[ 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 46af369c13e5..1f9ee86672e8 100644 --- a/mm/mlock.c +++ b/mm/mlock.c @@ -629,11 +629,11 @@ 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;