Re: GDB doesnot catches segmentation fault

[Phil Muldoon <pmuldoon at redhat dot com>]

Mahmood Naderan <nt_mahmood@yahoo.com> writes:

> Hi
> I have attached a PID to gdb. Although the code crashed with segmentation fault, but gdb ignores that and I am not able to view backtrace.

> 0x0000000000447bfb in Event::initialized (this=0x41ec648) at build/ALPHA_FS/sim/eventq.hh:84
> 84ÂÂÂÂÂÂÂÂÂ initialized() const
> (gdb) c
> Continuing.
> Segmentation fault
> mahmood@mpc:~$

This looks like GDB crashed with a segmentation fault.

There is not enough information to work with here.  There are two things
you could try: A newer GDB, the problem might already have been
fixed. Or, submit a backtrace for GDB.

If you have debug information installed for GDB you can do this.  I am
not sure of the method for installing debug information for installed
packages with Ubuntu.  But assuming you do have them:

Type: 

ulimit -c unlimited

in the terminal where you will launch GDB  (This will allow core-files
to be generated).

Attach GDB to the program (as you did above) and replicate the scenario
to crash GDB.

Then:

gdb gdb --core=yourcore.pid

Where "youcore.pid" is the core-file that GDB generated on crash.

Then type "bt" into GDB.  This will produce a backtrace of the crashing
GDB process.

Then create a bug at: 

http://sourceware.org/bugzilla/ 

for gdb, and paste the "bt" output.  Also include any supplemental
information you think is useful.

Cheers,

Phil