5.4-stable review patch. If anyone has any objections, please let me know.
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From: Qiang Zhang qiang4.zhang@intel.com
[ 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@intel.com Signed-off-by: Qiang Zhang qiang4.zhang@intel.com Cc: Bill Wendling morbo@google.com Cc: Justin Stitt justinstitt@google.com Cc: Nathan Chancellor nathan@kernel.org Cc: Nick Desaulniers ndesaulniers@google.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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;