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gdb package

  1. Bug #111869
  2. Comment #10

Comment 10 for bug 111869

Revision history for this message
In , Mmeeks (mmeeks) wrote :

So - to try to expand and elaborate when you write the above what I hear is:

   "yes, we could provide a much more useful stack trace to the poor person
    trying to debug something - but we're not going to: because we want
    to show something else much less useful" ;-)

or do I mistake things ? ;-) valgrind can provide a useful trace for a poor hacker trying to find what went wrong and where; but gdb is committed to not do so ? just for reference since we have the valgrind trace above - lets see what gcc does when we get the same segv trapped:

Program received signal SIGSEGV, Segmentation fault.
0x08048584 in ?? ()
(gdb) bt
#0 0x08048584 in ?? ()
#1 0x080486b0 in _IO_stdin_used ()
#2 0x00000001 in ?? ()
#3 0x00000025 in ?? ()
#4 0xb7fec560 in ?? () from /lib/libc.so.6
#5 0x00000027 in ?? ()
#6 0xb7eac6c0 in ?? ()
#7 0xbf930898 in ?? ()
#8 0x080485b0 in ?? ()
#9 0x00000001 in ?? ()
#10 0x00000003 in ?? ()
#11 0xbf9308b8 in ?? ()
#12 0xb80134ac in trace_two (fn=0x1) at two.c:8
Backtrace stopped: previous frame inner to this frame (corrupt stack?)

Are you suggesting that this is a more useful view than:

==21438== at 0x8048584: (within /home/michael/gdb-testcase/a.out)
==21438== by 0x80485AF: (within /home/michael/gdb-testcase/a.out)
==21438== by 0x40294AB: trace_two (two.c:8)
==21438== by 0x80485C3: (within /home/michael/gdb-testcase/a.out)
==21438== by 0x80485DB: (within /home/michael/gdb-testcase/a.out)
==21438== by 0x40655F5: (below main) (libc-start.c:220)

[ though I guess, due to some fluke of parameters passed (no 0's) we managed at least to get nice line number information for trace_two ].

If this more useful, what is it ? :-) [ I assume it's just an unwind of the stack, frame by frame printed in hex with some guesses as to function addresses - until we hit a NULL - but how useful is that really honestly ? vs. being able to tell what was called from where ].

Or - are you suggesting that we shouldn't strip any of our binaries as we ship them - so we can can get stack traces when things fail ? or ...