Re: [Valgrind-developers] valgrind and thread-local storage

[Nicholas N. <n.n...@gm...>]

On Mon, Mar 30, 2009 at 8:17 AM, Konstantin Serebryany
<kon...@gm...> wrote:
> Hi valgrind developers,
>
> Does valgrind core do something special about TLS (thread-local storage)?
>
> I've recently discovered a false positive in ThreadSanitizer which is
> caused by TLS.
> Helgrind also emits a race report on the same test case.
> Test:
> //   - Thread1 starts
> //   - Thread1 touches per_thread_global
> //   - Thread1 ends
> //   - Thread2 starts (and there is no happens-before relation between
> it and Thread1)
> //   - Thread2 touches per_thread_global
> // It may happen so that Thread2 will have per_thread_global in the same address
> // as Thread1. Since there is no happens-before relation between threads,
> // ThreadSanitizer reports a race.
> The runable code is in
> http://code.google.com/p/data-race-test/source/browse/trunk/unittest/racecheck_unittest.cc?spec=svn939&r=939#6017
>
> As I understand, the valgrind core handles stack allocation and
> deallocation itself.
> All that tool needs to do is to call VG_(track_new_mem_stack) and similar.
> Is there anything like this for TLS?

No;  it's never come up before...

Nick