From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from r3-17.sinamail.sina.com.cn (r3-17.sinamail.sina.com.cn [202.108.3.17]) (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 2F5692737EB for ; Fri, 19 Sep 2025 02:19:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=202.108.3.17 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758248356; cv=none; b=XOWmoNBzE0mAKSjRFImQgqLBQ/l3a5niOl3xHWoTETTG8XELkFcPqR8BT8/n9ezBzxQTubPiY8z/0T1EbhRGMJPOCUmEsiSM2ayUhBEtG2u/BrO5CUzt7Rx2dPRUwEFXw3n43k5xrO48eS7p7Q/ywVjinEskL+7TXopPxlbbbuI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758248356; c=relaxed/simple; bh=sFRzPeEUbfwXjETO8DhUwHf2ewNSCrg5fO2NPPdHa8o=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=qhhSq4qwgiJkvZ9iSw5cnABaNiKczf0k9MPpC4UYgqAXS+Jt1KpxG7hlHYUy2AAKmmQnt3XfPcXlkZT+BXEjaRk13Vz+SbVrjSZgck67J3u/wPHA0UqDeC9CwvizJ8NMfpGfbx0jeHA17pawcBMmRKiOpSrFbuKXINKGI3DrV28= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=sina.com; spf=pass smtp.mailfrom=sina.com; dkim=pass (1024-bit key) header.d=sina.com header.i=@sina.com header.b=hKmFhFJG; arc=none smtp.client-ip=202.108.3.17 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=sina.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=sina.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=sina.com header.i=@sina.com header.b="hKmFhFJG" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sina.com; s=201208; t=1758248350; bh=Y803CjAYkloWrgedTw2DDjDhJYKKMtqAYtox1HE3UrY=; h=From:Subject:Date:Message-ID; b=hKmFhFJGSauBJZrcWOCTBqa/QC2ONZqZmxGGAwhAjCeMxVai3c/nHO/Smr1YZ2mda rDQa0NT8f+8LWzxGpeXiIj1uzijhuVchmQT9E6GIznAH6yhswTC6XgkXU/W2q+qBW8 HDR8UHvtD4ewns7jexT2d0B2o6e/yd4jw6HdU9FI= X-SMAIL-HELO: localhost.localdomain Received: from unknown (HELO localhost.localdomain)([114.249.58.236]) by sina.com (10.54.253.34) with ESMTP id 68CCBD93000043EF; Fri, 19 Sep 2025 10:19:01 +0800 (CST) X-Sender: hdanton@sina.com X-Auth-ID: hdanton@sina.com Authentication-Results: sina.com; spf=none smtp.mailfrom=hdanton@sina.com; dkim=none header.i=none; dmarc=none action=none header.from=hdanton@sina.com X-SMAIL-MID: 2983136292027 X-SMAIL-UIID: 4CEB83AB8242444B9C7B570082D513D3-20250919-101901-1 From: Hillf Danton To: syzbot Cc: linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Subject: Re: [syzbot] [netfs?] INFO: task hung in vfs_utimes (3) Date: Fri, 19 Sep 2025 10:18:50 +0800 Message-ID: <20250919021852.7157-1-hdanton@sina.com> In-Reply-To: <68cca807.050a0220.28a605.0013.GAE@google.com> References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit > Date: Thu, 18 Sep 2025 17:47:03 -0700 [thread overview] > syzbot has bisected this issue to: > > commit aaec5a95d59615523db03dd53c2052f0a87beea7 > Author: Oleg Nesterov > Date: Thu Jan 2 14:07:15 2025 +0000 > > pipe_read: don't wake up the writer if the pipe is still full > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=175fa534580000 > start commit: 46a51f4f5eda Merge tag 'for-v6.17-rc' of git://git.kernel... > git tree: upstream > final oops: https://syzkaller.appspot.com/x/report.txt?x=14dfa534580000 > console output: https://syzkaller.appspot.com/x/log.txt?x=10dfa534580000 > kernel config: https://syzkaller.appspot.com/x/.config?x=8f01d8629880e620 > dashboard link: https://syzkaller.appspot.com/bug?extid=3815dce0acab6c55984e > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17692f62580000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1361f47c580000 Test Oleg's fix. #syz test upstream master --- x/net/9p/trans_fd.c +++ y/net/9p/trans_fd.c @@ -666,7 +666,6 @@ static void p9_poll_mux(struct p9_conn * 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; @@ -686,14 +685,7 @@ static int p9_fd_request(struct p9_clien 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; } --