From: Miles Chen <[email protected]>
The 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.
Change since v3:
- remove the change in kvmalloc
- keep kmalloc in page_owner.c
Change since v2:
- improve kvmalloc, allow sub page allocations fallback to
vmalloc when CONFIG_HIGHMEM=y
Change since v1:
- use kvmalloc()
- clamp buffer size to PAGE_SIZE
Signed-off-by: Miles Chen <[email protected]>
Cc: Joe Perches <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Michal Hocko <[email protected]>
---
mm/page_owner.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/mm/page_owner.c b/mm/page_owner.c
index 87bc0dfdb52b..b83f295e4eca 100644
--- a/mm/page_owner.c
+++ b/mm/page_owner.c
@@ -351,6 +351,7 @@ print_page_owner(char __user *buf, size_t count, unsigned
long pfn,
.skip = 0
};
+ count = count > PAGE_SIZE ? PAGE_SIZE : count;
kbuf = kmalloc(count, GFP_KERNEL);
if (!kbuf)
return -ENOMEM;
--
2.18.0
