On Wed, Jan 04, 2023 at 07:00:55PM +0000, Yu, Fenghua wrote: > So the current patch is good without any change, right? No, you'd definitely need mmget_not_zero() (and a grab in advance of this, though from the sounds of it you may already have it), I definitely don't think the patch as-is works, see my reply to Alistair.