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Subject[PATCH 2/2 -mm] mm: mremap: fix unsigned compare against 0 issue
Date
Static analysis reported unsigned compare against 0 issue according to
Colin Ian King.

Defined an int temp variable to check the return value of __do_munmap().

Reported-by: Colin Ian King <colin.king@canonical.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
---
Andrew, this should be able to be folded into the original patch.

mm/mremap.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/mm/mremap.c b/mm/mremap.c
index 3524d16..f9d5d1f 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -566,12 +566,14 @@ static int vma_expandable(struct vm_area_struct *vma, unsigned long delta)
* downgrade mmap_sem to read.
*/
if (old_len >= new_len) {
- ret = __do_munmap(mm, addr+new_len, old_len - new_len,
+ int retval;
+ retval = __do_munmap(mm, addr+new_len, old_len - new_len,
&uf_unmap, true);
- if (ret < 0 && old_len != new_len)
+ if (retval < 0 && old_len != new_len) {
+ ret = retval;
goto out;
/* Returning 1 indicates mmap_sem is downgraded to read. */
- else if (ret == 1)
+ } else if (retval == 1)
downgraded = true;
ret = addr;
goto out;
--
1.8.3.1
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