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/lib64/ld64.so.1 not being added to target sections list on ppc64
- From: Paul Gilliam <gilliam at us dot ibm dot com>
- To: gdb at sourceware dot org
- Date: Mon, 5 Feb 2007 17:33:21 -0800
- Subject: /lib64/ld64.so.1 not being added to target sections list on ppc64
I am tracking down a bug where the inf. gets a segfault when the user sets
a pointer variable to point to a string:
(gdb) set var ptr1="foo"
gdb "calls" 'malloc' in the inf. It gets a function pointer to 'malloc',
but fails to convert it to a function address because none of the sections
of the object file with the .opd section corresponding to the function
pointer are loaded into the target sections table. So
'Convert_Function_Pointer_To_Address' (or whatever it's called) just
returns the function pointer. When gdb tries to 'call' that
(non-executable) address, a segfault happens.
The .opd section corresponding to the function pointer is in the
/lib64/ld64.so.1 object file.
But wait, there's more!
There is another table of sections that is used when the gdb command 'info
symbol' is used. If I go:
(gdb) p &malloc
(gdb) info symbol $1
gdb responds 'malloc is in the .opd section'
I don't understand:
1) why are there two section tables?
2) why aren't sections from /lib64/ld64.so.1 being loaded into the target
sections table?
3) why is the function pointer for 'malloc' pointing to a plt in the
/lib64/ld64.so object and not one in the main executable?
I welcome any insight any of you might have.
Thanks in advance,
-=# Paul Gilliam #=-
PS: I have changed jobs and don't work on GDB any more, but this one bug
followed me to my new job.