Re: [Valgrind-users] DESPERATE: Receiving confusing warnings during very short execution phase

[cleca <cle...@un...>]

On Fri, Aug 16, 2013 at 8:33 AM, cleca <clemens.cap@> wrote:

> == PASTE of parts of the complaints ==
>  Invalid read of size 8
> ==19525==    at 0x6E6E2CA: ??? (in
> /home/cap/workspace/kademlia2/libs/libc.so.6)

> You will get better backtraces if you install the "glibc-debuginfo"
> package. (Assuming you are using a Red Hat derivative.) Also, compile
> your application with "-g".

Actually I *did* compile with -g. But your remark had me check the line
above once more...which made me more suspicious and I replaced (my) version
of the libc by the system one (with which valgrind had been compiled).

And VOILA: Problem solved. All messages of valgrind make completely sense
now, whereas they looked absolutely chinese to be before. Probably the
mismatch of C-libraries threw valgrind under the bus. Interesting to see
that valgrind nevertheless was able to produce messages (which, however, did
not make sene to me). Would be nice if valgrind could detect/warn about
that.

THANK YOU very much for you help, it saved my day - I ws really a bit
desperate already.

> You can also try "gdb <my_program>" and then "x/10i 0x6E6E2CA" to see
> what the faulting instruction actually is. If you are lucky, it will
> be an SSE instruction and you can fix the warnings by using the latest
> Valgrind from Subversion and "--partial-loads-ok=yes".

Didn't know this trick and it probably will save my weekend - since I *am*
actually using some SSE-related code fragments which still are awaiting
valgrind-cleanup later today :-)

THANX.



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