The patch titled
Subject: mm/mremap.c: fix extent calculation
has been added to the -mm tree. Its filename is
mm-mremap-fix-extent-calculation.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-mremap-fix-extent-calculation.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-mremap-fix-extent-calculation.patch
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------------------------------------------------------
From: Kalesh Singh <kaleshsingh@xxxxxxxxxx>
Subject: 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@xxxxxxxxxx
Fixes: c49dd34018026 ("mm: speedup mremap on 1GB or larger regions")
Signed-off-by: Kalesh Singh <kaleshsingh@xxxxxxxxxx>
Reported-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Tested-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Cc: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Lokesh Gidra <lokeshgidra@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/mremap.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/mm/mremap.c~mm-mremap-fix-extent-calculation
+++ a/mm/mremap.c
@@ -358,7 +358,9 @@ static unsigned long get_extent(enum pgt
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;
_
Patches currently in -mm which might be from kaleshsingh@xxxxxxxxxx are
mm-mremap-fix-extent-calculation.patch
