Re: [PATCH v2] context_tracking: Restore previous state in schedule_user

Frederic Weisbecker
2014-12-04T00:01:43Z

On Wed, Dec 03, 2014 at 03:50:02PM -0800, Paul E. McKenney wrote:
> On Wed, Dec 03, 2014 at 03:37:08PM -0800, Andy Lutomirski wrote:
> > It appears that some SCHEDULE_USER (asm for schedule_user) callers
> > in arch/x86/kernel/entry_64.S are called from RCU kernel context,
> > and schedule_user will return in RCU user context. This causes RCU
> > warnings and possible failures.
> >
> > This is intended to be a minimal fix suitable for 3.18.
> >
> > Reported-and-tested-by: Dave Jones <davej@redhat.com>
> > Cc: Oleg Nesterov <oleg@redhat.com>
> > Cc: Frédéric Weisbecker <fweisbec@gmail.com>
> > Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
> > Signed-off-by: Andy Lutomirski <luto@amacapital.net>
>
> Looks like the RCU entry/exit stuff is properly accounted for, so:
>
> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

Thanks a lot guys!

I'll take the patch. This just won't go for 3.18 I think, the issue
is there since the early days of context tracking.