Garbled output from kgdb?

John Baldwin jhb at freebsd.org
Fri May 1 15:53:57 UTC 2009


On Wednesday 29 April 2009 4:28:09 pm Alan Amesbury wrote:
> One of my systems (FreeBSD 7.1-RELEASE-p3/amd64) has panicked a couple
> times recently without an identified cause.  This most recent time I was
> able to obtain a crash dump from the system, but output from kgdb is
> garbled.
> 
> -------------------- Output #1 --------------------
> % pwd
> /usr/obj/usr/src/sys/[REDACTED]
> % sudo kgdb kernel.debug ~/crash/vmcore.0
> GNU gdb 6.1.1 [FreeBSD]
> Copyright 2004 Free Software Foundation, Inc.
> GDB is free software, covered by the GNU General Public License, and you are
> welcome to change it and/or distribute copies of it under certain
> conditions.
> Type "show copying" to see the conditions.
> There is absolutely no warranty for GDB.  Type "show warranty" for details.
> This GDB was configured as "amd64-marcel-freebsd"...
> 
> Unread portion of the kernel message buffer:
> kernel trap 12 with interrupts disabled
> 
> 
> Fatal trap 12: page fault while in kernel mode
> cpuid = 3; apic id = 07
> fault virtual addresske rn= el0 xt60r
> afapul t 1co2de                 w= isutpehrv isiorn twerritreu pdtasta
> d,i spaagbe lnoet dpres
> ent
> instruction pointer     = 0x8:0xffffffff80424561
> s
> tack
>  pFoianttera     l        = 0x10t:0xfffrffaffpfac057af0
> frame pointer           = 0x10:0xffffff00010f86e0
> code segment            = base 0x0, limit 0xfffff, type 0x1b
>                         = DPL 0, pres 1, long 1, def32 0, gran 1
> processor eflags        = resume, IOPL = 0
> current process         = 11 (idle: cpu3)
> trap number             = 12
> panic: page fault
> cpuid = 3
> Uptime: 40d10h35m18s
> Physical memory: 8176 MB
> Dumping 691 MB: 676 660 644 628 612 596 580 564 548 532 516 500 484 468
> 452 436 420 404 388 372 356 340 324 308 292 276 260 244 228 212 196 180
> 164 148 132 116 100 84 68 52 36 20 4
> 
> Reading symbols from /boot/kernel/daemon_saver.ko...Reading symbols from
> /boot/kernel/daemon_saver.ko.symbols...done.
> done.
> Loaded symbols for /boot/kernel/daemon_saver.ko
> #0  doadump () at pcpu.h:195
> 195             __asm __volatile("movq %%gs:0,%0" : "=r" (td));
> (kgdb) list *0x8:0xffffffff80424561
> A syntax error in expression, near `:0xffffffff80424561'.

Drop the '0x8:' from this and it will work better.  Also, 'bt' output would be 
good.

-- 
John Baldwin


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