Messages in this thread | | | Date | Mon, 5 Feb 2007 12:09:28 +0100 | From | Sébastien Dugué <> | Subject | Re: [PATCH -mm 4/7][AIO] - Make good_sigevent() non-static |
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Hi Oleg,
thanks for your comments.
On Fri, 2 Feb 2007 21:00:39 +0300 Oleg Nesterov <oleg@tv-sign.ru> wrote:
> On 02/01, S?bastien Dugu? wrote: > > > > +struct task_struct * sigevent_find_task(sigevent_t * event) > > +{ > > + struct task_struct *task = NULL; > > + > > + if (event->sigev_signo <= 0 || event->sigev_signo > SIGRTMAX) > > + return NULL; > > + > > + if ((event->sigev_notify & SIGEV_THREAD_ID ) == SIGEV_THREAD_ID) { > > + task = find_task_by_pid(event->sigev_notify_thread_id); > > + > > + if (!task || task->tgid != current->tgid) > > + task = NULL; > > + } else if (event->sigev_notify == SIGEV_SIGNAL) > > + task = current->group_leader; > > + > > + return task; > > +} > > I am afraid this is still not right. Consider > > ->sigev_notify == SIGEV_THREAD_ID | RANDOM_BIT > > Now, the second "if (SIGEV_THREAD_ID)" returns a valid task. However, > > really_put_req: > > if (notify == SIGEV_THREAD_ID || notify == SIGEV_SIGNAL) > put_task_struct(); > > doesn't work, so we have task_struct leak.
Right, I'll revert back to the old code with cleanups.
> > Worse, this breaks posix-timers. Note that posix-timers allow SIGEV_NONE, > the timer is not queued in that case, we shouldn't do ->sigev_signo check. > This means that aio should check SIGEV_NONE itself. > > Also, it is critical for posix-timers that SIGEV_THREAD_ID doesn't come > with another bit (like in the example below), note the code like > > if (sigev_notify == (SIGEV_SIGNAL|SIGEV_THREAD_ID)) > ... > > IOW: good_sigevent() in its current form is very cryptic, and it _really_ > needs a cleanup, but we should not change its behaviour.
Yep. I must admit that I didn't pay enough attention to this 10-liner, but in the end it rightfully backfired on me.
> > Apart from this, I don't see other problems in the signal related code in > this series. > > Oleg. >
Thanks again for your review.
Sébastien. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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