Re: panic: mutex Giant owned at .../base/head/sys/kern/kern_exit.c:131

On Friday 31 July 2009 2:36:46 am Marcel Moolenaar wrote:
> All,
> 
> I got the following panic after I had to import my ZFS file system on  
> ia64.
> The following panic happened when executing "zpool import":
> 
> panic: mutex Giant owned at /nfs/freebsd/base/head/sys/kern/ 
> kern_exit.c:131
> cpuid = 0
> KDB: enter: panic

It looks like ZFS doesn't actually ever check if any of the namei lookups it 
does internally return with Giant locked.  For example, it doesn't check 
NDHASGIANT() in lookupnameat().  Fixing this may be a bit of work as I'm not 
sure it is safe to drop Giant right after the namei().  If it is because the 
end vnode's returned are always MPSAFE then that fix is easy.  If not, then 
Giant needs to be held until the code stops frobbing the vnode returned from 
the lookup.

-- 
John Baldwin