From mboxrd@z Thu Jan 1 00:00:00 1970 From: Miu Vlad-Cosmin Subject: writeback: Stability issue (BUG) on 4.4 with =?utf-8?b?d3JpdGViYWNrX3BlcmNlbnQ=?= Date: Thu, 14 Jan 2016 07:22:23 +0000 (UTC) Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Return-path: Received: from plane.gmane.org ([80.91.229.3]:34561 "EHLO plane.gmane.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751361AbcANHZH (ORCPT ); Thu, 14 Jan 2016 02:25:07 -0500 Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1aJcHI-00071c-Le for linux-bcache@vger.kernel.org; Thu, 14 Jan 2016 08:25:04 +0100 Received: from 188-173-3-123.next-gen.ro ([188-173-3-123.next-gen.ro]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Thu, 14 Jan 2016 08:25:04 +0100 Received: from miuvlad by 188-173-3-123.next-gen.ro with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Thu, 14 Jan 2016 08:25:04 +0100 Sender: linux-bcache-owner@vger.kernel.org List-Id: linux-bcache@vger.kernel.org To: linux-bcache@vger.kernel.org Hello, In a rather basic bcache setup (one cache + mdraid backing), I encounter a kernel problem related to bcache with 4.4.0. In order to trigger this bug, fill the cache with some dirty data. When there is some dirty data, wait for the bcache_writeback to start writing it to the backing device (0-3 minutes) and the BUG triggers. Please find more info here: https://bugzilla.kernel.org/show_bug.cgi?id=110771 [] make_request+0x47f/0xca0 [] md_make_request+0xdd/0x220 [] ? pick_next_task_fair+0x12e/0x450 [] generic_make_request+0xce/0x1b0 [] write_dirty+0x60/0xb0 [] process_one_work+0x147/0x3d0 [] worker_thread+0x46/0x440 [] ? rescuer_thread+0x2d0/0x2d0 [] ? rescuer_thread+0x2d0/0x2d0 [] kthread+0xc4/0xe0 [] ? kthread_park+0x50/0x50 [] ret_from_fork+0x3f/0x70 A bisect shows "[578270bfbd2803dc7b0b03fbc2ac119efbc73195] block: fix segment split" as the problem. Anyone can confirm this ? Thanks, Vlad