Re: Please add to stable: module: don't unlink the module untilwe've removed all exposure.

[Ben Greear]

On 06/03/2013 08:59 AM, Ben Greear wrote:
> On 06/03/2013 07:17 AM, Joe Lawrence wrote:
>
> > > > Hi Rusty,
> > > >
> > > > I had pointed Ben (offlist) to that bugzilla entry without realizing
> > > > there were other earlier related fixes in this space.  Re-viewing bz-
> > > > 58011, it looks like it was opened against 3.8.12, while Ben and myself
> > > > had encountered module loading problems in versions 3.9 and
> > > > 3.9.[1-3].  I can update the bugzilla entry to add a comment noting commit
> > > > a49b7e82 "kobject: fix kset_find_obj() race with concurrent last
> > > > kobject_put()".
> > > >
> > > > That said, it doesn't appear that commit 944a1fa "module: don't unlink the
> > > > module until we've removed all exposure" has not made it into any stable
> > > > kernel.  On my system, applying this on top of 3.9 resolved a module
> > > > unload/load race that would occasionally occur on boot (two video adapters
> > > > of the same make, the module unloads for whatever reason and I see "module
> > > > is already loaded" and "sysfs: cannot create duplicate filename
> > > > '/module/mgag200'" messages every 5-10% instances.)  I have logs if you
> > > > were interested in these warnings/crashes.
>
> It at least works around the problem for me as well.  But, a more rare
> migration/[0-3] (I think) related lockup still exists in 3.9.4 for me,
> so I will also try applying that other kobject patch and continue testing
> today...

Well, that other kobject patch is already in 3.9.4, so I think it's still
a good idea to include the
"module: don't unlink the module until we've removed all exposure."
patch in stable.  I have a decent test case to reproduce the crash, so if someone
wants me to test other patches instead, then I will do so.

Thanks,
Ben

--
Ben Greear <greearb@xxxxxxxxxxxxxxx>
Candela Technologies Inc  http://www.candelatech.com

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/