Messages in this thread | | | Date | Sun, 25 Dec 2005 17:02:33 +0100 | From | Manfred Spraul <> | Subject | Re: [PATCH] - Fix memory ordering problem in wake_futex() |
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Again replying to myself, sorry:
Jack Steiner wrote:
>On Fri, Dec 23, 2005 at 11:23:11PM +0100, Manfred Spraul wrote: > > >>Bad race. >>Unfortuantely the scenario that you describe is quite frequent: >>- autoremove_wake_function() >> >> Not a bug, but for very subtile reasons: There are no writes to the wait_queue structure except the list_del_init(), and for list_del_init() no memory barriers are required because finish_wait() uses list_empty_careful(), i.e. the spin_lock() is only bypassed if both write operations from list_del_init() have completed.
>>- ipc/sem.c (search for IN_WAKEUP) >> >> fixed in -rc7.
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