diff options
| author | Kalesh Singh <kaleshsingh@google.com> | 2020-12-29 15:14:40 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-12-29 15:36:49 -0800 |
| commit | e05986ee7a5814bec0e0075d813daca3d46e4a9e (patch) | |
| tree | 49d3a5bbfa9d636584d8e449c349cd0d75663bff /mm | |
| parent | dc2da7b45ffe954a0090f5d0310ed7b0b37d2bd2 (diff) | |
mm/mremap.c: fix extent calculation
When `next < old_addr`, `next - old_addr` arithmetic underflows causing
`extent` to be incorrect.
Make `extent` the smaller of `next - old_addr` or `old_end - old_addr`.
Link: https://lkml.kernel.org/r/20201219170433.2418867-1-kaleshsingh@google.com
Fixes: c49dd34018026 ("mm: speedup mremap on 1GB or larger regions")
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
Reported-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Lokesh Gidra <lokeshgidra@google.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/mremap.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/mm/mremap.c b/mm/mremap.c index c5590afe7165..f554320281cc 100644 --- a/mm/mremap.c +++ b/mm/mremap.c @@ -358,7 +358,9 @@ static unsigned long get_extent(enum pgt_entry entry, unsigned long old_addr, next = (old_addr + size) & mask; /* even if next overflowed, extent below will be ok */ - extent = (next > old_end) ? old_end - old_addr : next - old_addr; + extent = next - old_addr; + if (extent > old_end - old_addr) + extent = old_end - old_addr; next = (new_addr + size) & mask; if (extent > next - new_addr) extent = next - new_addr; |