Why I can't disassemble this user space address?

Question

Dump of assembler code for function foo@plt:
0x0000000000400528 <foo@plt+0>: jmpq   *0x2004d2(%rip)        # 0x600a00 <_GLOBAL_OFFSET_TABLE_+40>
0x000000000040052e <foo@plt+6>: pushq  $0x2
0x0000000000400533 <foo@plt+11>:    jmpq   0x4004f8
(gdb) disas 0x4004f8
No function contains specified address.

I knwo 0x4004f8 is the entry point of procedure linkage table,but why I can't disas it?

score 6 · Accepted Answer · edited May 23 '17 at 11:58

6

disas with one address needs to find the function the address is contained within to know how much to disassemble.

Either with disas with two arguments, or x/i.

Also see: How can I force GDB to disassemble?

edited May 23 '17 at 11:58

Community

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answered Jun 10 '11 at 12:50

Douglas Leeder

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the plt is used to resolve dynamically linked `function`,what about dynamic `variable`? – compile-fan Jun 10 '11 at 12:54
Also,how can `0x4004f8` not be contained in any function? There should always be a function that wraps this address IMO... – compile-fan Jun 10 '11 at 13:01
0x4004f8 is probably in a function, but gdb can't understand it for some reason. Give gdb a range and have done with it? – Douglas Leeder Jun 10 '11 at 13:03
Yes it works ,but I want to investigate more about how shared library works(especially how variables in it are referenced),do you want a separate thread for this ? :) – compile-fan Jun 10 '11 at 13:06
Yes, that sounds like a different question to me. – Douglas Leeder Jun 10 '11 at 17:54

Why I can't disassemble this user space address?

1 Answers1