On 08/27, taoyue wrote: > > Oleg Nesterov wrote: > >On 08/24, Sukadev Bhattiprolu wrote: > >>>>> > >>>>I know, using current->sighand->siglock to prevent one sigqueue > >>>>is free twice. I want to know whether it is possible that the two > >>>>function is called in different thread. If that, the spin_lock is > >>>>useless. > >>>> > >>>> > >>>Not sure I understand. Yes, it is possible they are called by 2 different > >>>threads, that is why we had a race. But all threads in the same thread > >>>group have the same ->sighand, and thus the same ->sighand->siglock. > >>> > I has applied the new patch, and start test program last Friday. > So far, the test program has run for three days.
Great, thanks. > In my test program, all threads is created in one process, so they > are in the same thread group. If two thread is not in the same thread > group, they have the different ->sighand->siglock. In this case, the > lock can't prevent the sigqueue object from race condition. If two thread are not in the same thread, they can't access the same SIGQUEUE_PREALLOC sigqueue. That is why sigqueue_free() uses current->sighand. Otherwise, this lock doesn't make any sense, and can't protect list_del(q->list). Oleg. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
