Re: [PATCH] fix bad locking in drivers/base/driver.c

[Thomas Gleixner <tglx@linutronix.de>]

On Tue, 2005-01-25 at 11:19 -0800, Greg KH wrote:
> On Tue, Jan 25, 2005 at 08:27:15AM -0800, Linus Torvalds wrote:
> > 
> > 
> > Hmm.. I certainly like the "use completions" patch, since it makes it a
> > lot more obvious what is going on (and it is what completions were
> > designed for).
> > 
> > However, since it does change semantics very subtly: if you call
> > "driver_unregister()" twice (which is wrong, but looking at the code it
> > looks like it would just silently have worked), the old code would just
> > ignore it. The new code will block on the second one.
> > 
> > Now, I don't mind the blocking (it's a bug to call it twice, and blocking
> > should even give a nice callback when you do the "show tasks"  sysrq, so
> > it's a good way to _find_ the bug), but together with Mike's comment about
> > "Compile-tested only", I'd really like somebody (Greg?) to say "trying to
> > doubly remove the driver is so illegal that we don't care, and btw, I
> > tested it and it's all ok".
> 
> I will add it to my queue of patches for the driver core, and test it
> out accordingly before trying it out in the -mm tree for a while.
> 

Exactly the same patch is around since 2004-10-20.

http://marc.theaimsgroup.com/?l=linux-kernel&m=109836020930855&w=2

It never showed any problems and I have it in my kernels since then.
Also Ingo's RT patches have it since October. 

tglx