Re: [Valgrind-developers] drd 2006-12-30

[Bart V. A. <bar...@gm...>]

On 1/1/07, Duncan Sands <bal...@fr...> wrote:
> Hi Bart,
>
> > A new drd version is available at
> > http://home.euphonynet.be/bvassche/valgrind/valgrind-6458-drd-2006-12-30.patch.gz.
>
> thanks for doing this.  I gave it a whirl and it seems to work fine.  However it
> reported a false positive: two threads, thread 1 and thread 2, write to the same
> memory location in an unsynchronized way, but they write *the same value* to it.
> Thread 1 then reads the value, which may have last been written by thread 1 or
> thread 2.  This gets reported as a race, even though there is no race since the
> value read is independent of the order in which the threads wrote it:

It wouldn't be easy to recognize this pattern in the drd tool. Is it
possible to generate a suppression pattern with Valgrind's option
--gen-suppressions=all ? If it is the conflicting accesses are
triggered by the Ada implementation, I can add them to the default drd
suppression file.

Bart.