3.18-stable review patch. If anyone has any objections, please let me know.
------------------ From: Ard Biesheuvel <ard.biesheu...@linaro.org> [ Upstream commit f073bdc51771f5a5c7a8d1191bfc3ae371d44de7 ] The VM_BUG_ON() check in move_freepages() checks whether the node id of a page matches the node id of its zone. However, it does this before having checked whether the struct page pointer refers to a valid struct page to begin with. This is guaranteed in most cases, but may not be the case if CONFIG_HOLES_IN_ZONE=y. So reorder the VM_BUG_ON() with the pfn_valid_within() check. Link: http://lkml.kernel.org/r/1481706707-6211-2-git-send-email-ard.biesheu...@linaro.org Signed-off-by: Ard Biesheuvel <ard.biesheu...@linaro.org> Acked-by: Will Deacon <will.dea...@arm.com> Cc: Catalin Marinas <catalin.mari...@arm.com> Cc: Hanjun Guo <hanjun....@linaro.org> Cc: Yisheng Xie <xieyishe...@huawei.com> Cc: Robert Richter <rrich...@cavium.com> Cc: James Morse <james.mo...@arm.com> Signed-off-by: Andrew Morton <a...@linux-foundation.org> Signed-off-by: Linus Torvalds <torva...@linux-foundation.org> Signed-off-by: Sasha Levin <alexander.le...@verizon.com> Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org> --- mm/page_alloc.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1029,14 +1029,14 @@ int move_freepages(struct zone *zone, #endif for (page = start_page; page <= end_page;) { - /* Make sure we are not inadvertently changing nodes */ - VM_BUG_ON_PAGE(page_to_nid(page) != zone_to_nid(zone), page); - if (!pfn_valid_within(page_to_pfn(page))) { page++; continue; } + /* Make sure we are not inadvertently changing nodes */ + VM_BUG_ON_PAGE(page_to_nid(page) != zone_to_nid(zone), page); + if (!PageBuddy(page)) { page++; continue;
