbgHo5w3nVE45beGnBujVIHlzw54YCSWWFU0U0Mvm0b6W7phAn+YMtX0PxM= 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=HgZ+5spS; arc=none smtp.client-ip=170.10.133.124 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="HgZ+5spS" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1755522357; 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=HgZ+5spS1vvwD3gHj5CuwmCbtATeGIRkvq8Oq7oArKfDWpMOoaM1nRmW4C0b50c81XF5KW j2UPjepysUWci+TEPMiA0Sunss2dpQvIk6VbS9ZM6Ch3euAfm/HUhBjN5yDIFerQ42iYLm nruurFqPt7qNt/MMtJiXIuCtVLwvLic= Received: from mx-prod-mc-02.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-284-XlWK2UtwMF-ScKJ_-M8afQ-1; 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> Precedence: bulk X-Mailing-List: linux-fsdevel@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; }