Commit 33d6e0ff authored Jul 16, 2019 by Peter Rosin Committed by Linus Torvalds Jul 16, 2019

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@axentia.se


Fixes: 03270c13 ("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>

parent b0975710

lib/test_string.c

+3 −3

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

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