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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, swkhack <swkhack@gmail.com>,
        Michal Hocko <mhocko@suse.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.19 36/90] mm/mlock.c: change count_mm_mlocked_page_nr return type
Date:   Mon,  8 Jul 2019 17:13:03 +0200
Message-Id: <20190708150524.419868485@linuxfoundation.org>
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[ Upstream commit 0874bb49bb21bf24deda853e8bf61b8325e24bcb ]

On a 64-bit machine the value of "vma->vm_end - vma->vm_start" may be
negative when using 32 bit ints and the "count >> PAGE_SHIFT"'s result
will be wrong.  So change the local variable and return value to
unsigned long to fix the problem.

Link: http://lkml.kernel.org/r/20190513023701.83056-1-swkhack@gmail.com
Fixes: 0cf2f6f6dc60 ("mm: mlock: check against vma for actual mlock() size")
Signed-off-by: swkhack <swkhack@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.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/mlock.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/mlock.c b/mm/mlock.c
index 41cc47e28ad6..0ab8250af1f8 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -636,11 +636,11 @@ static int apply_vma_lock_flags(unsigned long start, size_t len,
  * is also counted.
  * Return value: previously mlocked page counts
  */
-static int count_mm_mlocked_page_nr(struct mm_struct *mm,
+static unsigned long count_mm_mlocked_page_nr(struct mm_struct *mm,
 		unsigned long start, size_t len)
 {
 	struct vm_area_struct *vma;
-	int count = 0;
+	unsigned long count = 0;
 
 	if (mm == NULL)
 		mm = current->mm;
-- 
2.20.1