cvs commit: src/sys/compat/ndis subr_ntoskrnl.c
Nate Lawson
nate at root.org
Mon Jul 23 19:20:34 UTC 2007
John Baldwin wrote:
> On Sunday 22 July 2007 04:53:28 pm Andrew Thompson wrote:
>> thompsa 2007-07-22 20:53:28 UTC
>>
>> FreeBSD src repository
>>
>> Modified files:
>> sys/compat/ndis subr_ntoskrnl.c
>> Log:
>> ndis will signal the kthread to exit and then sleep on the proc pointer to
>> be woken up by kthread_exit. This is racey and in some cases the kthread
> will
>> exit before ndis gets around to sleep so it will be stuck indefinitely.
> This
>> change reuses the kq_exit variable to indicate that the thread has gone
> and
>> will loop on tsleep with a timeout waiting for it. If the kthread has
> already
>> exited then it will not sleep at all.
>
> As long as you use a lock you are ok. That is:
>
> foo_detach()
> {
>
> mtx_lock(&lock);
> please_die = 1;
> msleep(&proc, &lock, ..., 0);
> mtx_unlock(&lock);
> }
>
> foo_main()
> {
>
> mtx_lock(&lock);
> while (!please_die) {
> do_stuff();
> }
> mtx_unlock(&lock);
> kthread_exit(0);
> }
>
> works fine.
How can foo_detach() acquire the lock to set "please_die" if foo_main()
always holds it? Are you assuming that "do_stuff()" drops the lock
somewhere internally?
-Nate
More information about the cvs-src
mailing list