Re: Filesystem tests crashing host

[Mindaugas Rasiukevicius <rmind%netbsd.org@localhost>]

Juergen Hannken-Illjes <hannken%eis.cs.tu-bs.de@localhost> wrote:
> I added some instrumentation too. With a printf from ksem_sysinit(),
> ksem_sysfini() and do_ksem_init()/do_ksem_open() I get:
> 
>       fs/nfs/t_mountd (91/400): 1 test cases
>           mountdhup:
>       ksem_sysinit ops 0xcb0d4bc0
>       fp 0xcaf91780 ops 0xcb0d4bc0
>       ksem_sysfini ops 0xcb0d4bc0
>       uvm_fault(0xc0b0f380, 0xcb0d4000, 1) -> 0xe
> 
> Backtrace:
> 
>       closef(caf91780, ...) <== the file with the ksem above!
>       fd_free()
>       exit1()
>       sigexit()
>       postsig()
>       lwp_userret()
>       syscall()
> 
> The fault address is the page containing the ops vector of the now
> unloaded ksem module -- page fault -- boom.

Thanks!  So it happens because somebody unloads the ksem module.  That is
an interesting bug (which makes me think that there is a potential for it
in other modularised subsystems).

Will fix it shortly.

-- 
Mindaugas