Commit c8f61cfc authored by Miles Chen's avatar Miles Chen Committed by Linus Torvalds

mm/page_owner: clamp read count to PAGE_SIZE

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@mediatek.comSigned-off-by: default avatarMiles Chen <miles.chen@mediatek.com>
Acked-by: default avatarMichal Hocko <mhocko@suse.com>
Cc: Joe Perches <joe@perches.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 4e45f712
...@@ -351,6 +351,7 @@ print_page_owner(char __user *buf, size_t count, unsigned long pfn, ...@@ -351,6 +351,7 @@ print_page_owner(char __user *buf, size_t count, unsigned long pfn,
.skip = 0 .skip = 0
}; };
count = min_t(size_t, count, PAGE_SIZE);
kbuf = kmalloc(count, GFP_KERNEL); kbuf = kmalloc(count, GFP_KERNEL);
if (!kbuf) if (!kbuf)
return -ENOMEM; return -ENOMEM;
......
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