From: Peter Rosin <peda@xxxxxxxxxx> Subject: lib/test_string.c: avoid masking memset16/32/64 failures If a memsetXX implementation is completely broken and fails in the first iteration, when i, j, and k are all zero, the failure is masked as zero is returned. Failing in the first iteration is perhaps the most likely failure, so this makes the tests pretty much useless. Avoid the situation by always setting a random unused bit in the result on failure. Link: http://lkml.kernel.org/r/20190506124634.6807-3-peda@xxxxxxxxxx Fixes: 03270c13c5ff ("lib/string.c: add testcases for memset16/32/64") Signed-off-by: Peter Rosin <peda@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- lib/test_string.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) --- a/lib/test_string.c~lib-test_string-avoid-masking-memset16-32-64-failures +++ a/lib/test_string.c @@ -36,7 +36,7 @@ static __init int memset16_selftest(void fail: kfree(p); if (i < 256) - return (i << 24) | (j << 16) | k; + return (i << 24) | (j << 16) | k | 0x8000; return 0; } @@ -72,7 +72,7 @@ static __init int memset32_selftest(void fail: kfree(p); if (i < 256) - return (i << 24) | (j << 16) | k; + return (i << 24) | (j << 16) | k | 0x8000; return 0; } @@ -108,7 +108,7 @@ static __init int memset64_selftest(void fail: kfree(p); if (i < 256) - return (i << 24) | (j << 16) | k; + return (i << 24) | (j << 16) | k | 0x8000; return 0; } _
