Re: [Valgrind-users] Valgrind on MIPS Reports Zero Heap Usage

[Woodrow B. <wjb...@nc...>]

Hello Sir,

Thank you for the help. I'm not entirely sure whether malloc is provided by
libc.so.0 or by ld-uClibc.so.0, so I've executed the requested command
against both. I'm afraid I don't know how to interpret the output, but I've
included it below:

    $ readelf -d lib/libc.so.0 | grep SONAME
     0x0000000e (SONAME)                     Library soname: [libc.so.0]
    $ readelf -d lib/ld-uClibc.so.0 | grep SONAME
     0x0000000e (SONAME)                     Library soname:
[ld-uClibc.so.0]

I've also done a readelf against the executable which I am attempting to
test. I am including below a few lines of that output which may be useful.

    Dynamic section
      Tag        Type                         Name/Value
     0x00000001 (NEEDED)                     Shared library: [libgcc_s.so.1]
     0x00000001 (NEEDED)                     Shared library: [libc.so.0]
     0x0000000f (RPATH)                      Library rpath: [//lib]

    Symbol table '.dynsym'
       Num:    Value  Size Type    Bind   Vis      Ndx Name
        27: 00404a40     0 FUNC    GLOBAL DEFAULT  UND free
        97: 00404690     0 FUNC    GLOBAL DEFAULT  UND malloc

Finally, as requested, I've run Valgrind with the debugging options against
a very simple application with malloc (I ran it against the memory leak
test program from the Valgrind FAQ). The output is attached.


 - Woodrow Barlow

On Thu, Oct 9, 2014 at 5:54 PM, Philippe Waroquiers <
phi...@sk...> wrote:

> On Wed, 2014-10-08 at 14:46 -0400, Woodrow Barlow wrote:
> > Basically, Valgrind doesn't detect any heap usage even though I've
> > used the heap. Why might this be? Are any of my assumptions (below)
> > wrong?
> The 3 known causes are:
> A statically linked
> B LD_PRELOAD not supported/not configured
> C linked with a library whose soname does not match the expected name
>
> The tests you have done exclude causes A and B.
> To exclude C, can you check the soname of the library that provides
> malloc ?
> I.e. something like:
>   readelf -d /lib/libc.so.6 | grep SONAME
> giving
>   0x0000000e (SONAME)                     Library soname: [libc.so.6]
>
> The resulting soname should match the default expected soname pattern,
> i.e. on a linux, it is expected to match  libc.so*
> If the soname of your lib does not match the above, then you can use
>     --soname-synonyms=somalloc=xxxxxxxx
> where xxxxxxxx is something which matches your soname
>
> Assuming the above is not the problem, then something else/unknown is
> happening.
>
> Can you then run a small test program dynamically linked, that does
> a malloc call
> and use valgrind options
>    -v -v -v -d -d -d --trace-malloc=yes --trace-redir=yes
> and send the resulting log file?
> If the file is big, you can compress it, and send it only to me.
>
> Hoping this helps
>
> Philippe
>
>
>