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Subject[PATCH v2 2/2] mm: usercopy: Warn vmalloc/module address in check_heap_object()
Date
virt_addr_valid() could be insufficient to validate the virt addr
on some architecture, which could lead to potential BUG which has
been found on arm64/powerpc64.

Let's add WARN_ON to check if the virt addr is passed virt_addr_valid()
but is a vmalloc/module address.

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
mm/usercopy.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/mm/usercopy.c b/mm/usercopy.c
index b3de3c4eefba..ce83e0b137dd 100644
--- a/mm/usercopy.c
+++ b/mm/usercopy.c
@@ -228,6 +228,8 @@ static inline void check_heap_object(const void *ptr, unsigned long n,
if (!virt_addr_valid(ptr))
return;

+ WARN_ON_ONCE(is_vmalloc_or_module_addr(ptr));
+
/*
* When CONFIG_HIGHMEM=y, kmap_to_page() will give either the
* highmem page or fallback to virt_to_page(). The following
--
2.26.2
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