[uml-user] Debugging inside UML

[Kevin C. <co...@us...>]

Greetings,

I was wondering if anyone has experienced any problems when trying to debug 
user-space programs inside UML? I've looked through the UML documentation and 
through the recent mail archives, and haven't found anything concerning this. 
For reference, I am running this on UML 2.4.12-4.

The problem seems quite simple. I have a very simple program (almost "Hello 
world" simple) that I compile with "gcc -g" in my UML session.  If I run the 
program on the command line, everything executes fine. However, if I run this 
program with gdb, the debugger continually traps and segfaults and never 
actually gets to the program code.

Here is the output I get from gdb:

305 root@corry2-uml /test/src/foo> gdb foo
GNU gdb 5.0
Copyright 2000 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 "i386-slackware-linux"...
(gdb) run
Starting program: /test/src/foo/foo

Program received signal SIGTRAP, Trace/breakpoint trap.
0x4000ff6d in ?? ()

(gdb) cont
Continuing.

Program received signal SIGSEGV, Segmentation fault.
0x4000ff6d in ?? ()

(gdb) cont
Continuing.

Program terminated with signal SIGSEGV, Segmentation fault.
The program no longer exists.

(gdb) break main
Breakpoint 1 at 0x8048436: file foo.c, line 7.

(gdb) run
Starting program: /test/src/foo/foo

Program received signal SIGTRAP, Trace/breakpoint trap.
0x4000ff6d in ?? ()
(gdb)


Any program that I try to debug in gdb gives me similar errors, and traps at 
the same address (0x4000ff6d). Does anyone have any ideas, or has anyone seen 
problems like this? Should you be able to debug programs in UML?

TIA
-Kevin Corry