On Fri, Nov 24, 2017 at 10:30:32AM +0100, Michal Hocko wrote: > From: Yang Shi <yang.shi@xxxxxxxxxx> > > commit f86e4271978bd93db466d6a95dad4b0fdcdb04f6 upstream. > > Per the discussion with Joonsoo Kim [1], we need check the return value > of lookup_page_ext() for all call sites since it might return NULL in > some cases, although it is unlikely, i.e. memory hotplug. > > Tested with ltp with "page_owner=0". > > [1] http://lkml.kernel.org/r/20160519002809.GA10245@js1304-P5Q-DELUXE > > [akpm@xxxxxxxxxxxxxxxxxxxx: fix build-breaking typos] > [arnd@xxxxxxxx: fix build problems from lookup_page_ext] > Link: http://lkml.kernel.org/r/6285269.2CksypHdYp@wuerfel > [akpm@xxxxxxxxxxxxxxxxxxxx: coding-style fixes] > Link: http://lkml.kernel.org/r/1464023768-31025-1-git-send-email-yang.shi@xxxxxxxxxx > Signed-off-by: Yang Shi <yang.shi@xxxxxxxxxx> > Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx> > Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> > Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> > Signed-off-by: Michal Hocko <mhocko@xxxxxxxx> Can you send a patch on top of 4.4.101 to resolve this instead? thanks, greg k-h