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

[Linus Torvalds <torvalds@linux-foundation.org>]

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.

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.

		Linus