Re: kernel config question

[David Woodhouse <dwmw2 infradead org>]

On Wed, 2007-03-28 at 09:35 -0700, Greg KH wrote:
> On Wed, Mar 28, 2007 at 09:29:03AM +0100, David Woodhouse wrote:
> > On Mon, 2007-03-19 at 11:56 -0400, Bill Nottingham wrote:
> > > > But changes to environment variables in the hotplug script >
> > > invocations shouldn't hurt, right?
> > > 
> > > No, but that's not the reason we have DEPRECATED on. 
> > 
> > OK, thanks for the information. I've committed a crappy hack which
> > disables those extra environment variables (the ones which
> > CONFIG_SYSFS_DEPRECATED enables). It's those which were crashing the
> > kernel.
> 
> Huh?  Care to point me to more information about this?

https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=227893 (and a bunch
of dupes), and also in your inbox on 19th March, with subject
"sysfs use-after-free in 2.6.21-rc"

> > It's not the _correct_ fix, because the crash is just a _symptom_ of the
> > fact that somewhere in that sysfs mess we have a pointer to freed
> > memory. But at least it prevents the kernel from crashing, which is
> > probably a good thing in the short term.
> 
> What kernel version are we talking about here?

Fedora rawhide -- basically Linus' HEAD. We've been seeing it ever since
we enabled CONFIG_SYSFS_DEPRECATED about 2.6.20-rc6-git1.

For the moment I've committed a hack to disable the extra variables in
uevents, since that wasn't why we turned SYSFS_DEPRECATED on again
anyway. It's not a fix though.

-- 
dwmw2