linux-kernel - [PATCH] mm: usercopy: move the virt_addr_valid() below the is_vmalloc

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Date:   Thu, 5 May 2022 07:10:37 +0000
From:   Yuanzheng Song <songyuanzheng@...wei.com>
To:     <akpm@...ux-foundation.org>
CC:     <linux-mm@...ck.org>, <linux-kernel@...r.kernel.org>,
        Yuanzheng Song <songyuanzheng@...wei.com>
Subject: [PATCH] mm: usercopy: move the virt_addr_valid() below the is_vmalloc_addr()

The is_kmap_addr() and the is_vmalloc_addr() in the check_heap_object()
will not work, because the virt_addr_valid() will exclude the kmap and
vmalloc regions. So let's move the virt_addr_valid() below
the is_vmalloc_addr().

Signed-off-by: Yuanzheng Song <songyuanzheng@...wei.com>
---
 mm/usercopy.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/mm/usercopy.c b/mm/usercopy.c
index ac8a093e90c1..baeacc735b83 100644
--- a/mm/usercopy.c
+++ b/mm/usercopy.c
@@ -163,9 +163,6 @@ static inline void check_heap_object(const void *ptr, unsigned long n,
 {
 	struct folio *folio;
 
-	if (!virt_addr_valid(ptr))
-		return;
-
 	if (is_kmap_addr(ptr)) {
 		unsigned long page_end = (unsigned long)ptr | (PAGE_SIZE - 1);
 
@@ -190,6 +187,9 @@ static inline void check_heap_object(const void *ptr, unsigned long n,
 		return;
 	}
 
+	if (!virt_addr_valid(ptr))
+		return;
+
 	folio = virt_to_folio(ptr);
 
 	if (folio_test_slab(folio)) {
-- 
2.25.1