2023-04-17 10:51:09

by Colin Ian King

Subject: [PATCH] kselftest: vDSO: Fix accumulation of uninitialized ret when CLOCK_REALTIME is undefined

In the unlikely case that CLOCK_REALTIME is not defined, variable ret is
not initialized and further accumulation of return values to ret can leave
ret in an undefined state. Fix this by initialized ret to zero and changing
the assignment of ret to an accumulation for the CLOCK_REALTIME case.

Fixes: 03f55c7952c9 ("kselftest: Extend vDSO selftest to clock_getres")
Signed-off-by: Colin Ian King <[email protected]>
---
tools/testing/selftests/vDSO/vdso_test_clock_getres.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/vDSO/vdso_test_clock_getres.c b/tools/testing/selftests/vDSO/vdso_test_clock_getres.c
index 15dcee16ff72..38d46a8bf7cb 100644
--- a/tools/testing/selftests/vDSO/vdso_test_clock_getres.c
+++ b/tools/testing/selftests/vDSO/vdso_test_clock_getres.c
@@ -84,12 +84,12 @@ static inline int vdso_test_clock(unsigned int clock_id)

int main(int argc, char **argv)
{
- int ret;
+ int ret = 0;

#if _POSIX_TIMERS > 0

#ifdef CLOCK_REALTIME
- ret = vdso_test_clock(CLOCK_REALTIME);
+ ret += vdso_test_clock(CLOCK_REALTIME);
#endif

#ifdef CLOCK_BOOTTIME
--
2.30.2

2023-04-18 10:13:25

by Vincenzo Frascino

Subject: Re: [PATCH] kselftest: vDSO: Fix accumulation of uninitialized ret when CLOCK_REALTIME is undefined

Hi Colin,

On 4/17/23 11:47, Colin Ian King wrote:
> In the unlikely case that CLOCK_REALTIME is not defined, variable ret is
> not initialized and further accumulation of return values to ret can leave
> ret in an undefined state. Fix this by initialized ret to zero and changing
> the assignment of ret to an accumulation for the CLOCK_REALTIME case.
>

I was wondering how did you find this.

Apart that:

Reviewed-by: Vincenzo Frascino <[email protected]>

> Fixes: 03f55c7952c9 ("kselftest: Extend vDSO selftest to clock_getres")
> Signed-off-by: Colin Ian King <[email protected]>
> ---
> tools/testing/selftests/vDSO/vdso_test_clock_getres.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/tools/testing/selftests/vDSO/vdso_test_clock_getres.c b/tools/testing/selftests/vDSO/vdso_test_clock_getres.c
> index 15dcee16ff72..38d46a8bf7cb 100644
> --- a/tools/testing/selftests/vDSO/vdso_test_clock_getres.c
> +++ b/tools/testing/selftests/vDSO/vdso_test_clock_getres.c
> @@ -84,12 +84,12 @@ static inline int vdso_test_clock(unsigned int clock_id)
>
> int main(int argc, char **argv)
> {
> - int ret;
> + int ret = 0;
>
> #if _POSIX_TIMERS > 0
>
> #ifdef CLOCK_REALTIME
> - ret = vdso_test_clock(CLOCK_REALTIME);
> + ret += vdso_test_clock(CLOCK_REALTIME);
> #endif
>
> #ifdef CLOCK_BOOTTIME

--
Regards,
Vincenzo

2023-04-18 10:16:57

by Colin Ian King

Subject: Re: [PATCH] kselftest: vDSO: Fix accumulation of uninitialized ret when CLOCK_REALTIME is undefined

On 18/04/2023 11:10, Vincenzo Frascino wrote:
> Hi Colin,
>
> On 4/17/23 11:47, Colin Ian King wrote:
>> In the unlikely case that CLOCK_REALTIME is not defined, variable ret is
>> not initialized and further accumulation of return values to ret can leave
>> ret in an undefined state. Fix this by initialized ret to zero and changing
>> the assignment of ret to an accumulation for the CLOCK_REALTIME case.
>>
>
> I was wondering how did you find this.

I used cppcheck --force --enable=all, this examines the #if defined() paths.

>
> Apart that:
>
> Reviewed-by: Vincenzo Frascino <[email protected]>
>
>> Fixes: 03f55c7952c9 ("kselftest: Extend vDSO selftest to clock_getres")
>> Signed-off-by: Colin Ian King <[email protected]>
>> ---
>> tools/testing/selftests/vDSO/vdso_test_clock_getres.c | 4 ++--
>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/tools/testing/selftests/vDSO/vdso_test_clock_getres.c b/tools/testing/selftests/vDSO/vdso_test_clock_getres.c
>> index 15dcee16ff72..38d46a8bf7cb 100644
>> --- a/tools/testing/selftests/vDSO/vdso_test_clock_getres.c
>> +++ b/tools/testing/selftests/vDSO/vdso_test_clock_getres.c
>> @@ -84,12 +84,12 @@ static inline int vdso_test_clock(unsigned int clock_id)
>>
>> int main(int argc, char **argv)
>> {
>> - int ret;
>> + int ret = 0;
>>
>> #if _POSIX_TIMERS > 0
>>
>> #ifdef CLOCK_REALTIME
>> - ret = vdso_test_clock(CLOCK_REALTIME);
>> + ret += vdso_test_clock(CLOCK_REALTIME);
>> #endif
>>
>> #ifdef CLOCK_BOOTTIME
>

2023-05-08 18:21:47

by Shuah Khan

Subject: Re: [PATCH] kselftest: vDSO: Fix accumulation of uninitialized ret when CLOCK_REALTIME is undefined

On 4/18/23 04:14, Colin King (gmail) wrote:
> On 18/04/2023 11:10, Vincenzo Frascino wrote:
>> Hi Colin,
>>
>> On 4/17/23 11:47, Colin Ian King wrote:
>>> In the unlikely case that CLOCK_REALTIME is not defined, variable ret is
>>> not initialized and further accumulation of return values to ret can leave
>>> ret in an undefined state. Fix this by initialized ret to zero and changing
>>> the assignment of ret to an accumulation for the CLOCK_REALTIME case.
>>>
>>
>> I was wondering how did you find this.
>
> I used cppcheck --force --enable=all, this examines the #if defined() paths.
>
>>
>> Apart that:
>>
>> Reviewed-by: Vincenzo Frascino <[email protected]>
>>

Applied to linux-kselftest next

thanks,
-- Shuah