Re: [bug] WARNING: at drivers/char/tty_io.c:1266tty_open+0x1ea/0x388()

From: Ingo Molnar
Date: Tue Jun 16 2009 - 04:50:24 EST



* Alan Cox <alan@xxxxxxxxxxxxxxxxxxx> wrote:

> > > I split the ldisc and tty apart and redid the ldisc locking so its a fair
> > > bet I know what changeset is to blame, will just need to hunt it down a
> > > bit. kmemcheck found one leak case on Friday which I've fixed but not yet
> > > scribbles.
> > >
> > > > c65c9bc: tty: rewrite the ldisc locking
> > >
> > > Almost certainly that one and will investigate on Monday
> >
> > I have applied your patch from yesterday (attached further below for
> > reference) and the SLAB corruption has not triggered - instead i'm
> > now getting this warning, after 96 reboots:
>
> That's progress
>
> > Another test-box has produced this warning too. (Same config and
> > same hw as i sent the details for earlier in this thread.)
> >
> > So there's still something fishy going on.
>
> Are you using a standard udev/fedora setup or something different
> (I know the devtmpfs proposal stuff produces crashes like that one
> all the time which are not seen anywhere else)
>
> And is it reproducable this time - and always 96 ?

It shows up randomly and on multiple systems.

I'm wondering, how long have these patches been in linux-next? Has
no-one reported an easy (or easier) reproducer than a plain bootup
(which really doesnt hit the tty code intentionally hard)?

You should probably also write testcases and stress-tests if you
modify code in this area.

Ingo
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