From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ns211617.ip-188-165-215.eu ([188.165.215.42]:53771 "EHLO mx.speed47.net" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753612AbbIOOrG (ORCPT ); Tue, 15 Sep 2015 10:47:06 -0400 Received: from rc.speed47.net (nginx [192.168.80.2]) by box.speed47.net (Postfix) with ESMTP id 6B0C9391 for ; Tue, 15 Sep 2015 16:47:00 +0200 (CEST) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Date: Tue, 15 Sep 2015 16:47:00 +0200 From: =?UTF-8?Q?St=C3=A9phane_Lesimple?= To: linux-btrfs@vger.kernel.org Subject: Re: kernel BUG at linux-4.2.0/fs/btrfs/extent-tree.c:1833 on rebalance In-Reply-To: <9c864637fe7676a8b7badc5ddd7a4e0c@all.all> References: <9c864637fe7676a8b7badc5ddd7a4e0c@all.all> Message-ID: <2c00c4b7c15e424659fb2e810170e32e@all.all> Sender: linux-btrfs-owner@vger.kernel.org List-ID: > I've been experiencing repetitive "kernel BUG" occurences in the past > few days trying to balance a raid5 filesystem after adding a new drive. > It occurs on both 4.2.0 and 4.1.7, using 4.2 userspace tools. I've ran a scrub on this filesystem after the crash happened twice, and if found no errors. The BUG_ON() condition that my filesystem triggers is the following : BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID); // in insert_inline_extent_backref() of extent-tree.c. I've compiled a fresh 4.3.0-rc1 with a couple added printk's just before the BUG_ON(), to dump the parameters passed to insert_inline_extent_backref() when the problem occurs. Here is an excerpt of the resulting dmesg : {btrfs} in insert_inline_extent_backref, got owner < BTRFS_FIRST_FREE_OBJECTID {btrfs} with bytenr=4557830635520 num_bytes=16384 parent=4558111506432 root_objectid=3339 owner=1 offset=0 refs_to_add=1 BTRFS_FIRST_FREE_OBJECTID=256 ------------[ cut here ]------------ kernel BUG at fs/btrfs/extent-tree.c:1837! I'll retry with the exact same kernel once I get the machine back up, and see if the the bug happens again at the same filesystem spot or a different one. The variable amount of time after a balance start elapsed before I get the bug suggests that this would be a different one. -- Stéphane.