panic: lockmgr on FreeBSD 7.0-RELEASE-p4 amd64

[Jeff Wheelhouse]

We got the same panic again, this time after switching to the ULE  
scheduler:

panic: lockmgr: thread 0xffffff0050858350, not exclusive lock holder  
0xffffff00074959f0 unlocking
cpuid = 0
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0x2a
panic() at panic+0x17a
_lockmgr() at _lockmgr+0x872
VOP_UNLOCK_APV() at VOP_UNLOCK_APV+0x46
null_unlock() at null_unlock+0xff
VOP_UNLOCK_APV() at VOP_UNLOCK_APV+0x46
nullfs_mount() at nullfs_mount+0x244
vfs_donmount() at vfs_donmount+0xe4d
nmount() at nmount+0xa5
syscall() at syscall+0x254
Xfast_syscall() at Xfast_syscall+0xab
--- syscall (378, FreeBSD ELF64, nmount), rip = 0x206845ac, rsp =  
0x7fffffffdfc8, rbp = 0x7fffffffdfd0 ---

Thanks,
Jeff

On Sep 23, 2008, at 11:51 AM, Jeff Wheelhouse wrote:

>
> Got the following panic overnight:
>
> panic: lockmgr: thread 0xffffff0053cda680, not exclusive lock holder  
> 0xffffff002d7da680 unlocking
> cpuid = 0
> KDB: stack backtrace:
> db_trace_self_wrapper() at db_trace_self_wrapper+0x2a
> panic() at panic+0x17a
> _lockmgr() at _lockmgr+0x872
> VOP_UNLOCK_APV() at VOP_UNLOCK_APV+0x46
> null_unlock() at null_unlock+0xff
> VOP_UNLOCK_APV() at VOP_UNLOCK_APV+0x46
> nullfs_mount() at nullfs_mount+0x244
> vfs_donmount() at vfs_donmount+0xe4d
> nmount() at nmount+0xa5
> syscall() at syscall+0x254
> Xfast_syscall() at Xfast_syscall+0xab
> --- syscall (378, FreeBSD ELF64, nmount), rip = 0x206845ac, rsp =  
> 0x7fffffffdfb8, rbp = 0x7fffffffdfc0 ---
>
> I've done some searches and "not exclusive lock holder" has been  
> seen before, but I didn't find any previous reports related to  
> nullfs with a stack trace at all like this on FreeBSD 7.
>
> This machine is diskless and thus cannot store a kernel dump.  Ideas/ 
> suggestions for fixes, causes or debugging steps?
>
> The kernel is amd64, with config shown below.
>
> Thanks,
> Jeff
>
> include GENERIC
>
> device  carp
> device  pf
> device  pflog
> device  pfsync
>
> options SW_WATCHDOG
> options DEVICE_POLLING
>
> options         ALTQ
> options         ALTQ_CBQ
> options         ALTQ_RED
> options         ALTQ_RIO
> options         ALTQ_HFSC
> options         ALTQ_PRIQ
> options         ALTQ_NOPCC
>
> options         KDB
> options         KDB_UNATTENDED
> options         KDB_TRACE
> options         DDB
> options         BREAK_TO_DEBUGGER
>
>
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