Re: [PATCH 4.4 02/96] s390/runtime instrumention: fix possible memory corruption

[Heiko Carstens]

On Tue, Dec 05, 2017 at 06:08:47PM +0100, Greg Kroah-Hartman wrote:
> On Tue, Dec 05, 2017 at 05:02:32PM +0000, Ben Hutchings wrote:
> > On Tue, 2017-11-28 at 11:22 +0100, Greg Kroah-Hartman wrote:
> > > 4.4-stable review patch.  If anyone has any objections, please let me know.
> > > 
> > > ------------------
> > > 
> > > From: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
> > > 
> > > commit d6e646ad7cfa7034d280459b2b2546288f247144 upstream.
> > [...]
> > > --- a/arch/s390/kernel/runtime_instr.c
> > > +++ b/arch/s390/kernel/runtime_instr.c
> > > @@ -47,11 +47,13 @@ void exit_thread_runtime_instr(void)
> > >  {
> > >  	struct task_struct *task = current;
> > >  
> > > +	preempt_disable();
> > >  	if (!task->thread.ri_cb)
> > >  		return;
> > 
> > This return path now leaves preemption disabled.  This seems to have
> > been fixed upstream by commit 8d9047f8b967 "s390/runtime
> > instrumentation: simplify task exit handling".
> 
> "simplify" doesn't seem to imply "fixes a bug" :)

Indeed ;) That where two subsequent patches, but incorrectly split by me...

> Heiko, should I also queue this patch up?

Yes, please.

> thanks Ben for the review.

Thanks from me as well!