On 08/24, taoyue wrote: > > Oleg Nesterov wrote: > >> > >>collect_signal: sigqueue_free: > >> > >> list_del_init(&first->list); > >> spin_lock_irqsave(lock, flags); > >> > > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > > > >> if (!list_empty(&q->list)) > >> list_del_init(&q->list); > >> spin_unlock_irqrestore(lock, > >> flags); > >> q->flags &= ~SIGQUEUE_PREALLOC; > >> > >> __sigqueue_free(first); __sigqueue_free(q); > >> > > > >collect_signal() is always called under ->siglock which is also taken by > >sigqueue_free(), so this is not possible. > > > >Basically, this patch is the same one-liner I sent you before > > > > http://marc.info/?l=linux-kernel&m=118772206603453&w=2 > > > >(Thanks for the additional testing and report, btw). > > > >P.S. It would be nice to know if this patch solves the problems reported > >by Jeremy, but his email is disabled. > > > >Oleg. > > > > > 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. 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/
