From: Sudip Mukherjee <sudipm.mukherjee@xxxxxxxxx> We have dereferenced page_ext before checking it. Lets check it first and then used it. Link: http://lkml.kernel.org/r/1465249059-7883-1-git-send-email-sudipm.mukherjee@xxxxxxxxx Signed-off-by: Sudip Mukherjee <sudip.mukherjee@xxxxxxxxxxxxxxx> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> --- mm/page_owner.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/mm/page_owner.c b/mm/page_owner.c index dc92241..ec6dc18 100644 --- a/mm/page_owner.c +++ b/mm/page_owner.c @@ -295,13 +295,15 @@ void __dump_page_owner(struct page *page) .skip = 0 }; depot_stack_handle_t handle; - gfp_t gfp_mask = page_ext->gfp_mask; - int mt = gfpflags_to_migratetype(gfp_mask); + gfp_t gfp_mask; + int mt; if (unlikely(!page_ext)) { pr_alert("There is not page extension available.\n"); return; } + gfp_mask = page_ext->gfp_mask; + mt = gfpflags_to_migratetype(gfp_mask); if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags)) { pr_alert("page_owner info is not active (free page?)\n"); -- 1.9.1 -- 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>