[Ltrace-devel] [PATCH 0/1] Attempt to fix libdl tracing when attaching to PIDs

[Petr Machata]

Joe Damato <ice799 at gmail.com> writes:

> On Tue, Mar 19, 2013 at 6:25 PM, Petr Machata <pmachata at redhat.com> wrote:
>> Joe Damato <ice799 at gmail.com> writes:
>>
>>> joe at ubuntu:~/code/ltrace$ /tmp/test/usr/local/bin/ltrace -e* -p 2821
>>> libm.so.6->(0x7fff07366f90, 0x7fff07366f90, 0, -1)                                                      = 0x7f0384fe06a0
>>> libdl.so.2->__cxa_finalize(0x7f038582f078, 0, 0xffffffff, 0x7f038582ed50)                               = 0x7f0385627350
>>> libm.so.6->(0x7f038526c0c0, 0, 0, 3)                                                                    = 0x7f0385627350
>>> +++ exited (status 0) +++
>>
> Appears that my libm does go through the PLT for 2 things:
>
> 0000000000025ca0 <acos>:
> [...]
>    25cb6:       e9 f5 f7 fd ff          jmpq   54b0 <*ABS*+0x10590 at plt>
> [...]
>    25cd7:       e9 64 fc fd ff          jmpq   5940 <*ABS*+0x1fc30 at plt+0x3e0>

In that case we are missing one PLT call in your output.  Tracing both
-x acos at libm\* and -e\* would help us indicate what the exact order of
operations is.

Would you mind sending me your libm.so binary privately?  Chances are
I'll be able co reproduce the problem with it, distill a test case, etc.

Thanks,
PM