5.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Qiang Zhang <qiang4.zhang@xxxxxxxxx> [ 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> --- mm/memtest.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/mm/memtest.c b/mm/memtest.c index f53ace709ccd8..d407373f225b4 100644 --- a/mm/memtest.c +++ b/mm/memtest.c @@ -46,10 +46,10 @@ 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; -- 2.43.0