Re: gdb internal error when trying to get stack trace from kernel dump

[christos%astron.com@localhost (Christos Zoulas)]

In article <D524F481-144F-4CC3-AF30-5DA8CBA4C72C%azeotrope.org@localhost>,
Dave Huang  <khym%azeotrope.org@localhost> wrote:
>It seems like ever since I increased some networking-related buffer 
>sizes, my system, an AlphaPC 164 with 256MB RAM running 7.0_RC2, 
>frequently crashes when a Mac on the network starts a Time Machine 
>backup to the Alpha (which is running netatalk/afpd). The sysctls I 
>changed are:
>
>kern.sbmax=4194304
>net.inet.tcp.recvbuf_max=4194304
>net.inet.tcp.sendbuf_max=4194304
>net.inet.tcp.recvbuf_inc=131072
>net.inet.tcp.sendbuf_inc=131072
>
>and I recompiled the kernel for:
>kern.mbuf.nmbclusters = 16384
>
>The alpha crashes with the following messages:
>
>CPU 0: fatal kernel trap:
>
>CPU 0    trap entry = 0x2 (memory management fault)
>CPU 0    a0         = 0x78
>CPU 0    a1         = 0x1
>CPU 0    a2         = 0x0
>CPU 0    pc         = 0xfffffc00004c7d00
>CPU 0    ra         = 0xfffffc00004c7cc0
>CPU 0    pv         = 0xfffffc000044da70
>CPU 0    curlwp     = 0xfffffc000fe55980
>CPU 0        pid = 0, comm = system
>
>panic: trap
>cpu0: Begin traceback...
>alpha trace requires known PC =eject=
>cpu0: End traceback...
>
>So, I wanted to try to figure out what was going on, but I can't get 
>gdb to give me a stack trace:
>
># gdb netbsd.gdb
>GNU gdb (GDB) 7.7.1
>[ ... ]
>Reading symbols from netbsd.gdb...done.
>(gdb) target kvm /var/crash/netbsd.57.core
>PC not available
><unavailable> in ?? ()
>(gdb) bt
>#-1 <unavailable> in ?? ()
>#0  <unavailable> in ?? ()
>/usr/src/external/gpl3/gdb/dist/gdb/frame.c:472: internal-error:
>get_frame_id: Assertion `fi->this_id.p' failed.
>A problem internal to GDB has been detected,
>further debugging may prove unreliable.
>Quit this debugging session? (y or n) y
>
>/usr/src/external/gpl3/gdb/dist/gdb/frame.c:472: internal-error:
>get_frame_id: Assertion `fi->this_id.p' failed.
>A problem internal to GDB has been detected,
>further debugging may prove unreliable.
>Create a core file of GDB? (y or n) n
>
>Is this related to "alpha trace requires known PC" and "PC not 
>available"?

Looks like the alpha kvm support has grown stale. Can you compare the register
layout in gdb with the one in the kernel?

christos