Re: Retrieving info from panics while in X

So this panic happened again. Here's some information about it:

lizzy:~% sudo kgdb /usr/obj/usr/src/sys/LIZZY/kernel.debug crash/vmcore.0
kgdb: kvm_nlist(_stopped_cpus): 
kgdb: kvm_nlist(_stoppcbs): 
[GDB will not be able to debug user-mode threads: /usr/lib/libthread_db.so: Undefined symbol "ps_pglobal_lookup"]
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Unread portion of the kernel message buffer:
Slab at 0xc4d1efa8, freei 8 = 0.
panic: Duplicate free of item 0xc4d1e800 from zone 0xc0c45080(mbuf_packet)

Uptime: 8h43m17s
Physical memory: 1018 MB
Dumping 172 MB: 157 141 125 109 93 77 61 45 29 13

#0  doadump () at pcpu.h:166
166     pcpu.h: No such file or directory.
        in pcpu.h
(kgdb) bt
#0  doadump () at pcpu.h:166
#1  0xc04c4250 in boot (howto=260) at /usr/src/sys/kern/kern_shutdown.c:409
#2  0xc04c44fb in panic (
    fmt=0xc0610aa7 "Duplicate free of item %p from zone %p(%s)\n")
    at /usr/src/sys/kern/kern_shutdown.c:565
#3  0xc058cc0c in uma_dbg_free (zone=0xc0c45080, slab=0xc4d1efa8, 
    item=0xc4d1e800) at /usr/src/sys/vm/uma_dbg.c:302
#4  0xc058b43f in uma_zfree_arg (zone=0xc0c45080, item=0xc4d1e800, udata=0x0)
    at /usr/src/sys/vm/uma_core.c:2269
#5  0xc04ff1c1 in mb_free_ext (m=0xc4d1e800) at uma.h:303
#6  0xc04ff02e in m_freem (mb=0x0) at mbuf.h:446
#7  0xc0723b4c in ?? ()
#8  0xc4d1e800 in ?? ()
#9  0xc30ae800 in ?? ()
#10 0x00000100 in ?? ()
#11 0xc3080000 in ?? ()
#12 0xc3080000 in ?? ()
#13 0xc30801cc in ?? ()
#14 0x00000018 in ?? ()
#15 0xe35bdcc8 in ?? ()
#16 0xc072852b in ?? ()
#17 0xc30801cc in ?? ()
#18 0x00000000 in ?? ()
#19 0xc0733ae5 in ?? ()
#20 0x000004e9 in ?? ()
#21 0xc3032780 in ?? ()
#22 0x00000001 in ?? ()
#23 0xe35bdca8 in ?? ()
#24 0xc04d9bcf in critical_exit () at kern_switch.c:625
Previous frame inner to this frame (corrupt stack?)
(kgdb) 

Let me know what other bits of info you need in order to debug this.

-- 
Jos Backus
jos at catnook.com