The code is trying to check that all the padding is zeroed out and it does this:
entry->padding[0] == entry->padding[1] == entry->padding[2] == 0
Assume everything is zeroed correctly, then the first comparison is true, the next comparison is false and false is equal to zero so the overall condition is true. This bug doesn't affect run time very badly, but the code should instead just check that all three paddings are zero individually.
Also the error message was copy and pasted from an earlier error and it wasn't correct.
Fixes: 7edcb7343327 ("KVM: selftests: Add hyperv_cpuid test") Signed-off-by: Dan Carpenter dan.carpenter@oracle.com --- tools/testing/selftests/kvm/x86_64/hyperv_cpuid.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/tools/testing/selftests/kvm/x86_64/hyperv_cpuid.c b/tools/testing/selftests/kvm/x86_64/hyperv_cpuid.c index 9a21e912097c..63b9fc3fdfbe 100644 --- a/tools/testing/selftests/kvm/x86_64/hyperv_cpuid.c +++ b/tools/testing/selftests/kvm/x86_64/hyperv_cpuid.c @@ -58,9 +58,8 @@ static void test_hv_cpuid(struct kvm_cpuid2 *hv_cpuid_entries, TEST_ASSERT(entry->flags == 0, ".flags field should be zero");
- TEST_ASSERT(entry->padding[0] == entry->padding[1] - == entry->padding[2] == 0, - ".index field should be zero"); + TEST_ASSERT(!entry->padding[0] && !entry->padding[1] && + !entry->padding[2], "padding should be zero");
/* * If needed for debug:
Dan Carpenter dan.carpenter@oracle.com writes:
The code is trying to check that all the padding is zeroed out and it does this:
entry->padding[0] == entry->padding[1] == entry->padding[2] == 0Assume everything is zeroed correctly, then the first comparison is true, the next comparison is false and false is equal to zero so the overall condition is true. This bug doesn't affect run time very badly, but the code should instead just check that all three paddings are zero individually.
Also the error message was copy and pasted from an earlier error and it wasn't correct.
Fixes: 7edcb7343327 ("KVM: selftests: Add hyperv_cpuid test") Signed-off-by: Dan Carpenter dan.carpenter@oracle.com
tools/testing/selftests/kvm/x86_64/hyperv_cpuid.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/tools/testing/selftests/kvm/x86_64/hyperv_cpuid.c b/tools/testing/selftests/kvm/x86_64/hyperv_cpuid.c index 9a21e912097c..63b9fc3fdfbe 100644 --- a/tools/testing/selftests/kvm/x86_64/hyperv_cpuid.c +++ b/tools/testing/selftests/kvm/x86_64/hyperv_cpuid.c @@ -58,9 +58,8 @@ static void test_hv_cpuid(struct kvm_cpuid2 *hv_cpuid_entries,
we also seem to check for 'entry->index == 0' twice here.
TEST_ASSERT(entry->flags == 0, ".flags field should be zero");
TEST_ASSERT(entry->padding[0] == entry->padding[1]== entry->padding[2] == 0,".index field should be zero");
TEST_ASSERT(!entry->padding[0] && !entry->padding[1] &&!entry->padding[2], "padding should be zero");/* * If needed for debug:
Reviewed-by: Vitaly Kuznetsov vkuznets@redhat.com
On 14/05/2019 12.34, Dan Carpenter wrote:
The code is trying to check that all the padding is zeroed out and it does this:
entry->padding[0] == entry->padding[1] == entry->padding[2] == 0Assume everything is zeroed correctly, then the first comparison is true, the next comparison is false and false is equal to zero so the overall condition is true. This bug doesn't affect run time very badly, but the code should instead just check that all three paddings are zero individually.
Also the error message was copy and pasted from an earlier error and it wasn't correct.
Fixes: 7edcb7343327 ("KVM: selftests: Add hyperv_cpuid test") Signed-off-by: Dan Carpenter dan.carpenter@oracle.com
tools/testing/selftests/kvm/x86_64/hyperv_cpuid.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/tools/testing/selftests/kvm/x86_64/hyperv_cpuid.c b/tools/testing/selftests/kvm/x86_64/hyperv_cpuid.c index 9a21e912097c..63b9fc3fdfbe 100644 --- a/tools/testing/selftests/kvm/x86_64/hyperv_cpuid.c +++ b/tools/testing/selftests/kvm/x86_64/hyperv_cpuid.c @@ -58,9 +58,8 @@ static void test_hv_cpuid(struct kvm_cpuid2 *hv_cpuid_entries, TEST_ASSERT(entry->flags == 0, ".flags field should be zero");
TEST_ASSERT(entry->padding[0] == entry->padding[1]== entry->padding[2] == 0,".index field should be zero");
TEST_ASSERT(!entry->padding[0] && !entry->padding[1] &&!entry->padding[2], "padding should be zero");/* * If needed for debug:
That was yet another good example that compiling with "-Wall" is a good idea...
Reviewed-by: Thomas Huth thuth@redhat.com
On 14/05/19 12:34, Dan Carpenter wrote:
The code is trying to check that all the padding is zeroed out and it does this:
entry->padding[0] == entry->padding[1] == entry->padding[2] == 0Assume everything is zeroed correctly, then the first comparison is true, the next comparison is false and false is equal to zero so the overall condition is true. This bug doesn't affect run time very badly, but the code should instead just check that all three paddings are zero individually.
Also the error message was copy and pasted from an earlier error and it wasn't correct.
Fixes: 7edcb7343327 ("KVM: selftests: Add hyperv_cpuid test") Signed-off-by: Dan Carpenter dan.carpenter@oracle.com
tools/testing/selftests/kvm/x86_64/hyperv_cpuid.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/tools/testing/selftests/kvm/x86_64/hyperv_cpuid.c b/tools/testing/selftests/kvm/x86_64/hyperv_cpuid.c index 9a21e912097c..63b9fc3fdfbe 100644 --- a/tools/testing/selftests/kvm/x86_64/hyperv_cpuid.c +++ b/tools/testing/selftests/kvm/x86_64/hyperv_cpuid.c @@ -58,9 +58,8 @@ static void test_hv_cpuid(struct kvm_cpuid2 *hv_cpuid_entries, TEST_ASSERT(entry->flags == 0, ".flags field should be zero");
TEST_ASSERT(entry->padding[0] == entry->padding[1]== entry->padding[2] == 0,".index field should be zero");
TEST_ASSERT(!entry->padding[0] && !entry->padding[1] &&!entry->padding[2], "padding should be zero");/* * If needed for debug:
Queued, thanks.
Paolo
linux-kselftest-mirror@lists.linaro.org
-
Dan Carpenter -
Paolo Bonzini -
Thomas Huth -
Vitaly Kuznetsov