Date: Fri, 18 Oct 96 13:12:05 +0200 From: garyj@frt.dec.com To: Fred Condo <fred@lightside.net> Cc: questions@freebsd.org Subject: Re: gdb can't access address Message-ID: <9610181112.AA16475@cssmuc.frt.dec.com> In-Reply-To: Message from Fred Condo <fred@lightside.net> of Thu, 17 Oct 96 18:08:34 PDT.
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fred@lightside.net writes: > I've been trying to help track down the SEGV bug in Apache. To that end, > I've tried to backtrace the core dump using gdb. When I do that, I can get > a backtrace without symbols, but it can't do it with the symbols turned on. > Here's an example: > > Core was generated by `httpd-g'. > Program terminated with signal 6, Abort trap. > #0 0x8091ee5 in ?? () > (gdb) bt > #0 0x8091ee5 in ?? () > #1 0x3e88 in ?? () > #2 0xefbfe13c in ?? () > #3 0xc7a9 in ?? () > #4 0xcb99 in ?? () > #5 0x4941 in ?? () > #6 0x4b2d in ?? () > #7 0x5127 in ?? () > #8 0x5419 in ?? () > #9 0x10d3 in ?? () > (gdb) file httpd-g > Reading symbols from httpd-g...done. > (gdb) bt > #0 0x8091ee5 in end () > Cannot access memory at address 0x366c0. > > After loading the symbols, it can only show me the innermost stack frame :( > > Any suggestions would be appreciated. This is under FBSD 2.1.0R and > whatever gcc comes with that (2.6.3, I think). > > I assume that httpd-g was compiled with -g ? gdb can't resolve the shared libraries from a core dump since they aren't mapped. Unless the libraries were also compiled with -g you won't get very meaningful info when gdb hits a library routine, of course. Try doing the following: gdb httpd-g b main run <-- should load & map the shared libs core-file httpd-g.core after that you should be able to get a stack trace. This used to work. --- Gary Jennejohn (work) gjennejohn@frt.dec.com (home) Gary.Jennejohn@munich.netsurf.de (play) gj@freebsd.org
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