The patch titled
Subject: memtest: use {READ,WRITE}_ONCE in memory scanning
has been added to the -mm mm-unstable branch. Its filename is
memtest-use-readwrite_once-in-memory-scanning.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/memtest-use-readwrite_once-in-memory-scanning.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Qiang Zhang <qiang4.zhang@xxxxxxxxx>
Subject: memtest: use {READ,WRITE}_ONCE in memory scanning
Date: Tue, 12 Mar 2024 16:04:23 +0800
memtest failed to find bad memory when compiled with clang. So use
{WRITE,READ}_ONCE to access memory to avoid compiler over optimization.
Link: https://lkml.kernel.org/r/20240312080422.691222-1-qiang4.zhang@xxxxxxxxx
Signed-off-by: Qiang Zhang <qiang4.zhang@xxxxxxxxx>
Cc: Bill Wendling <morbo@xxxxxxxxxx>
Cc: Justin Stitt <justinstitt@xxxxxxxxxx>
Cc: Nathan Chancellor <nathan@xxxxxxxxxx>
Cc: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memtest.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/mm/memtest.c~memtest-use-readwrite_once-in-memory-scanning
+++ a/mm/memtest.c
@@ -51,10 +51,10 @@ static void __init memtest(u64 pattern,
last_bad = 0;
for (p = start; p < end; p++)
- *p = pattern;
+ WRITE_ONCE(*p, pattern);
for (p = start; p < end; p++, start_phys_aligned += incr) {
- if (*p == pattern)
+ if (READ_ONCE(*p) == pattern)
continue;
if (start_phys_aligned == last_bad + incr) {
last_bad += incr;
_
Patches currently in -mm which might be from qiang4.zhang@xxxxxxxxx are
memtest-use-readwrite_once-in-memory-scanning.patch
