On 11 Feb 2003, Nathan J. Williams wrote:

> Karl Janmar <karlj@mdstud.chalmers.se> writes:
>
> > Here is some more data:
> > (gdb) info thread
> >   5 Thread 0  0x485700f7 in poll () from /usr/lib/libc.so.12
> >   4 Thread 21  0x4857008b in select () from /usr/lib/libc.so.12
> >   3 Thread 22  0x4857013f in nanosleep () from /usr/lib/libc.so.12
> >   2 Thread 69  0x4857013f in nanosleep () from /usr/lib/libc.so.12
> > * 1 Thread 70  0x482e5f65 in write () from /usr/lib/libpthread.so.0
> > (gdb) thread ex all
> > 0x48fc0000: thread   70 in kernel
> > 0x48f80000: thread   69 in kernel
> > 0x48f40000: thread   22 in kernel
> > 0x48b40000: thread   21 in kernel
> > 0xbfbc0000: thread    0 in kernel
>
> OK. All the userland threads are sleeping in the kernel (actually,
> they probably woke up from their original system call, tried to
> deliver a UNBLOCKED upcall, and are sleeping waiting for a stack to
> become avaliable). The fact that there's still a thread consuming CPU
> probably means another bug in libpthread.. possibly in the
> resolve_locks dance in pthread_sa.c; more likely a spinlock count is
> going negative somewhere, which will confuse the resolve_locks algorithm.
>
> This is i386, right (guessing from the address of thread 0)? I'll send
> you some additional debugging tools in a little bit.
>
> > If I get the point the sa_nstacks is running out because the stacks aren't
> > recycle properly, so someware in kern_sa.c it "leaks stacks"?
>
> That's one possibility... more likely, though, is that the userland
> code is wedged in a state where it doesn't get around to recycling the
> used stacks back to the kernel.
>
>         - Nathan
>


Okej, after looking in sa_getcachelwp():

what is 	/* XXX lock sadata */
and 	/* XXX unlock */
maybe this has something to do with the problem??
a race condition after all??

Regards, Karl.