Re: [PATCH] mm: Add WARN_ON for possibility of infinite loop if empty lists in free_pcppages_bulk'

[Pankaj Gupta]

> 
> On Fri, Aug 19, 2016 at 05:45:18PM +0530, Pankaj Gupta wrote:
> > While debugging issue in realtime kernel i found a scenario
> > which resulted in infinite loop resulting because of empty pcp->lists
> > and valid 'to_free' value. This patch is to add 'WARN_ON' in function
> > 'free_pcppages_bulk' if there is possibility of infinite loop because
> > of any bug in code.
> > 
> 
> What was the bug that allowed this situation to occur? It would imply
> the pcp count was somehow out of sync.

Yes pcp count was out of sync. It was a bug in the downstream code.
> 
> --
> Mel Gorman
> SUSE Labs
>