DragonFly bugs List (threaded) for 2008-01
DragonFly BSD
DragonFly bugs List (threaded) for 2008-01
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Re: [issue920] Incomplete backtrace in gdb


From: "Simon 'corecode' Schubert" <corecode@xxxxxxxxxxxx>
Date: Wed, 16 Jan 2008 22:10:40 +0100

Simon 'corecode' Schubert wrote:
With current HEAD and gdb 6.7.1 I can't get complete backtraces any more. Example from Xorg.core:

could you supply the core and binary for debugging?

I received both from hasso privately.


I have to say that gdb is not really at fault here. Thorough investigation revealed:

#7 0x0807b766 in ?? ()

This function really doesn't exist. Well, it does, but it doesn't have a visible symbol. Because of this, gdb can't analyze the function prologue and thus assumes that there is nothing on the stack - of course this is wrong. We could change gdb to assume that there is always a stack frame and this way it could work better for this case.

Previous gdb versions mistakenly assumed a different calling function and happily unwound the prologue of the wrong function. This led to better backtraces, but possibly wrong ones.

cheers
  simon

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