From 6b0b3e4e18bc92f555d01a41b57c992df6a7b152 Mon Sep 17 00:00:00 2001 From: Peter Rosin Date: Wed, 7 Aug 2019 10:21:18 +0800 Subject: [PATCH] lib/test_string.c: avoid masking memset16/32/64 failures [ 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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin Signed-off-by: Yang Yingliang --- 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 0fcdb82dca86..98a787e7a1fd 100644 --- a/lib/test_string.c +++ b/lib/test_string.c @@ -35,7 +35,7 @@ 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; } @@ -71,7 +71,7 @@ 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; } @@ -107,7 +107,7 @@ 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; } -- GitLab