UFS related panic (daily <-> find)

[rank1seeker at gmail.com]

> > > > I had 2 panics: (Both occured at 3 AM, so had to be daily task)
> > > > 
> > > > First (Jul  2 03:06:50 2013):
> > > > --
> > > > Fatal trap 12: page fault while in kernel mode
> > > > fault virtual address   = 0x19
> > > > fault code              = supervisor read, page not present
> > > > instruction pointer     = 0x20:0xc06caf34
> > > > stack pointer           = 0x28:0xe76248fc
> > > > frame pointer           = 0x28:0xe7624930
> > > > code segment            = base 0x0, limit 0xfffff, type 0x1b
> > > >                         = DPL 0, pres 1, def32 1, gran 1
> > > > processor eflags        = interrupt enabled, resume, IOPL = 0
> > > > current process         = 76562 (find)
> > > > trap number             = 12
> > > > panic: page fault
> > > > Uptime: 23h0m41s
> > > > Physical memory: 1014 MB
> > > > Dumping 186 MB: 171 155 139 123 107 91 75 59 43 27 11
> > > > 
> > > > #7  0xc06caf34 in cache_lookup_times (dvp=0xc784a990, 
vpp=0xe7624ae8,
> > > >     cnp=0xe7624afc, tsp=0x0, ticksp=0x0) at 
> > > /usr/src/sys/kern/vfs_cache.c:547
> > > 
> > > Can you go up to this frame and do 'l'?
> > > 
> > > -- 
> > > John Baldwin
> > 
> > 
> > Sure,
> > 
> > ---------
> > (kgdb) up 7
> > #7  0xc06caf34 in cache_lookup_times (dvp=0xc784a990, vpp=0xe7624ae8, 
cnp=0xe7624afc, tsp=0x0, ticksp=0x0) at /usr/src/sys/kern/vfs_cache.c:547
> > 547                     numchecks++;
> > ---------
> > (kgdb) l
> > 542             }
> > 543
> > 544             hash = fnv_32_buf(cnp->cn_nameptr, cnp->cn_namelen, 
FNV1_32_INIT);
> > 545             hash = fnv_32_buf(&dvp, sizeof(dvp), hash);
> > 546             LIST_FOREACH(ncp, (NCHHASH(hash)), nc_hash) {
> > 547                     numchecks++;
> > 548                     if (ncp->nc_dvp == dvp && ncp->nc_nlen == 
cnp->cn_namelen &&
> > 549                         !bcmp(nc_get_name(ncp), cnp->cn_nameptr, 
ncp->nc_nlen))
> > 550                             break;
> > 551             }
> > ---------
> 
> Hmm, 'p ncp' and 'p *ncp' at that frame perhaps?
> 

(kgdb) p ncp
$1 = (struct namecache *) 0x1
(kgdb) p *ncp
Cannot access memory at address 0x1