From: Miles Chen miles.chen@mediatek.com
[ 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@linux-foundation.org: use min_t()] Link: http://lkml.kernel.org/r/1541091607-27402-1-git-send-email-miles.chen@mediat... Signed-off-by: Miles Chen miles.chen@mediatek.com Acked-by: Michal Hocko mhocko@suse.com Cc: Joe Perches joe@perches.com Cc: Matthew Wilcox willy@infradead.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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;