On Fri, Aug 19, 2016 at 09:07:21AM -0400, Pankaj Gupta wrote: > > > > > 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. If the bug is not in the mainline code, I think it would be inappropriate to add unnecessary code to a relatively hot path. At most, it should be a VM_BUG_ON but the soft lockup should be clear enough. -- Mel Gorman SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>