Bug#539649: checkarray: BUG: unable to handle kernel NULL pointer dereference at 00000003

[NeilBrown]

On Mon, August 3, 2009 3:41 am, Frederic MASSOT wrote:
> Package: mdadm
> Version: 2.6.9-3
> Severity: normal
>
>
> Hi,
>
> When checkarray, the mark "-- MARK --" was not written to the file
> "/var/log/messages" by rsyslog and watchdog restarts the server. I have
> this problem on several server.
>
> On another server with watchdog not active, I had these messages with the
> dmesg command, it was not written in the logs.
>
> md: data-check of RAID array md0
> md: minimum _guaranteed_  speed: 1000 KB/sec/disk.
> md: using maximum available idle IO bandwidth (but not more than 200000
> KB/sec) for data-check.
> md: using 128k window, over a total of 96256 blocks.
> BUG: unable to handle kernel NULL pointer dereference at 00000003
> IP: [<c014724b>] put_page+0x6/0xdd

I believe this is the kernel bug that was fixed my upstream
  commit 303a0e11d0ee136ad8f53f747f3c377daece763b

http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=303a0e11d0ee136ad8f53f747f3c377daece763b

NeilBrown


> *pde = 00000000
> Oops: 0000 [#1] SMP
> last sysfs file: /sys/block/md1/md/sync_action
> Modules linked in:
>
> Pid: 19080, comm: md0_resync Not tainted (2.6.29 #1) System Product Name
> EIP: 0060:[<c014724b>] EFLAGS: 00010206 CPU: 1
> EIP is at put_page+0x6/0xdd
> EAX: 00000003 EBX: 00000003 ECX: 00000060 EDX: f738a878
> ESI: 0000003c EDI: dd26e180 EBP: dd26e1b8 ESP: d5547e2c
>  DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068
> Process md0_resync (pid: 19080, ti=d5547000 task=c3ba0990
> task.ti=d5547000)
> Stack:
>  00000000 0000003c dd26e180 dd26e1b8 c02bbcb1 00011200 f738a878 f7087500
>  d0a28640 f738d200 00011210 d0a2865c c014235c 00000010 00000082 f70a2428
>  f70a2400 f70a2428 f70a2400 00000001 f738d200 0002f000 c3cbfa00 c02bbece
> Call Trace:
>  [<c02bbcb1>] r1buf_pool_alloc+0x11c/0x164
>  [<c014235c>] mempool_alloc+0x27/0xcb
>  [<c02bbece>] sync_request+0x175/0x4bc
>  [<c0116f4a>] __wake_up+0x29/0x39
>  [<c02c9c14>] md_do_sync+0x582/0x901
>  [<c02ca390>] md_thread+0xde/0xf5
>  [<c0116ed5>] complete+0x28/0x36
>  [<c02ca2b2>] md_thread+0x0/0xf5
>  [<c012d3b4>] kthread+0x38/0x5d
>  [<c012d37c>] kthread+0x0/0x5d
>  [<c010340b>] kernel_thread_helper+0x7/0x10
> Code: 52 c0 64 8b 15 00 05 52 c0 8d 14 10 8b 02 89 4c 82 08 40 89 02 83 f8
> 0e 75 07 89 d0 e8 44 fe ff ff 53 9d 5b c3 55 57 56 53 89 c3 <8b> 00 f6 c4
> 60 74 23 f6 c4 40 74 03 8b 5b 0c 8d 43 04 f0 ff 08
> EIP: [<c014724b>] put_page+0x6/0xdd SS:ESP 0068:d5547e2c
> ---[ end trace 8b61c23ebcbabaed ]---
> md: delaying data-check of md1 until md0 has finished (they share one or
> more physical units)
>
> And mdstat contains:
> $ cat /proc/mdstat
> Personalities : [raid1] [raid6] [raid5] [raid4]
> md1 : active raid5 sda2[0] sdd2[3] sdc2[2] sdb2[1]
>       937416576 blocks level 5, 64k chunk, algorithm 2 [4/4] [UUUU]
>       	resync=DELAYED
>
> md0 : active raid1 sda1[0] sdd1[3] sdc1[2] sdb1[1]
>       96256 blocks [4/4] [UUUU]
>       [>....................]  check =  0.0% (384/96256)
> finish=585519.5min speed=0K/sec
>
> unused devices: <none>
>
>
>
>
> Regards.
>
>
> -- Package-specific info:
>
> -- System Information:
> Debian Release: squeeze/sid
>   APT prefers testing
>   APT policy: (500, 'testing'), (500, 'stable')
> Architecture: i386 (i686)
>
> Kernel: Linux 2.6.29 (SMP w/2 CPU cores)
> Locale: LANG=fr_FR.UTF-8, LC_CTYPE=fr_FR.UTF-8 (charmap=UTF-8)
> Shell: /bin/sh linked to /bin/dash
>
> Versions of packages mdadm depends on:
> ii  debconf                       1.5.27     Debian configuration
> management sy
> ii  libc6                         2.9-12     GNU C Library: Shared
> libraries
> ii  lsb-base                      3.2-22     Linux Standard Base 3.2 init
> scrip
> ii  makedev                       2.3.1-88   creates device files in /dev
> ii  udev                          0.141-1    /dev/ and hotplug management
> daemo
>
> Versions of packages mdadm recommends:
> ii  module-init-tools            3.9-2       tools for managing Linux
> kernel mo
> ii  postfix [mail-transport-agen 2.6.2~rc1-1 High-performance mail
> transport ag
>
> mdadm suggests no packages.
>
> -- debconf information:
>   mdadm/autostart: true
>   mdadm/mail_to: root
>   mdadm/initrdstart_msg_errmd:
> * mdadm/initrdstart: all
>   mdadm/initrdstart_msg_errconf:
>   mdadm/initrdstart_notinconf: false
>   mdadm/initrdstart_msg_errexist:
>   mdadm/initrdstart_msg_intro:
>   mdadm/autocheck: true
>   mdadm/initrdstart_msg_errblock:
>   mdadm/start_daemon: true
>
>
>
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