| From | Sasha Levin <> | Subject | [PATCH AUTOSEL 4.4 72/80] mm/page_owner: clamp read count to PAGE_SIZE | Date | Mon, 28 Jan 2019 11:23:53 -0500 |
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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@mediatek.com 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; -- 2.19.1
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