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

[Frederic Weisbecker]

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@xxxxxxxxxx>
> > Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
> > Cc: Frédéric Weisbecker <fweisbec@xxxxxxxxx>
> > Cc: Paul McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
> > Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
> 
> Looks like the RCU entry/exit stuff is properly accounted for, so:
> 
> Acked-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>

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.
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