[PATCH] mm/page_owner: avoid null pointer dereference
DORMANTno replies
From: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Date: 2016-06-06 21:37:49
Also in:
lkml
Subsystem:
memory management, memory management - page allocator, the rest · Maintainers:
Andrew Morton, Vlastimil Babka, Linus Torvalds
We have dereferenced page_ext before checking it. Lets check it first and then used it. Signed-off-by: Sudip Mukherjee <sudip.mukherjee@codethink.co.uk> --- 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 587dcca..8fa5083 100644
--- a/mm/page_owner.c
+++ b/mm/page_owner.c@@ -291,13 +291,15 @@ 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@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>