* [PATCH] KVM: selftests: Fix a condition in test_hv_cpuid()
@ 2019-05-14 10:34 Dan Carpenter
2019-05-14 13:22 ` Vitaly Kuznetsov
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Dan Carpenter @ 2019-05-14 10:34 UTC (permalink / raw)
To: Paolo Bonzini, Vitaly Kuznetsov
Cc: Radim Krčmář,
Shuah Khan, kvm, linux-kselftest, kernel-janitors
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:
--
2.20.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] KVM: selftests: Fix a condition in test_hv_cpuid()
2019-05-14 10:34 [PATCH] KVM: selftests: Fix a condition in test_hv_cpuid() Dan Carpenter
@ 2019-05-14 13:22 ` Vitaly Kuznetsov
2019-05-17 10:00 ` Thomas Huth
2019-05-20 9:58 ` Paolo Bonzini
2 siblings, 0 replies; 4+ messages in thread
From: Vitaly Kuznetsov @ 2019-05-14 13:22 UTC (permalink / raw)
To: Dan Carpenter, Paolo Bonzini
Cc: Radim Krčmář,
Shuah Khan, kvm, linux-kselftest, kernel-janitors
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] == 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,
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>
--
Vitaly
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] KVM: selftests: Fix a condition in test_hv_cpuid()
2019-05-14 10:34 [PATCH] KVM: selftests: Fix a condition in test_hv_cpuid() Dan Carpenter
2019-05-14 13:22 ` Vitaly Kuznetsov
@ 2019-05-17 10:00 ` Thomas Huth
2019-05-20 9:58 ` Paolo Bonzini
2 siblings, 0 replies; 4+ messages in thread
From: Thomas Huth @ 2019-05-17 10:00 UTC (permalink / raw)
To: Dan Carpenter, Paolo Bonzini, Vitaly Kuznetsov
Cc: Radim Krčmář,
Shuah Khan, kvm, linux-kselftest, kernel-janitors, Peter Xu
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] == 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:
>
That was yet another good example that compiling with "-Wall" is a good
idea...
Reviewed-by: Thomas Huth <thuth@redhat.com>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] KVM: selftests: Fix a condition in test_hv_cpuid()
2019-05-14 10:34 [PATCH] KVM: selftests: Fix a condition in test_hv_cpuid() Dan Carpenter
2019-05-14 13:22 ` Vitaly Kuznetsov
2019-05-17 10:00 ` Thomas Huth
@ 2019-05-20 9:58 ` Paolo Bonzini
2 siblings, 0 replies; 4+ messages in thread
From: Paolo Bonzini @ 2019-05-20 9:58 UTC (permalink / raw)
To: Dan Carpenter, Vitaly Kuznetsov
Cc: Radim Krčmář,
Shuah Khan, kvm, linux-kselftest, kernel-janitors
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] == 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:
>
Queued, thanks.
Paolo
^ permalink raw reply [flat|nested] 4+ messages in thread
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2019-05-14 10:34 [PATCH] KVM: selftests: Fix a condition in test_hv_cpuid() Dan Carpenter
2019-05-14 13:22 ` Vitaly Kuznetsov
2019-05-17 10:00 ` Thomas Huth
2019-05-20 9:58 ` Paolo Bonzini
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