kern/127054: [panic] perl causes panic

[Ed Schouten]

Hello Ben,

* ben wilber <ben at desync.com> wrote:
> On Thu, Sep 04, 2008 at 06:48:29AM +0200, Ed Schouten wrote:
> > > #11 0xffffffff80524e3f in ptsdev_close (fp=0xffffff00057c5808, td=Variable "td" is not available.
> > > )   
> > >     at /usr/src/sys/kern/tty_pts.c:436
> 
> Sorry, I lost my dump again trying to make DDB scripts work.  This is
> yet another new one.

It seems we're dealing with a very obscure case here:

> $4 = {t_mtx = 0xffffff000587c008, t_mtxobj = {lock_object = {
>       lo_name = 0xffffffff808952c6 "tty lock", lo_flags = 16908288, lo_data = 0, 
>       lo_witness = 0x0}, mtx_lock = 6}, t_list = {tqe_next = 0x0, tqe_prev = 0xffffff000530d028}, 
>   t_flags = 1543831584, t_revokecnt = 1, t_inq = {ti_list = {tqh_first = 0x0, 

t_flags shouldn't be this high. Converted to hexadecimal, its value is
0x5c050020. The only valid flags here are TF_GONE|TF_EXCLUDE|TF_ZOMBIE.

> <snip>
>   t_softc = 0xffffff001a30d100, t_dev = 0x0}

t_dev is 0, which means we're tearing down the TTY.

Have you got COMPAT_43TTY enabled in your kernel configuration file? If
so, can you reproduce the panic if COMPAT_43TTY is disabled? I think I
already see where the problem is. And yes, the bug is quite awful.

-- 
 Ed Schouten <ed at 80386.nl>
 WWW: http://80386.nl/
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