linux-brain/lib/test_string.c
Peter Rosin 93b83005ea lib/test_string.c: avoid masking memset16/32/64 failures
[ Upstream commit 33d6e0ff68 ]

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: 03270c13c5 ("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>
2019-08-06 19:06:51 +02:00

142 lines
2.4 KiB
C

#include <linux/module.h>
#include <linux/printk.h>
#include <linux/slab.h>
#include <linux/string.h>
static __init int memset16_selftest(void)
{
unsigned i, j, k;
u16 v, *p;
p = kmalloc(256 * 2 * 2, GFP_KERNEL);
if (!p)
return -1;
for (i = 0; i < 256; i++) {
for (j = 0; j < 256; j++) {
memset(p, 0xa1, 256 * 2 * sizeof(v));
memset16(p + i, 0xb1b2, j);
for (k = 0; k < 512; k++) {
v = p[k];
if (k < i) {
if (v != 0xa1a1)
goto fail;
} else if (k < i + j) {
if (v != 0xb1b2)
goto fail;
} else {
if (v != 0xa1a1)
goto fail;
}
}
}
}
fail:
kfree(p);
if (i < 256)
return (i << 24) | (j << 16) | k | 0x8000;
return 0;
}
static __init int memset32_selftest(void)
{
unsigned i, j, k;
u32 v, *p;
p = kmalloc(256 * 2 * 4, GFP_KERNEL);
if (!p)
return -1;
for (i = 0; i < 256; i++) {
for (j = 0; j < 256; j++) {
memset(p, 0xa1, 256 * 2 * sizeof(v));
memset32(p + i, 0xb1b2b3b4, j);
for (k = 0; k < 512; k++) {
v = p[k];
if (k < i) {
if (v != 0xa1a1a1a1)
goto fail;
} else if (k < i + j) {
if (v != 0xb1b2b3b4)
goto fail;
} else {
if (v != 0xa1a1a1a1)
goto fail;
}
}
}
}
fail:
kfree(p);
if (i < 256)
return (i << 24) | (j << 16) | k | 0x8000;
return 0;
}
static __init int memset64_selftest(void)
{
unsigned i, j, k;
u64 v, *p;
p = kmalloc(256 * 2 * 8, GFP_KERNEL);
if (!p)
return -1;
for (i = 0; i < 256; i++) {
for (j = 0; j < 256; j++) {
memset(p, 0xa1, 256 * 2 * sizeof(v));
memset64(p + i, 0xb1b2b3b4b5b6b7b8ULL, j);
for (k = 0; k < 512; k++) {
v = p[k];
if (k < i) {
if (v != 0xa1a1a1a1a1a1a1a1ULL)
goto fail;
} else if (k < i + j) {
if (v != 0xb1b2b3b4b5b6b7b8ULL)
goto fail;
} else {
if (v != 0xa1a1a1a1a1a1a1a1ULL)
goto fail;
}
}
}
}
fail:
kfree(p);
if (i < 256)
return (i << 24) | (j << 16) | k | 0x8000;
return 0;
}
static __init int string_selftest_init(void)
{
int test, subtest;
test = 1;
subtest = memset16_selftest();
if (subtest)
goto fail;
test = 2;
subtest = memset32_selftest();
if (subtest)
goto fail;
test = 3;
subtest = memset64_selftest();
if (subtest)
goto fail;
pr_info("String selftests succeeded\n");
return 0;
fail:
pr_crit("String selftest failure %d.%08x\n", test, subtest);
return 0;
}
module_init(string_selftest_init);
MODULE_LICENSE("GPL v2");