Re: [NEW PATCH] POSIX timers for 2.3.26

Alan Cox (alan@lxorguk.ukuu.org.uk)
Tue, 9 Nov 1999 23:15:25 +0000 (GMT)


>
> + memset (&tes, 0, sizeof(tes));
> + if (get_user (tes.sigev_value.sival_int, &timer_event_spec->sigev_value.sival_int) ||
> + __get_user (tes.sigev_signo, &timer_event_spec->sigev_signo) ||

You cant do that one. Suppose the object is across a page boundary. You need
to check the address range first then use __get_user. In fact its probably
faster to memcpy the object from user into L1 cache then use it

> +asmlinkage int sys_timer_create(clockid_t which_clock,
> + struct sigevent *timer_event_spec,
> + timer_t *created_timer_id)

This one has races I think

> + timers = current->posix_timers = itimer_struct_new();

What if two threads sharing timers execute this at the same time. I suspect
you need to guard this with the tasklist lock perhaps ?

Also consider exec and a setuid program getting started with suprise signals
pending. I suspect execve needs to kill these timers ?

Alan

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