From: swkhack <swkhack@xxxxxxxxx> [ 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@xxxxxxxxx Fixes: 0cf2f6f6dc60 ("mm: mlock: check against vma for actual mlock() size") Signed-off-by: swkhack <swkhack@xxxxxxxxx> Acked-by: Michal Hocko <mhocko@xxxxxxxx> Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- 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
