This is a note to let you know that I've just added the patch titled
memtest: use {READ,WRITE}_ONCE in memory scanning
to the 6.8-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
memtest-use-read-write-_once-in-memory-scanning.patch
and it can be found in the queue-6.8 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 6ea4f1c13836f429de652f74d4fdc83efa7d4ea0
Author: Qiang Zhang <qiang4.zhang@xxxxxxxxx>
Date: Tue Mar 12 16:04:23 2024 +0800
memtest: use {READ,WRITE}_ONCE in memory scanning
[ Upstream commit 82634d7e24271698e50a3ec811e5f50de790a65f ]
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>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/mm/memtest.c b/mm/memtest.c
index 32f3e9dda8370..c2c609c391199 100644
--- a/mm/memtest.c
+++ b/mm/memtest.c
@@ -51,10 +51,10 @@ static void __init memtest(u64 pattern, phys_addr_t start_phys, phys_addr_t size
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;
