From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from infao0809.mpi-klsb.mpg.de ([139.19.1.49]:36432 "EHLO hera.mpi-klsb.mpg.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752001Ab3J2Dip (ORCPT ); Mon, 28 Oct 2013 23:38:45 -0400 Message-ID: <526F2DBF.4090404@mpi-sws.org> Date: Tue, 29 Oct 2013 04:38:39 +0100 From: Pedro Fonseca MIME-Version: 1.0 To: bo.li.liu@oracle.com CC: linux-btrfs@vger.kernel.org Subject: Re: Null pointer dereference bug in btrfs_find_all_root References: <526E8A83.4030201@mpi-sws.org> <20131029020554.GA32338@localhost.localdomain> In-Reply-To: <20131029020554.GA32338@localhost.localdomain> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Sender: linux-btrfs-owner@vger.kernel.org List-ID: On 10/29/13 3:05 AM, Liu Bo wrote: > Hi, > > On Mon, Oct 28, 2013 at 05:02:11PM +0100, Pedro Fonseca wrote: >> Hi, >> >> I've encountered a few NULL pointer dereference bugs while running a >> custom test case on btrfs (kernel 3.11.1), inside a QEMU based VM. >> >> Btrfs was statically compiled and the btrfs filesystem was mounted >> on one or two loop devices. All cases occurred during execution of a >> "filesystem balance" operation and while another file system >> operation was concurrently executed. In one case the other operation >> was a "mknod" and in another it was a "filesystem show" operation. > I'm wonderring that if there is anything like 'aborted transaction' in > the dmesg log besides this NULL pointer dereference? > > -liubo No, I didn't find any references to aborted transactions. But I did get a message about "relocation of block groups" and a few other messages caused by resizing operations. These are all the filesystem messages I got before the actual bug report: [ 111.836409] loop: module loaded [ 112.939586] device fsid acb9f83e-75d7-4177-9f7b-4b7c8e0f53d9 devid 1 transid 7 /dev/loop0 [ 122.328339] btrfs: new size for /dev/loop0 is 311427072 [ 122.396188] btrfs: new size for /dev/loop0 is 301989888 [ 122.646333] btrfs: new size for /dev/loop0 is 299892736 [ 127.788383] btrfs: new size for /dev/loop0 is 305135616 [ 127.830656] btrfs: relocating block group 20971520 flags 1 >> In all cases the NULL pointer dereference occurred in the >> "btrfs_find_all_roots" function and all cases produced a bug report >> similar to the one bellow: >> >>> [ 138.573390] BUG: unable to handle kernel NULL pointer >>> dereference at (null) >>> [ 138.573390] IP: [] ulist_next+0x4/0x26 >>> [ 138.573390] *pde = 00000000 >>> [ 138.573390] Oops: 0000 [#1] SMP >>> [ 138.573390] Modules linked in: loop rtc_cmos pcspkr tpm_tis >>> freq_table mperf i2c_piix4 >>> [ 138.573390] CPU: 0 PID: 2794 Comm: btrfs-endio-wri Not tainted >>> 3.11.1 #2 >>> [ 138.573390] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2007 >>> [ 138.573390] task: c5dea6b0 ti: c5e12000 task.ti: c5e12000 >>> [ 138.573390] EIP: 0060:[] EFLAGS: 00000246 CPU: 0 >>> [ 138.573390] EIP is at ulist_next+0x4/0x26 >>> [ 138.573390] EAX: 00000000 EBX: 00000000 ECX: d9c29e38 EDX: c5e13da4 >>> [ 138.573390] ESI: 00000000 EDI: c5e13e00 EBP: c5e13d94 ESP: c5e13d90 >>> [ 138.573390] DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068 >>> [ 138.573390] CR0: 8005003b CR2: 00000000 CR3: 059d8000 CR4: 00000690 >>> [ 138.573390] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000 >>> [ 138.573390] DR6: 00000000 DR7: 00000000 >>> [ 138.573390] Stack: >>> [ 138.573390] 00000000 c5e13db4 c12fe7b8 de4d1000 d9cead48 >>> 00000001 010dd000 deeab810 >>> [ 138.573390] 00000001 c5e13e10 c12fe8cf 00af2000 00000000 >>> 00000000 00000003 c5e13e00 >>> [ 138.573390] deeabe00 00000000 00000003 deeab800 de4d1000 >>> d9cead48 de4d14b8 de4d14b8 >>> [ 138.573390] Call Trace: >>> [ 138.573390] [] btrfs_find_all_roots+0x88/0xa6 >>> [ 138.573390] [] iterate_extent_inodes+0xf9/0x1b2 >>> [ 138.573390] [] iterate_inodes_from_logical+0x88/0x97 >>> [ 138.573390] [] ? record_extent_backrefs+0x8b/0x8b >>> [ 138.573390] [] record_extent_backrefs+0x50/0x8b >>> [ 138.573390] [] ? record_extent_backrefs+0x8b/0x8b >>> [ 138.573390] [] btrfs_finish_ordered_io+0x77e/0x876 >>> [ 138.573390] [] finish_ordered_fn+0xb/0xd >>> [ 138.573390] [] worker_loop+0x111/0x3ec >>> [ 138.573390] [] ? default_wake_function+0xb/0xd >>> [ 138.573390] [] kthread+0x90/0x95 >>> [ 138.573390] [] ? btrfs_queue_worker+0x1c8/0x1c8 >>> [ 138.573390] [] ret_from_kernel_thread+0x1b/0x28 >>> [ 138.573390] [] ? kthread_freezable_should_stop+0x4f/0x4f >>> [ 138.573390] Code: 5b 5e 5f 5d c3 90 90 90 55 8d 50 10 89 e5 c7 >>> 00 00 00 00 00 89 50 08 c7 40 04 10 00 00 00 c7 40 0c 00 00 00 00 >>> 5d c3 55 89 e5 53 <8b> 08 85 c9 74 15 8b 1a 85 db 78 0f 39 cb 73 >>> 0b 6b cb 1c 43 03 >>> [ 138.573390] EIP: [] ulist_next+0x4/0x26 SS:ESP 0068:c5e13d90 >>> [ 138.573390] CR2: 0000000000000000 >>> [ 138.573390] ---[ end trace 626899e11111abbe ]--- >>> [ 138.573390] BUG: unable to handle kernel NULL pointer >>> dereference at (null) >>> [ 138.573390] IP: [] ulist_next+0x4/0x26 >>> [ 138.573390] *pde = 00000000 >>> [ 138.573390] Oops: 0000 [#2] SMP >>> [ 138.573390] Modules linked in: loop rtc_cmos pcspkr tpm_tis >>> freq_table mperf i2c_piix4 >>> [ 138.573390] CPU: 1 PID: 2793 Comm: btrfs-endio-wri Tainted: G >>> D 3.11.1 #2 >>> [ 138.573390] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2007 >>> [ 138.573390] task: c59cc190 ti: dedc8000 task.ti: dedc8000 >>> [ 138.573390] EIP: 0060:[] EFLAGS: 00000246 CPU: 1 >>> [ 138.573390] EIP is at ulist_next+0x4/0x26 >>> [ 138.573390] EAX: 00000000 EBX: 00000000 ECX: d9c296c8 EDX: dedc9da4 >>> [ 138.573390] ESI: 00000000 EDI: dedc9e00 EBP: dedc9d94 ESP: dedc9d90 >>> [ 138.573390] DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068 >>> [ 138.573390] CR0: 8005003b CR2: 00000000 CR3: 03ebe000 CR4: 00000690 >>> [ 138.573390] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000 >>> [ 138.573390] DR6: 00000000 DR7: 00000000 >>> [ 138.573390] Stack: >>> [ 138.573390] 00000000 dedc9db4 c12fe7b8 de4d1000 d9ceaf50 >>> 00000001 00dea000 de4c6410 >>> [ 138.573390] 00000001 dedc9e10 c12fe8cf 00af2000 00000000 >>> 00000000 00000005 dedc9e00 >>> [ 138.573390] de4c6c00 00000000 00000005 de4c6400 de4d1000 >>> d9ceaf50 de4d14b8 c5e13de8 >>> [ 138.573390] Call Trace: >>> [ 138.573390] [] btrfs_find_all_roots+0x88/0xa6 >>> [ 138.573390] [] iterate_extent_inodes+0xf9/0x1b2 >>> [ 138.573390] [] iterate_inodes_from_logical+0x88/0x97 >>> [ 138.573390] [] ? record_extent_backrefs+0x8b/0x8b >>> [ 138.573390] [] record_extent_backrefs+0x50/0x8b >>> [ 138.573390] [] ? record_extent_backrefs+0x8b/0x8b >>> [ 138.573390] [] btrfs_finish_ordered_io+0x77e/0x876 >>> [ 138.573390] [] finish_ordered_fn+0xb/0xd >>> [ 138.573390] [] worker_loop+0x111/0x3ec >>> [ 138.573390] [] ? default_wake_function+0xb/0xd >>> [ 138.573390] [] kthread+0x90/0x95 >>> [ 138.573390] [] ? btrfs_queue_worker+0x1c8/0x1c8 >>> [ 138.573390] [] ret_from_kernel_thread+0x1b/0x28 >>> [ 138.573390] [] ? kthread_freezable_should_stop+0x4f/0x4f >>> [ 138.573390] Code: 5b 5e 5f 5d c3 90 90 90 55 8d 50 10 89 e5 c7 >>> 00 00 00 00 00 89 50 08 c7 40 04 10 00 00 00 c7 40 0c 00 00 00 00 >>> 5d c3 55 89 e5 53 <8b> 08 85 c9 74 15 8b 1a 85 db 78 0f 39 cb 73 >>> 0b 6b cb 1c 43 03 >>> [ 138.573390] EIP: [] ulist_next+0x4/0x26 SS:ESP 0068:dedc9d90 >>> [ 138.573390] CR2: 0000000000000000 >>> [ 138.573390] ---[ end trace 626899e11111abbf ]--- > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html