Date: Thu, 30 Dec 2010 13:49:18 +0300 From: Lev Serebryakov <lev@FreeBSD.org> To: freebsd-hackers@freebsd.org Subject: PANIC: thread_exit: Last thread exiting on its own. Message-ID: <1385259976.20101230134918@serebryakov.spb.ru>
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Hello, Hackers.
I've got this panic on reboot from geom_raid5. This module has two
threads, each of them finished with kthread_exit(). But it doesn't
panic on every reboot (really, it is first time I got it in row of
many reboots with this module running), so it seems to be some race,
am I right?
I've read code of thread_exit() and I'm not sure I understand it
well. It seems, that EVERY termination of last thread in process
should provoke this panic:
if (p->p_flag & P_HADTHREADS) {
if (p->p_numthreads > 1) {
...
} else {
/*
* The last thread is exiting.. but not through exit()
*/
panic ("thread_exit: Last thread exiting on its own");
}
}
But kthread_exit() has special processing of this situation:
if (curthread->td_proc->p_numthreads =3D=3D 1)
kproc_exit(0); /* never returns */
So, it seems to be some strange race condition in FreeBSD 8-STABLE.
P.S. is this list appropriate for such questions? As far as I
understand, "stable" list is more user-related, not
developer-related, and it is not exactly question about CURRENT.
--=20
// Black Lion AKA Lev Serebryakov <lev@FreeBSD.org>
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