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

[Frederic MASSOT]

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
*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