Re: [PATCH 1/3] ser_gigaset: fix up NULL checks

> Should we backport this all the way to v2.6.32 (currently the oldest
> stable tree)?

We need to be able to explain how the case being tested can occur, then
explain the situation in which it actually prevents a race condition.

If nobody can do that then it shouldn't be backported because its change
without value and just risk. 

The right fix as far as I can see is to remove the tests although
WARN_ON() combined with your tty->ops change might be safer.

> It's pretty obvious that this should have been part of commit
>  f34d7a5b7010 ("tty: The big operations rework"). That being said, these

It ahould probably have been fixed around the same time or in one of the
tty locking reviews, but drivers/isdn and net/irda weren't traditionally
part of the general tty maintenance but handled separately/

> test puzzle me. It's not obvious why they're needed. Ie, can the null
> dereferences they try to catch really happen? But I can try to figure
> out that in the future, if I ever feel the urge to do so. Anyhow:
> 
> Acked-by: Paul Bolle <[email protected]>

Nacked-by: Alan Cox <[email protected]>