[DRBD-user] Kernel 2.6.20+ Drbd 8.0.0 (2738M): BUG: unable to handle kernel NULL pointer

[Martin Bene]

Hi, I'm seeing the above error in one of the scenarios I'm testing:

* Kernel 2.6.20
* drbd 8.0.0, SVN Revision 2738
* 2 drbd devices

I've seen the above bug several times, most recently after hard
resetting a node that was primary for one of the devices.

On reboot I got the following bug in kernel logs:

Feb 14 10:37:17 webc-neu2 kernel: drbd: initialised. Version: 8.0.0
(api:86/proto:86)
Feb 14 10:37:17 webc-neu2 kernel: drbd: SVN Revision: 2738M build by
root at webc-neu2, 2007-02-06 14:56:34
Feb 14 10:37:17 webc-neu2 kernel: drbd: registered as block device major
147
Feb 14 10:37:17 webc-neu2 kernel: drbd: minor_table @ 0xf7a888c0
Feb 14 10:37:17 webc-neu2 kernel: drbd0: disk( Diskless -> Attaching )
Feb 14 10:37:17 webc-neu2 kernel: drbd0: Found 6 transactions (276
active extents) in activity log.
Feb 14 10:37:17 webc-neu2 kernel: drbd0: max_segment_size ( = BIO size )
= 32768
Feb 14 10:37:17 webc-neu2 kernel: drbd0: drbd_bm_resize called with
capacity == 58586936
Feb 14 10:37:17 webc-neu2 kernel: drbd0: resync bitmap: bits=7323367
words=228856
Feb 14 10:37:17 webc-neu2 kernel: drbd0: size = 27 GB (29293468 KB)
Feb 14 10:37:17 webc-neu2 kernel: drbd0: reading of bitmap took 8
jiffies
Feb 14 10:37:17 webc-neu2 kernel: drbd0: recounting of set bits took
additional 0 jiffies
Feb 14 10:37:17 webc-neu2 kernel: drbd0: 0 KB marked out-of-sync by on
disk bit-map.
Feb 14 10:37:17 webc-neu2 kernel: drbd0: Marked additional 1026 MB as
out-of-sync based on AL.
Feb 14 10:37:17 webc-neu2 kernel: drbd0: disk( Attaching -> UpToDate )
Feb 14 10:37:17 webc-neu2 kernel: drbd0: Writing meta data super block
now.
Feb 14 10:37:17 webc-neu2 kernel: drbd1: disk( Diskless -> Attaching )
Feb 14 10:37:17 webc-neu2 kernel: drbd1: Found 6 transactions (324
active extents) in activity log.
Feb 14 10:37:17 webc-neu2 kernel: drbd1: max_segment_size ( = BIO size )
= 32768
Feb 14 10:37:17 webc-neu2 kernel: drbd1: drbd_bm_resize called with
capacity == 58586936
Feb 14 10:37:17 webc-neu2 kernel: drbd1: resync bitmap: bits=7323367
words=228856
Feb 14 10:37:17 webc-neu2 kernel: drbd1: size = 27 GB (29293468 KB)
Feb 14 10:37:17 webc-neu2 kernel: drbd1: reading of bitmap took 11
jiffies
Feb 14 10:37:17 webc-neu2 kernel: drbd1: recounting of set bits took
additional 0 jiffies
Feb 14 10:37:17 webc-neu2 kernel: drbd1: 0 KB marked out-of-sync by on
disk bit-map.
Feb 14 10:37:17 webc-neu2 kernel: drbd1: disk( Attaching -> UpToDate )
Feb 14 10:37:17 webc-neu2 kernel: drbd1: Writing meta data super block
now.
Feb 14 10:37:17 webc-neu2 kernel: drbd0: conn( StandAlone -> Unconnected
)
Feb 14 10:37:17 webc-neu2 kernel: drbd0: receiver (re)started
Feb 14 10:37:17 webc-neu2 kernel: drbd0: conn( Unconnected ->
WFConnection )
Feb 14 10:37:17 webc-neu2 kernel: drbd1: conn( StandAlone -> Unconnected
)
Feb 14 10:37:17 webc-neu2 kernel: drbd1: receiver (re)started
Feb 14 10:37:17 webc-neu2 kernel: drbd1: conn( Unconnected ->
WFConnection )
Feb 14 10:37:17 webc-neu2 kernel: BUG: unable to handle kernel NULL
pointer dereference at virtual address 00000000
Feb 14 10:37:17 webc-neu2 kernel:  printing eip:
Feb 14 10:37:17 webc-neu2 kernel: 00000000
Feb 14 10:37:17 webc-neu2 kernel: *pde = 00000000
Feb 14 10:37:17 webc-neu2 kernel: Oops: 0000 [#1]
Feb 14 10:37:17 webc-neu2 kernel: SMP
Feb 14 10:37:17 webc-neu2 kernel: Modules linked in: drbd usbcore sha1
ipmi_devintf ipmi_si ipmi_msghandler nfs lockd sunrpc tg3 iTCO_wdt
Feb 14 10:37:17 webc-neu2 kernel: CPU:    1
Feb 14 10:37:17 webc-neu2 kernel: EIP:    0060:[_proxy_pda+0/1048576]
Not tainted VLI
Feb 14 10:37:17 webc-neu2 kernel: EIP:    0060:[<00000000>]    Not
tainted VLI
Feb 14 10:37:17 webc-neu2 kernel: EFLAGS: 00010247   (2.6.20-gentoo #2)
Feb 14 10:37:17 webc-neu2 kernel: EIP is at _stext+0x3feffc6c/0x20
Feb 14 10:37:17 webc-neu2 kernel: eax: f79d7c10   ebx: f732c608   ecx:
c2169358   edx: 00000286
Feb 14 10:37:17 webc-neu2 kernel: esi: f732c5cc   edi: f732c5cc   ebp:
00000286   esp: c229df40
Feb 14 10:37:17 webc-neu2 kernel: ds: 007b   es: 007b   ss: 0068
Feb 14 10:37:17 webc-neu2 kernel: Process cqueue/1 (pid: 127,
ti=c229c000 task=c2267550 task.ti=c229c000)
Feb 14 10:37:17 webc-neu2 kernel: Stack: c0261f69 f732c5d0 c2169340
c0125957 0000021b 13a32329 00000007 f7f4d030
Feb 14 10:37:17 webc-neu2 kernel:        c0261f5c c2169340 c2169340
c229df80 fffffffc c0125b01 ffffffff ffffffff
Feb 14 10:37:17 webc-neu2 kernel:        00000001 00000000 c0113891
00010000 00000000 c213da70 00000000 c200c900
Feb 14 10:37:17 webc-neu2 kernel: Call Trace:
Feb 14 10:37:17 webc-neu2 kernel:  [cn_queue_wrapper+13/36]
cn_queue_wrapper+0xd/0x24
Feb 14 10:37:17 webc-neu2 kernel:  [<c0261f69>]
cn_queue_wrapper+0xd/0x24
Feb 14 10:37:17 webc-neu2 kernel:  [run_workqueue+138/292]
run_workqueue+0x8a/0x124
Feb 14 10:37:17 webc-neu2 kernel:  [<c0125957>] run_workqueue+0x8a/0x124
Feb 14 10:37:17 webc-neu2 kernel:  [cn_queue_wrapper+0/36]
cn_queue_wrapper+0x0/0x24
Feb 14 10:37:17 webc-neu2 kernel:  [<c0261f5c>]
cn_queue_wrapper+0x0/0x24
Feb 14 10:37:17 webc-neu2 kernel:  [worker_thread+272/315]
worker_thread+0x110/0x13b
Feb 14 10:37:17 webc-neu2 kernel:  [<c0125b01>]
worker_thread+0x110/0x13b
Feb 14 10:37:17 webc-neu2 kernel:  [default_wake_function+0/12]
default_wake_function+0x0/0xc
Feb 14 10:37:17 webc-neu2 kernel:  [<c0113891>]
default_wake_function+0x0/0xc
Feb 14 10:37:17 webc-neu2 kernel:  [default_wake_function+0/12]
default_wake_function+0x0/0xc
Feb 14 10:37:17 webc-neu2 kernel:  [<c0113891>]
default_wake_function+0x0/0xc
Feb 14 10:37:17 webc-neu2 kernel:  [worker_thread+0/315]
worker_thread+0x0/0x13b
Feb 14 10:37:17 webc-neu2 kernel:  [<c01259f1>] worker_thread+0x0/0x13b
Feb 14 10:37:17 webc-neu2 kernel:  [kthread+116/152] kthread+0x74/0x98
Feb 14 10:37:17 webc-neu2 kernel:  [<c0128614>] kthread+0x74/0x98
Feb 14 10:37:17 webc-neu2 kernel:  [kthread+0/152] kthread+0x0/0x98
Feb 14 10:37:17 webc-neu2 kernel:  [<c01285a0>] kthread+0x0/0x98
Feb 14 10:37:17 webc-neu2 kernel:  [kernel_thread_helper+7/16]
kernel_thread_helper+0x7/0x10
Feb 14 10:37:17 webc-neu2 kernel:  [<c0103473>]
kernel_thread_helper+0x7/0x10
Feb 14 10:37:17 webc-neu2 kernel:  =======================
Feb 14 10:37:17 webc-neu2 kernel: Code:  Bad EIP value.
Feb 14 10:37:17 webc-neu2 kernel: EIP: [_proxy_pda+0/1048576]
_stext+0x3feffc6c/0x20 SS:ESP 0068:c229df40
Feb 14 10:37:17 webc-neu2 kernel: EIP: [<00000000>]
_stext+0x3feffc6c/0x20 SS:ESP 0068:c229df40
Feb 14 10:37:20 webc-neu2 kernel:  <6>drbd0: conn( WFConnection ->
WFReportParams )
Feb 14 10:37:20 webc-neu2 kernel: drbd0: Handshake successful: DRBD
Network Protocol version 86
Feb 14 10:37:20 webc-neu2 kernel: drbd0: Peer authenticated using 20
bytes of 'sha1' HMAC
Feb 14 10:37:20 webc-neu2 kernel: drbd0: peer( Unknown -> Secondary )
conn( WFReportParams -> WFBitMapS ) pdsk( DUnknown -> UpToDate )
Feb 14 10:37:20 webc-neu2 kernel: drbd1: conn( WFConnection ->
WFReportParams )
Feb 14 10:37:20 webc-neu2 kernel: drbd1: Handshake successful: DRBD
Network Protocol version 86
Feb 14 10:37:20 webc-neu2 kernel: drbd1: Peer authenticated using 20
bytes of 'sha1' HMAC
Feb 14 10:37:20 webc-neu2 kernel: drbd1: peer( Unknown -> Secondary )
conn( WFReportParams -> Connected ) pdsk( DUnknown -> UpToDate )
Feb 14 10:37:20 webc-neu2 kernel: drbd1: Writing meta data super block
now.
Feb 14 10:37:20 webc-neu2 kernel: drbd0: Writing meta data super block
now.
Feb 14 10:37:20 webc-neu2 kernel: drbd0: conn( WFBitMapS -> SyncSource )
pdsk( UpToDate -> Inconsistent )
Feb 14 10:37:20 webc-neu2 kernel: drbd1: aftr_isp( 0 -> 1 )

Any Idea what's going on?

Thanks, Martin