Subject: port-i386/723: kernel post-mortems on i386 don't work
To: None <gnats-admin@NetBSD.ORG>
From: John Kohl <jtk@kolvir.blrc.ma.us>
List: netbsd-bugs
Date: 01/10/1995 18:20:10
>Number:         723
>Category:       port-i386
>Synopsis:       kernel post-mortems on i386 don't work
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    gnats-admin (GNATS administrator)
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Jan 10 18:20:06 1995
>Originator:     John Kohl
>Organization:
NetBSD Kernel Hackers `R` Us
>Release:        1.0A
>Environment:
	
System: NetBSD kolvir 1.0A NetBSD 1.0A (KOLVIR) #39: Wed Dec 21 22:18:44 EST 1994 jtk@kolvir:/u1/NetBSD-current/src/sys/arch/i386/compile/KOLVIR i386


>Description:
'gdb -k' doesn't work properly for debugging i386 crash dumps.

It looks like libkvm is missing support in kvm_i386.c:_kvm_kvatop().

I also noticed that the call to kvm_open() from gdb's
kcorelow.c:kcore_open() doesn't pass in the symbol file name--making it
default to /netbsd.

>How-To-Repeat:
	Try to debug a crash dump, you'll get something like:

# gdb -k netbsd.1 vmcore.1 
(no debugging symbols found)...
/usr/vice/cache/crash/vmcore.1: No such file or directory.
(kgdb) 

>Fix:

I guess it requires some gross hacks in the kvm_i386 support to go page
table walking?

>Audit-Trail:
>Unformatted: