Commit 6e7044f1 authored Mar 12, 2024 by Qiang Zhang Committed by Greg Kroah-Hartman Apr 13, 2024

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@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>

parent 6206e70d

mm/memtest.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -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;