On Tuesday 02 November 2004 06:27 pm, David Xu wrote:
> John Baldwin wrote:
> >On Monday 01 November 2004 06:04 pm, David Xu wrote:
> >>Not every important, I think I have another very important history
> >>bug in hand, did you get my "fix famous libpthread conditional
> >>variable race condition" mail ? :-)
> >
> >Oooo, can I test it please? We are still having problems with mono on
> > HEAD here at work. I tried merging the changes in uthread_cond.c 1.32 to
> > libpthread but that seemed to make it worse. The problems seem to be
> > that a signal handler is being run when the SYNCQ sflag is set (but the
> > thread is not on a cv or a mutex queue), and the handler calls sem_post()
> > which is supposed to be signal safe. sem_post() tries to lock a mutex
> > and then bombs with the assertion failure.
>
> You can try:
> http://people.freebsd.org/~davidxu/kse/thr_cond.c.diff
>
> But it was not designed to fix the problem you have seen. :-)
This looks like it's trying to fix the same problem as uthread_cond.c rev 1.32
in libc_r but in a different way. The fix for libc_r was to always unlock
the mutex instead of trying to keep it locked in some cases. The kernel cv
code works like this as well. I have a patch that ports 1.32 of
uthread_cond.c to thr_cond.c if you are interested.
--
John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve" = http://www.FreeBSD.org