Loading shared libraries when cross-debugging a core file

Jan Kratochvil jan.kratochvil@redhat.com
Mon Jan 16 19:02:00 GMT 2012

On Thu, 12 Jan 2012 21:35:53 +0100, Ian Wells wrote:
> I'm trying to pin down an issue I'm having with shared libraries not
> being autoloaded, with no error message, when I cross-debug a ppc
> (Linux / ELF) core file on a cross-debugger compiled on Linux /
> x86_64.

It works for me:
$ d=~/t/core.ppc64;strace -s200 -o /tmp/xj -q ./gdb -nx -ex "set sysroot $d" -ex "set debug-file-directory $d" -ex "file $d/sleep" -ex "core-file $d/core" -ex "info shared"
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Reading symbols from /home/jkratoch/t/core.ppc64/sleep...Reading symbols from /home/jkratoch/t/core.ppc64/sleep.debug...done.
warning: core file may not match specified executable file.
[New LWP 28796]
warning: Can't read pathname for load map: Input/output error.
Core was generated by `sleep 1h '.
Program terminated with signal 11, Segmentation fault.
#0  0x00000080f9234818 in __nanosleep_nocancel () from /home/jkratoch/t/core.ppc64/lib64/libc.so.6
>From                To                  Syms Read   Shared Object Library
0x00000080f919b860  0x00000080f92cc5b0  Yes (*)     /home/jkratoch/t/core.ppc64/lib64/libc.so.6
0x00000080f90e53c0  0x00000080f9104850  Yes (*)     /home/jkratoch/t/core.ppc64/lib64/ld64.so.1
(*): Shared library is missing debugging information.
(gdb) q
$ ls -l $d
total 4900
-rw------- 1 jkratoch jkratoch 2490368 Jan 16 19:17 core
-rwxr-xr-x 1 jkratoch jkratoch  227992 Nov  3 15:03 ld-2.12.so*
lrwxrwxrwx 1 jkratoch jkratoch      10 Jan 16 19:29 ld64.so.1 -> ld-2.12.so*
lrwxrwxrwx 1 jkratoch jkratoch       1 Jan 16 19:32 lib64 -> ./
-rwxr-xr-x 1 jkratoch jkratoch 2178192 Nov  3 15:03 libc-2.12.so*
lrwxrwxrwx 1 jkratoch jkratoch      12 Jan 16 19:29 libc.so.6 -> libc-2.12.so*
-rwxr-xr-x 1 jkratoch jkratoch   34296 Oct  5 15:29 sleep*
-r--r--r-- 1 jkratoch jkratoch   80696 Oct  5 15:29 sleep.debug

> I understand that I will need to point gdb in to the location of the
> library files - this documentation suggests this is the 'sysroot'


> If not with a straightforward answer, can someone
> point me to the code in gdb that identifies which libraries are loaded
> so that I can work out what it's doing?



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