Messages in this thread | | | Date | Wed, 30 Jul 2003 10:28:48 +0200 | From | Andrea Arcangeli <> | Subject | Re: PATCH: Race in 2.6.0-test2 timer code |
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On Wed, Jul 30, 2003 at 09:34:40AM +0200, Ingo Molnar wrote: > > On Wed, 30 Jul 2003, Andrea Arcangeli wrote: > > > The thing triggered simply by running setitimer in one function, while > > the it_real_fn was running in the other cpu. I don't see how 2.6 can > > have fixed this, it_real_fun can still trivially call add_timer while > > you run inside do_setitimer in 2.6 too. [...] > > This is not a race that can happen. itimer does this: > > del_timer_sync(); > add_timer(); > > how can the add_timer() still happen while it_real_fn is still running on > another CPU?
it's not add_timer against add_timer in this case, it's del_timer_sync against add_timer.
cpu0 cpu1 ------------ --------------------
do_setitimer it_real_fn del_timer_sync add_timer -> crash
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