Re: [Valgrind-users] Empty stack shown by Valgrind

[Austin E. <aus...@gm...>]

Dear All
I am thankful to get such good guidance.

It was shared lib issue.

I had some issue in my code, that was converted to shared lib.

When I did a static linking, I was able to see the trace, and was able to
fix it.

Thank you all again.

Best regards
Austin





On Fri, Jan 2, 2015 at 8:10 PM, John Reiser <jr...@bi...> wrote:

> >> ==28501== 7 bytes in 1 blocks are indirectly lost in loss record 33 of
> 152
> >> ==28501==    at 0x402CFC7: malloc (vg_replace_malloc.c:296)
> >> ==28501==    by 0x40AF985: ???
> >> ==28501==    by 0x40AE2A1: ???
>
> As Philippe Waroquiers said in another thread,
> > So, probably you did not compile with debug info (-g option).
>
> While you wait for the re-compile and re-link using -g, it may be possible
> to get some clues by using low-level debugging techniques.  Run the
> program again, and while it is runnning then use a different terminal
> session
> to run
>         cat /proc/PID/maps
> where PID is the process ID; in the reported case PID was 28501.
> Then lookup the addresses to see which module (shared library or main
> program)
> contains each return address such as 0x40AF985, 0x40AE2A1, etc.
> Run "nm" and "readelf --symbols" on the associated modules, then
> interpolate.
>
> Those particular addresses look somewhat unusual.  If they were 16 times
> smaller
> (0x4AF985) then that might well be inside the main program.  If they were
> 16 times larger (0x400AF985) then that often is in some system-supplied
> shared library on a 32-bit i686 running Linux.  But the actual address
> 0x40AF985
> is far away from either usual case.  The original poster said
> > I checked memory leak (using Valgrind 3.10.1 in a Ubuntu 12.04 LTS
> machine)
> but omitted the hardware architecture; please state what it is.
>
> Use a debugger such as gdb to disassemble the code surrounding the return
> addresses,
> such as:        (gdb) x/20i 0x40AF985 - 0x18
> Look for references to global variables, other subroutines, constant
> values, etc.
> In some cases the numerical value of the offset to a pointer may suggest
> the use of a particular data structure.
>
>
>
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