Re: [PATCH] ugen detach race

On Wednesday 05 April 2006 04:44, Anish Mistry wrote:
> On Wednesday 05 April 2006 03:53, Anish Mistry wrote:
> > 	While working on getting hplip ported I ran across a race
> > condition in the ugen code that causes a crash.  The following
> > patch fixes a problem where read, write, and ioctl can be called
> > during a detach since sc_dying isn't checked before bumping the
> > reference count. This puts the sc_dying check before the *_do_*
> > functions are called. This includes the patch from usb/81308 to
> > prevent polling on the control endpoint.  As well as a few NULL
> > pointer checks from NetBSD. This patch is applicable to RELENG_6.
>
> And CURRENT.
>
> > http://am-productions.biz/docs/ugen-detach-race.patch
> >
> > This doesn't fix the case where an application has a read/write
> > pending and then detach is called.  In this case destroy_devl
> > will just keep looping until the read/write completes.
I've updated the patch.  It now includes the fix for the panic on 
detach when a process has a device open when a detach occurs.  ugen 
now no longer waits for the process to close the connection and just 
cuts it off.
Applies to RELENG_6 and CURRENT.

http://am-productions.biz/docs/ugen-detach-race.patch

The patch should fix usb/93949 too.
This seems to fix all the panics I'm seeing with the ugen device.  It 
would be nice if this could make it into 6.1.

-- 
Anish Mistry