From: Miles Chen <miles.chen@xxxxxxxxxxxx> [ Upstream commit c8f61cfc871fadfb73ad3eacd64fda457279e911 ] The (root-only) page owner read might allocate a large size of memory with a large read count. Allocation fails can easily occur when doing high order allocations. Clamp buffer size to PAGE_SIZE to avoid arbitrary size allocation and avoid allocation fails due to high order allocation. [akpm@xxxxxxxxxxxxxxxxxxxx: use min_t()] Link: http://lkml.kernel.org/r/1541091607-27402-1-git-send-email-miles.chen@xxxxxxxxxxxx Signed-off-by: Miles Chen <miles.chen@xxxxxxxxxxxx> Acked-by: Michal Hocko <mhocko@xxxxxxxx> Cc: Joe Perches <joe@xxxxxxxxxxx> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- mm/page_owner.c | 1 + 1 file changed, 1 insertion(+) diff --git a/mm/page_owner.c b/mm/page_owner.c index dd6b9cebf981..9c9f32fa70fa 100644 --- a/mm/page_owner.c +++ b/mm/page_owner.c @@ -107,6 +107,7 @@ print_page_owner(char __user *buf, size_t count, unsigned long pfn, .entries = &page_ext->trace_entries[0], }; + count = min_t(size_t, count, PAGE_SIZE); kbuf = kmalloc(count, GFP_KERNEL); if (!kbuf) return -ENOMEM; -- 2.19.1
