The patch titled
Subject: mm/mremap.c: mremap: fix unsigned compare against 0 issue
has been added to the -mm tree. Its filename is
mm-mremap-downgrade-mmap_sem-to-read-when-shrinking-fix-2.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-mremap-downgrade-mmap_sem-to-read-when-shrinking-fix-2.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-mremap-downgrade-mmap_sem-to-read-when-shrinking-fix-2.patch
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------------------------------------------------------
From: Yang Shi <yang.shi@xxxxxxxxxxxxxxxxx>
Subject: mm/mremap.c: mremap: fix unsigned compare against 0 issue
Static analysis reported an unsigned compare against 0 issue
Define an int temp variable to check the return value of __do_munmap().
Link: http://lkml.kernel.org/r/1538687672-17795-2-git-send-email-yang.shi@xxxxxxxxxxxxxxxxx
Reported-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
Signed-off-by: Yang Shi <yang.shi@xxxxxxxxxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Laurent Dufour <ldufour@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/mremap.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
--- a/mm/mremap.c~mm-mremap-downgrade-mmap_sem-to-read-when-shrinking-fix-2
+++ a/mm/mremap.c
@@ -566,12 +566,14 @@ SYSCALL_DEFINE5(mremap, unsigned long, a
* downgrades mmap_sem to read if so directed.
*/
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;
_
Patches currently in -mm which might be from yang.shi@xxxxxxxxxxxxxxxxx are
mm-mmap-zap-pages-with-read-mmap_sem-in-munmap.patch
mm-unmap-vm_hugetlb-mappings-with-optimized-path.patch
mm-unmap-vm_pfnmap-mappings-with-optimized-path.patch
mm-mremap-downgrade-mmap_sem-to-read-when-shrinking.patch
mm-mremap-downgrade-mmap_sem-to-read-when-shrinking-fix-2.patch
mm-brk-downgrade-mmap_sem-to-read-when-shrinking.patch
mm-brk-downgrade-mmap_sem-to-read-when-shrinking-fix-2.patch
mm-dax-add-comment-for-pfn_special.patch
