Re: 2.6.13-rc5-mm1: oops when starting nscd on AMD64

Alexander Nyberg
2005-08-08T10:38:40Z

> > > I don't think it was supposed to do that.
> > >
> > > Quite possibly it's something to do with the new debugging code - could you
> > > please take a copy of the offending config, send it over and then try
> > > removing debug options, see if the crash goes away? CONFIG_DEBUG_PREEMPT
> > > would be the first to try..
> >
> > The (offending) .config is attached and here's what happens without CONFIG_DEBUG_PREEMPT
> > (the other debug options being unchanged):
>
> Yes, my emt64 machine keels over with your .config too. Maybe it's due to
> CONFIG_SMP=n, not sure.
>
> Bisection searching shows that the bug was introduced by
> slab-leak-detector-give-longer-traces.patch.
>

I was afraid it was when I first saw it but I couldn't reproduce (and
still can't).

> Call Trace:<ffffffff801a17bb>{sys_epoll_create+568} <ffffffff8018b1f7>{vfs_readdir+167}
> <ffffffff80231000>{add_preempt_count+93} <ffffffff8010e8fa>{system_call+126}
>

For some reason your compilers inline heavier than mine do, which makes
this:

kmem_cache_alloc
sys_epoll_create (__builtin_return_address(0))
system_call (__builtin_return_address(1))
(__builtin_return_address(2))

and off the stack we go...

I guess it was naive to even try to use this for more than the first
caller, sorry. Please throw that thing away and I'll do some backtracing
similar to CONFIG_PAGE_OWNER