Re: [crash] NULL pointer dereference at IP: [<ffffffff812e9ccb>] uart_close+0x2a/0x1e4

[Ingo Molnar <mingo@elte.hu>]

* Linus Torvalds <torvalds@linux-foundation.org> wrote:

> On Mon, 12 Oct 2009, Ingo Molnar wrote:
> > 
> > Note, i have your fix below applied in tip:out-of-tree - it might be 
> > the source of this bug? (If yes then this isnt an .32-rc4 problem.)
> 
> If yes (but you later reported no), it would still be a 32-rc4 
> problem, because that patch got committed as 0b5759c654 ("tty: Avoid 
> dropping ldisc_mutex over hangup tty re-initialization").
> 
> So you shouldn't need it in the out-of-tree branch any more, and you 
> probably just never noticed because it all merged cleanly.

ah, indeed. I'll rebase that branch to clean out any 
went-upstream-already same-content patches. (Ideally that should empty 
it to a large degree.)

> Commit 46d57a449 (which you then bisected to) looks really irritating, 
> since it just renamed variables in annoying ways (ie the old "port" is 
> now "uport", and there's a new "port" that means something else). That 
> thing should have been split up to do the renaming separately, so that 
> a mis-use of "port" would have caused a compile error.
> 
> I'm not seeing anything obvious. Alan obviously found one bug already.

Thanks for checking. I'll try any debug patch from Alan.

	Ingo