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User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.8) Gecko/20060126 Fedora/1.5-5 Firefox/1.5

Description of problem:
When debugging a 32-bit executable on x86_64, gdb does not allow examining the stack if pointed to by a non-$esp register.  For example,
-----foo.S
_start: .globl _start
        nop
        int3
        movl %esp,%ebx
        int3  # examining memory from $ebx fails, from $esp succeeds
        nop
        nop
-----
$ gcc -m32 -o foo -nostartfiles -nostdlib foo.S
$ gdb foo


Version-Release number of selected component (if applicable):
gdb-6.3.0.0-1.98.2

How reproducible:
Always

Steps to Reproduce:
1. Build and debug the 32-bit test program in the Description.
2. Examine memory from $esp then from $ebx with the same value.
3.
  

Actual Results:  (gdb) run
Starting program: /home/jreiser/foo
Reading symbols from shared object read from target memory...(no debugging symbols found)...done.
Loaded system supplied DSO at 0xffffe000

Program received signal SIGTRAP, Trace/breakpoint trap.
0x08048076 in _start ()
(gdb) x/i $pc
0x8048076 <_start+2>:   mov    %esp,%ebx
(gdb) stepi
0x08048078 in _start ()
(gdb) x/x $esp
0xffffce70:     0x00000001
(gdb) x/x $ebx
0xffffce70:     Cannot access memory at address 0xffffce70
(gdb) x/x 0xffffce70
0xffffce70:     0x00000001


Expected Results:  "x/x $ebx" should have succeeded, too, when %ebx has the same value as %esp and examining from $esp works.


Additional info:

Workaround apears to be: print the register, then use the contents as a literal address to examine.