From: Peter Rosin peda@axentia.se
[ Upstream commit 33d6e0ff68af74be0c846c8e042e84a9a1a0561e ]
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@axentia.se Fixes: 03270c13c5ff ("lib/string.c: add testcases for memset16/32/64") Signed-off-by: Peter Rosin peda@axentia.se Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- lib/test_string.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/lib/test_string.c b/lib/test_string.c index bf8def01ed20..b5117ae59693 100644 --- a/lib/test_string.c +++ b/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; }