Re: [PATCH stable] tick/nohz: Prevent bogus softirq pending warning

[Frederic Weisbecker]

On Thu, Aug 30, 2018 at 05:05:19PM +0200, Thomas Gleixner wrote:
> Commit 0a0e0829f990 ("nohz: Fix missing tick reprogram when interrupting an
> inline softirq") got backported to stable trees and now causes the NOHZ
> softirq pending warning to trigger. It's not an upstream issue as the NOHZ
> update logic has been changed there.
> 
> The problem is when a softirq disabled section gets interrupted and on
> return from interrupt the tick/nohz state is evaluated, which then can
> observe pending soft interrupts. These soft interrupts are legitimately
> pending because they cannot be processed as long as soft interrupts are
> disabled and the interrupted code will correctly process them when soft
> interrupts are reenabled.
> 
> Add a check for softirqs disabled to the pending check to prevent the
> warning.
> 
> Reported-by: Grygorii Strashko <grygorii.strashko@xxxxxx>
> Reported-by: John Crispin <john@xxxxxxxxxxx>
> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Tested-by: Grygorii Strashko <grygorii.strashko@xxxxxx>
> Tested-by: John Crispin <john@xxxxxxxxxxx>

Acked-by: Frederic Weisbecker <frederic@xxxxxxxxxx>

Thanks for cooking the patch!