[Qemu-devel] [PATCH] Fix: fp-test uninitialized member floatX::exp

Andrey Shinkevich posted 1 patch 4 years, 8 months ago
Failed in applying to current master (apply log)
source/slowfloat.c | 4 ++++
1 file changed, 4 insertions(+)
[Qemu-devel] [PATCH] Fix: fp-test uninitialized member floatX::exp
Posted by Andrey Shinkevich 4 years, 8 months ago
Not all the paths in the functions, such as f16ToFloatX(), initialize
the member 'exp' of the structure floatX.

Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
---
 source/slowfloat.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/tests/fp/berkeley-testfloat-3/source/slowfloat.c b/tests/fp/berkeley-testfloat-3/source/slowfloat.c
index 4e84656..6e0f0a6 100644
--- a/tests/fp/berkeley-testfloat-3/source/slowfloat.c
+++ b/tests/fp/berkeley-testfloat-3/source/slowfloat.c
@@ -623,6 +623,7 @@ static void f16ToFloatX( float16_t a, struct floatX *xPtr )
     xPtr->isInf = false;
     xPtr->isZero = false;
     xPtr->sign = ((uiA & 0x8000) != 0);
+    xPtr->exp = 0;
     exp = uiA>>10 & 0x1F;
     sig64 = uiA & 0x03FF;
     sig64 <<= 45;
@@ -759,6 +760,7 @@ static void f32ToFloatX( float32_t a, struct floatX *xPtr )
     xPtr->isInf = false;
     xPtr->isZero = false;
     xPtr->sign = ((uiA & 0x80000000) != 0);
+    xPtr->exp = 0;
     exp = uiA>>23 & 0xFF;
     sig64 = uiA & 0x007FFFFF;
     sig64 <<= 32;
@@ -895,6 +897,7 @@ static void f64ToFloatX( float64_t a, struct floatX *xPtr )
     xPtr->isInf = false;
     xPtr->isZero = false;
     xPtr->sign = ((uiA & UINT64_C( 0x8000000000000000 )) != 0);
+    xPtr->exp = 0;
     exp = uiA>>52 & 0x7FF;
     sig64 = uiA & UINT64_C( 0x000FFFFFFFFFFFFF );
     if ( exp == 0x7FF ) {
@@ -1220,6 +1223,7 @@ static void f128MToFloatX( const float128_t *aPtr, struct floatX *xPtr )
     xPtr->isZero = false;
     uiA64 = uiAPtr->v64;
     xPtr->sign = ((uiA64 & UINT64_C( 0x8000000000000000 )) != 0);
+    xPtr->exp = 0;
     exp = uiA64>>48 & 0x7FFF;
     sig.v64 = uiA64 & UINT64_C( 0x0000FFFFFFFFFFFF );
     sig.v0  = uiAPtr->v0;
-- 
1.8.3.1


Re: [Qemu-devel] [PATCH] Fix: fp-test uninitialized member floatX::exp
Posted by Andrey Shinkevich 4 years, 7 months ago
PINGING...

On 30/07/2019 13:13, Andrey Shinkevich wrote:
> Not all the paths in the functions, such as f16ToFloatX(), initialize
> the member 'exp' of the structure floatX.
> 
> Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
> ---
>   source/slowfloat.c | 4 ++++
>   1 file changed, 4 insertions(+)
> 
> diff --git a/tests/fp/berkeley-testfloat-3/source/slowfloat.c b/tests/fp/berkeley-testfloat-3/source/slowfloat.c
> index 4e84656..6e0f0a6 100644
> --- a/tests/fp/berkeley-testfloat-3/source/slowfloat.c
> +++ b/tests/fp/berkeley-testfloat-3/source/slowfloat.c
> @@ -623,6 +623,7 @@ static void f16ToFloatX( float16_t a, struct floatX *xPtr )
>       xPtr->isInf = false;
>       xPtr->isZero = false;
>       xPtr->sign = ((uiA & 0x8000) != 0);
> +    xPtr->exp = 0;
>       exp = uiA>>10 & 0x1F;
>       sig64 = uiA & 0x03FF;
>       sig64 <<= 45;
> @@ -759,6 +760,7 @@ static void f32ToFloatX( float32_t a, struct floatX *xPtr )
>       xPtr->isInf = false;
>       xPtr->isZero = false;
>       xPtr->sign = ((uiA & 0x80000000) != 0);
> +    xPtr->exp = 0;
>       exp = uiA>>23 & 0xFF;
>       sig64 = uiA & 0x007FFFFF;
>       sig64 <<= 32;
> @@ -895,6 +897,7 @@ static void f64ToFloatX( float64_t a, struct floatX *xPtr )
>       xPtr->isInf = false;
>       xPtr->isZero = false;
>       xPtr->sign = ((uiA & UINT64_C( 0x8000000000000000 )) != 0);
> +    xPtr->exp = 0;
>       exp = uiA>>52 & 0x7FF;
>       sig64 = uiA & UINT64_C( 0x000FFFFFFFFFFFFF );
>       if ( exp == 0x7FF ) {
> @@ -1220,6 +1223,7 @@ static void f128MToFloatX( const float128_t *aPtr, struct floatX *xPtr )
>       xPtr->isZero = false;
>       uiA64 = uiAPtr->v64;
>       xPtr->sign = ((uiA64 & UINT64_C( 0x8000000000000000 )) != 0);
> +    xPtr->exp = 0;
>       exp = uiA64>>48 & 0x7FFF;
>       sig.v64 = uiA64 & UINT64_C( 0x0000FFFFFFFFFFFF );
>       sig.v0  = uiAPtr->v0;
> 

-- 
With the best regards,
Andrey Shinkevich
Re: [Qemu-devel] [PATCH] Fix: fp-test uninitialized member floatX::exp
Posted by Alex Bennée 4 years, 7 months ago
Andrey Shinkevich <andrey.shinkevich@virtuozzo.com> writes:

> PINGING...

Sorry about the delay. I did attempt see if the existing code threw up
any errors when built with clang's undefined sanitizer. I think this is
because xPtr->exp will only get read if none of the xPtr->isFOO returns
false. In all those cases xPtr->exp is set.

What pointed you towards this missing initialisations?

>
> On 30/07/2019 13:13, Andrey Shinkevich wrote:
>> Not all the paths in the functions, such as f16ToFloatX(), initialize
>> the member 'exp' of the structure floatX.
>>
>> Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
>> ---
>>   source/slowfloat.c | 4 ++++
>>   1 file changed, 4 insertions(+)
>>
>> diff --git a/tests/fp/berkeley-testfloat-3/source/slowfloat.c b/tests/fp/berkeley-testfloat-3/source/slowfloat.c
>> index 4e84656..6e0f0a6 100644
>> --- a/tests/fp/berkeley-testfloat-3/source/slowfloat.c
>> +++ b/tests/fp/berkeley-testfloat-3/source/slowfloat.c
>> @@ -623,6 +623,7 @@ static void f16ToFloatX( float16_t a, struct floatX *xPtr )
>>       xPtr->isInf = false;
>>       xPtr->isZero = false;
>>       xPtr->sign = ((uiA & 0x8000) != 0);
>> +    xPtr->exp = 0;
>>       exp = uiA>>10 & 0x1F;
>>       sig64 = uiA & 0x03FF;
>>       sig64 <<= 45;
>> @@ -759,6 +760,7 @@ static void f32ToFloatX( float32_t a, struct floatX *xPtr )
>>       xPtr->isInf = false;
>>       xPtr->isZero = false;
>>       xPtr->sign = ((uiA & 0x80000000) != 0);
>> +    xPtr->exp = 0;
>>       exp = uiA>>23 & 0xFF;
>>       sig64 = uiA & 0x007FFFFF;
>>       sig64 <<= 32;
>> @@ -895,6 +897,7 @@ static void f64ToFloatX( float64_t a, struct floatX *xPtr )
>>       xPtr->isInf = false;
>>       xPtr->isZero = false;
>>       xPtr->sign = ((uiA & UINT64_C( 0x8000000000000000 )) != 0);
>> +    xPtr->exp = 0;
>>       exp = uiA>>52 & 0x7FF;
>>       sig64 = uiA & UINT64_C( 0x000FFFFFFFFFFFFF );
>>       if ( exp == 0x7FF ) {
>> @@ -1220,6 +1223,7 @@ static void f128MToFloatX( const float128_t *aPtr, struct floatX *xPtr )
>>       xPtr->isZero = false;
>>       uiA64 = uiAPtr->v64;
>>       xPtr->sign = ((uiA64 & UINT64_C( 0x8000000000000000 )) != 0);
>> +    xPtr->exp = 0;
>>       exp = uiA64>>48 & 0x7FFF;
>>       sig.v64 = uiA64 & UINT64_C( 0x0000FFFFFFFFFFFF );
>>       sig.v0  = uiAPtr->v0;
>>


--
Alex Bennée

Re: [Qemu-devel] [PATCH] Fix: fp-test uninitialized member floatX::exp
Posted by Andrey Shinkevich 4 years, 7 months ago
On 13/08/2019 15:21, Alex Bennée wrote:
> 
> Andrey Shinkevich <andrey.shinkevich@virtuozzo.com> writes:
> 
>> PINGING...
> 
> Sorry about the delay. I did attempt see if the existing code threw up
> any errors when built with clang's undefined sanitizer. I think this is
> because xPtr->exp will only get read if none of the xPtr->isFOO returns
> false. In all those cases xPtr->exp is set.
> 
> What pointed you towards this missing initialisations?
> 

I am sorry about missing the message. It appeared in other email thread 
where I didn't expect. So, I missed the response.
When I ran the fp-tests under the Valgrind, I got lots of reports about 
using uninitialized memory. They all disappeared after applying this 
patch. I concluded that there are paths that use xPtr->exp uninitialized.

$ /usr/bin/valgrind --leak-check=no --trace-children=yes 
--keep-stacktraces=alloc-and-free --track-origins=yes 
--log-file=myqemu-%p.log make check-softfloat

==720268== Conditional jump or move depends on uninitialised value(s)
==720268==    at 0x112C72: floatXRoundToInt (slowfloat.c:1371)
==720268==    by 0x115920: slow_f16_roundToInt (slowfloat.c:2408)
==720268==    by 0x133A87: test_az_f16_rx (test_az_f16_rx.c:73)
==720268==    by 0x10E635: do_testfloat (fp-test.c:304)
==720268==    by 0x10FD02: run_test (fp-test.c:1003)
==720268==    by 0x10FDA4: main (fp-test.c:1017)
==720268==  Uninitialised value was created by a stack allocation
==720268==    at 0x1158D3: slow_f16_roundToInt (slowfloat.c:2404)

==720311== Conditional jump or move depends on uninitialised value(s)
==720311==    at 0x112E54: floatXAdd (slowfloat.c:1411)
==720311==    by 0x115A2D: slow_f16_sub (slowfloat.c:2431)
==720311==    by 0x133CEC: test_abz_f16 (test_abz_f16.c:70)
==720311==    by 0x10E6D5: do_testfloat (fp-test.c:326)
==720311==    by 0x10FD02: run_test (fp-test.c:1003)
==720311==    by 0x10FDA4: main (fp-test.c:1017)
==720311==  Uninitialised value was created by a stack allocation
==720311==    at 0x1159C0: slow_f16_sub (slowfloat.c:2425)

==720273== Conditional jump or move depends on uninitialised value(s)
==720273==    at 0x113D54: floatXEq (slowfloat.c:1661)
==720273==    by 0x115EAD: slow_f16_eq_signaling (slowfloat.c:2538)
==720273==    by 0x1341D3: test_ab_f16_z_bool (test_ab_f16_z_bool.c:71)
==720273==    by 0x10E7DE: do_testfloat (fp-test.c:358)
==720273==    by 0x10FD02: run_test (fp-test.c:1003)
==720273==    by 0x10FDA4: main (fp-test.c:1017)
==720273==  Uninitialised value was created by a stack allocation
==720273==    at 0x115E38: slow_f16_eq_signaling (slowfloat.c:2530)

Even if Valgrind is wrong, the purpose of the patch is to reduce the 
number of error reports from the Valgrind to locate other memory serious 
issues, if any.

Andrey

>>
>> On 30/07/2019 13:13, Andrey Shinkevich wrote:
>>> Not all the paths in the functions, such as f16ToFloatX(), initialize
>>> the member 'exp' of the structure floatX.
>>>
>>> Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
>>> ---
>>>    source/slowfloat.c | 4 ++++
>>>    1 file changed, 4 insertions(+)
>>>
>>> diff --git a/tests/fp/berkeley-testfloat-3/source/slowfloat.c b/tests/fp/berkeley-testfloat-3/source/slowfloat.c
>>> index 4e84656..6e0f0a6 100644
>>> --- a/tests/fp/berkeley-testfloat-3/source/slowfloat.c
>>> +++ b/tests/fp/berkeley-testfloat-3/source/slowfloat.c
>>> @@ -623,6 +623,7 @@ static void f16ToFloatX( float16_t a, struct floatX *xPtr )
>>>        xPtr->isInf = false;
>>>        xPtr->isZero = false;
>>>        xPtr->sign = ((uiA & 0x8000) != 0);
>>> +    xPtr->exp = 0;
>>>        exp = uiA>>10 & 0x1F;
>>>        sig64 = uiA & 0x03FF;
>>>        sig64 <<= 45;
>>> @@ -759,6 +760,7 @@ static void f32ToFloatX( float32_t a, struct floatX *xPtr )
>>>        xPtr->isInf = false;
>>>        xPtr->isZero = false;
>>>        xPtr->sign = ((uiA & 0x80000000) != 0);
>>> +    xPtr->exp = 0;
>>>        exp = uiA>>23 & 0xFF;
>>>        sig64 = uiA & 0x007FFFFF;
>>>        sig64 <<= 32;
>>> @@ -895,6 +897,7 @@ static void f64ToFloatX( float64_t a, struct floatX *xPtr )
>>>        xPtr->isInf = false;
>>>        xPtr->isZero = false;
>>>        xPtr->sign = ((uiA & UINT64_C( 0x8000000000000000 )) != 0);
>>> +    xPtr->exp = 0;
>>>        exp = uiA>>52 & 0x7FF;
>>>        sig64 = uiA & UINT64_C( 0x000FFFFFFFFFFFFF );
>>>        if ( exp == 0x7FF ) {
>>> @@ -1220,6 +1223,7 @@ static void f128MToFloatX( const float128_t *aPtr, struct floatX *xPtr )
>>>        xPtr->isZero = false;
>>>        uiA64 = uiAPtr->v64;
>>>        xPtr->sign = ((uiA64 & UINT64_C( 0x8000000000000000 )) != 0);
>>> +    xPtr->exp = 0;
>>>        exp = uiA64>>48 & 0x7FFF;
>>>        sig.v64 = uiA64 & UINT64_C( 0x0000FFFFFFFFFFFF );
>>>        sig.v0  = uiAPtr->v0;
>>>
> 
> 
> --
> Alex Bennée
> 

-- 
With the best regards,
Andrey Shinkevich

Re: [Qemu-devel] [PATCH] Fix: fp-test uninitialized member floatX::exp
Posted by Andrey Shinkevich 4 years, 7 months ago
I just worry about this simple patch to be lost because I got some mess 
with it in my Thunderbird email threads.

Andrey

On 20/08/2019 20:01, Andrey Shinkevich wrote:
> On 13/08/2019 15:21, Alex Bennée wrote:
>>
>> Andrey Shinkevich <andrey.shinkevich@virtuozzo.com> writes:
>>
>>> PINGING...
>>
>> Sorry about the delay. I did attempt see if the existing code threw up
>> any errors when built with clang's undefined sanitizer. I think this is
>> because xPtr->exp will only get read if none of the xPtr->isFOO returns
>> false. In all those cases xPtr->exp is set.
>>
>> What pointed you towards this missing initialisations?
>>
> 
> I am sorry about missing the message. It appeared in other email thread
> where I didn't expect. So, I missed the response.
> When I ran the fp-tests under the Valgrind, I got lots of reports about
> using uninitialized memory. They all disappeared after applying this
> patch. I concluded that there are paths that use xPtr->exp uninitialized.
> 
> $ /usr/bin/valgrind --leak-check=no --trace-children=yes
> --keep-stacktraces=alloc-and-free --track-origins=yes
> --log-file=myqemu-%p.log make check-softfloat
> 
> ==720268== Conditional jump or move depends on uninitialised value(s)
> ==720268==    at 0x112C72: floatXRoundToInt (slowfloat.c:1371)
> ==720268==    by 0x115920: slow_f16_roundToInt (slowfloat.c:2408)
> ==720268==    by 0x133A87: test_az_f16_rx (test_az_f16_rx.c:73)
> ==720268==    by 0x10E635: do_testfloat (fp-test.c:304)
> ==720268==    by 0x10FD02: run_test (fp-test.c:1003)
> ==720268==    by 0x10FDA4: main (fp-test.c:1017)
> ==720268==  Uninitialised value was created by a stack allocation
> ==720268==    at 0x1158D3: slow_f16_roundToInt (slowfloat.c:2404)
> 
> ==720311== Conditional jump or move depends on uninitialised value(s)
> ==720311==    at 0x112E54: floatXAdd (slowfloat.c:1411)
> ==720311==    by 0x115A2D: slow_f16_sub (slowfloat.c:2431)
> ==720311==    by 0x133CEC: test_abz_f16 (test_abz_f16.c:70)
> ==720311==    by 0x10E6D5: do_testfloat (fp-test.c:326)
> ==720311==    by 0x10FD02: run_test (fp-test.c:1003)
> ==720311==    by 0x10FDA4: main (fp-test.c:1017)
> ==720311==  Uninitialised value was created by a stack allocation
> ==720311==    at 0x1159C0: slow_f16_sub (slowfloat.c:2425)
> 
> ==720273== Conditional jump or move depends on uninitialised value(s)
> ==720273==    at 0x113D54: floatXEq (slowfloat.c:1661)
> ==720273==    by 0x115EAD: slow_f16_eq_signaling (slowfloat.c:2538)
> ==720273==    by 0x1341D3: test_ab_f16_z_bool (test_ab_f16_z_bool.c:71)
> ==720273==    by 0x10E7DE: do_testfloat (fp-test.c:358)
> ==720273==    by 0x10FD02: run_test (fp-test.c:1003)
> ==720273==    by 0x10FDA4: main (fp-test.c:1017)
> ==720273==  Uninitialised value was created by a stack allocation
> ==720273==    at 0x115E38: slow_f16_eq_signaling (slowfloat.c:2530)
> 
> Even if Valgrind is wrong, the purpose of the patch is to reduce the
> number of error reports from the Valgrind to locate other memory serious
> issues, if any.
> 
> Andrey
> 
>>>
>>> On 30/07/2019 13:13, Andrey Shinkevich wrote:
>>>> Not all the paths in the functions, such as f16ToFloatX(), initialize
>>>> the member 'exp' of the structure floatX.
>>>>
>>>> Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
>>>> ---
>>>>     source/slowfloat.c | 4 ++++
>>>>     1 file changed, 4 insertions(+)
>>>>
>>>> diff --git a/tests/fp/berkeley-testfloat-3/source/slowfloat.c b/tests/fp/berkeley-testfloat-3/source/slowfloat.c
>>>> index 4e84656..6e0f0a6 100644
>>>> --- a/tests/fp/berkeley-testfloat-3/source/slowfloat.c
>>>> +++ b/tests/fp/berkeley-testfloat-3/source/slowfloat.c
>>>> @@ -623,6 +623,7 @@ static void f16ToFloatX( float16_t a, struct floatX *xPtr )
>>>>         xPtr->isInf = false;
>>>>         xPtr->isZero = false;
>>>>         xPtr->sign = ((uiA & 0x8000) != 0);
>>>> +    xPtr->exp = 0;
>>>>         exp = uiA>>10 & 0x1F;
>>>>         sig64 = uiA & 0x03FF;
>>>>         sig64 <<= 45;
>>>> @@ -759,6 +760,7 @@ static void f32ToFloatX( float32_t a, struct floatX *xPtr )
>>>>         xPtr->isInf = false;
>>>>         xPtr->isZero = false;
>>>>         xPtr->sign = ((uiA & 0x80000000) != 0);
>>>> +    xPtr->exp = 0;
>>>>         exp = uiA>>23 & 0xFF;
>>>>         sig64 = uiA & 0x007FFFFF;
>>>>         sig64 <<= 32;
>>>> @@ -895,6 +897,7 @@ static void f64ToFloatX( float64_t a, struct floatX *xPtr )
>>>>         xPtr->isInf = false;
>>>>         xPtr->isZero = false;
>>>>         xPtr->sign = ((uiA & UINT64_C( 0x8000000000000000 )) != 0);
>>>> +    xPtr->exp = 0;
>>>>         exp = uiA>>52 & 0x7FF;
>>>>         sig64 = uiA & UINT64_C( 0x000FFFFFFFFFFFFF );
>>>>         if ( exp == 0x7FF ) {
>>>> @@ -1220,6 +1223,7 @@ static void f128MToFloatX( const float128_t *aPtr, struct floatX *xPtr )
>>>>         xPtr->isZero = false;
>>>>         uiA64 = uiAPtr->v64;
>>>>         xPtr->sign = ((uiA64 & UINT64_C( 0x8000000000000000 )) != 0);
>>>> +    xPtr->exp = 0;
>>>>         exp = uiA64>>48 & 0x7FFF;
>>>>         sig.v64 = uiA64 & UINT64_C( 0x0000FFFFFFFFFFFF );
>>>>         sig.v0  = uiAPtr->v0;
>>>>
>>
>>
>> --
>> Alex Bennée
>>
> 

-- 
With the best regards,
Andrey Shinkevich

Re: [Qemu-devel] [PATCH] Fix: fp-test uninitialized member floatX::exp
Posted by Alex Bennée 4 years, 7 months ago
Andrey Shinkevich <andrey.shinkevich@virtuozzo.com> writes:

> On 13/08/2019 15:21, Alex Bennée wrote:
>>
>> Andrey Shinkevich <andrey.shinkevich@virtuozzo.com> writes:
>>
>>> PINGING...
>>
>> Sorry about the delay. I did attempt see if the existing code threw up
>> any errors when built with clang's undefined sanitizer. I think this is
>> because xPtr->exp will only get read if none of the xPtr->isFOO returns
>> false. In all those cases xPtr->exp is set.
>>
>> What pointed you towards this missing initialisations?
>>
>
> I am sorry about missing the message. It appeared in other email thread
> where I didn't expect. So, I missed the response.
> When I ran the fp-tests under the Valgrind, I got lots of reports about
> using uninitialized memory. They all disappeared after applying this
> patch. I concluded that there are paths that use xPtr->exp uninitialized.
>
> $ /usr/bin/valgrind --leak-check=no --trace-children=yes
> --keep-stacktraces=alloc-and-free --track-origins=yes
> --log-file=myqemu-%p.log make check-softfloat

It would be useful to know what tests are being run (V=1 will show you).
I can't replicate the failure with:

  valgrind --leak-check=no --trace-children=yes --keep-stacktraces=alloc-and-free --track-origins=yes ./fp-test -s -l 2 -r all  f16_to_f32 f16_to_f64 f16_to_f128 f32_to_f16 f32_to_f64

>
> ==720268== Conditional jump or move depends on uninitialised value(s)
> ==720268==    at 0x112C72: floatXRoundToInt (slowfloat.c:1371)
> ==720268==    by 0x115920: slow_f16_roundToInt (slowfloat.c:2408)
> ==720268==    by 0x133A87: test_az_f16_rx (test_az_f16_rx.c:73)
> ==720268==    by 0x10E635: do_testfloat (fp-test.c:304)
> ==720268==    by 0x10FD02: run_test (fp-test.c:1003)
> ==720268==    by 0x10FDA4: main (fp-test.c:1017)
> ==720268==  Uninitialised value was created by a stack allocation
> ==720268==    at 0x1158D3: slow_f16_roundToInt (slowfloat.c:2404)
>
> ==720311== Conditional jump or move depends on uninitialised value(s)
> ==720311==    at 0x112E54: floatXAdd (slowfloat.c:1411)
> ==720311==    by 0x115A2D: slow_f16_sub (slowfloat.c:2431)
> ==720311==    by 0x133CEC: test_abz_f16 (test_abz_f16.c:70)
> ==720311==    by 0x10E6D5: do_testfloat (fp-test.c:326)
> ==720311==    by 0x10FD02: run_test (fp-test.c:1003)
> ==720311==    by 0x10FDA4: main (fp-test.c:1017)
> ==720311==  Uninitialised value was created by a stack allocation
> ==720311==    at 0x1159C0: slow_f16_sub (slowfloat.c:2425)
>
> ==720273== Conditional jump or move depends on uninitialised value(s)
> ==720273==    at 0x113D54: floatXEq (slowfloat.c:1661)
> ==720273==    by 0x115EAD: slow_f16_eq_signaling (slowfloat.c:2538)
> ==720273==    by 0x1341D3: test_ab_f16_z_bool (test_ab_f16_z_bool.c:71)
> ==720273==    by 0x10E7DE: do_testfloat (fp-test.c:358)
> ==720273==    by 0x10FD02: run_test (fp-test.c:1003)
> ==720273==    by 0x10FDA4: main (fp-test.c:1017)
> ==720273==  Uninitialised value was created by a stack allocation
> ==720273==    at 0x115E38: slow_f16_eq_signaling (slowfloat.c:2530)
>
> Even if Valgrind is wrong, the purpose of the patch is to reduce the
> number of error reports from the Valgrind to locate other memory serious
> issues, if any.
>
> Andrey
>
>>>
>>> On 30/07/2019 13:13, Andrey Shinkevich wrote:
>>>> Not all the paths in the functions, such as f16ToFloatX(), initialize
>>>> the member 'exp' of the structure floatX.
>>>>
>>>> Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
>>>> ---
>>>>    source/slowfloat.c | 4 ++++
>>>>    1 file changed, 4 insertions(+)
>>>>
>>>> diff --git a/tests/fp/berkeley-testfloat-3/source/slowfloat.c b/tests/fp/berkeley-testfloat-3/source/slowfloat.c
>>>> index 4e84656..6e0f0a6 100644
>>>> --- a/tests/fp/berkeley-testfloat-3/source/slowfloat.c
>>>> +++ b/tests/fp/berkeley-testfloat-3/source/slowfloat.c
>>>> @@ -623,6 +623,7 @@ static void f16ToFloatX( float16_t a, struct floatX *xPtr )
>>>>        xPtr->isInf = false;
>>>>        xPtr->isZero = false;
>>>>        xPtr->sign = ((uiA & 0x8000) != 0);
>>>> +    xPtr->exp = 0;
>>>>        exp = uiA>>10 & 0x1F;
>>>>        sig64 = uiA & 0x03FF;
>>>>        sig64 <<= 45;
>>>> @@ -759,6 +760,7 @@ static void f32ToFloatX( float32_t a, struct floatX *xPtr )
>>>>        xPtr->isInf = false;
>>>>        xPtr->isZero = false;
>>>>        xPtr->sign = ((uiA & 0x80000000) != 0);
>>>> +    xPtr->exp = 0;
>>>>        exp = uiA>>23 & 0xFF;
>>>>        sig64 = uiA & 0x007FFFFF;
>>>>        sig64 <<= 32;
>>>> @@ -895,6 +897,7 @@ static void f64ToFloatX( float64_t a, struct floatX *xPtr )
>>>>        xPtr->isInf = false;
>>>>        xPtr->isZero = false;
>>>>        xPtr->sign = ((uiA & UINT64_C( 0x8000000000000000 )) != 0);
>>>> +    xPtr->exp = 0;
>>>>        exp = uiA>>52 & 0x7FF;
>>>>        sig64 = uiA & UINT64_C( 0x000FFFFFFFFFFFFF );
>>>>        if ( exp == 0x7FF ) {
>>>> @@ -1220,6 +1223,7 @@ static void f128MToFloatX( const float128_t *aPtr, struct floatX *xPtr )
>>>>        xPtr->isZero = false;
>>>>        uiA64 = uiAPtr->v64;
>>>>        xPtr->sign = ((uiA64 & UINT64_C( 0x8000000000000000 )) != 0);
>>>> +    xPtr->exp = 0;
>>>>        exp = uiA64>>48 & 0x7FFF;
>>>>        sig.v64 = uiA64 & UINT64_C( 0x0000FFFFFFFFFFFF );
>>>>        sig.v0  = uiAPtr->v0;
>>>>
>>
>>
>> --
>> Alex Bennée
>>


--
Alex Bennée

Re: [Qemu-devel] [PATCH] Fix: fp-test uninitialized member floatX::exp
Posted by Andrey Shinkevich 4 years, 7 months ago

On 27/08/2019 18:59, Alex Bennée wrote:
> 
> Andrey Shinkevich <andrey.shinkevich@virtuozzo.com> writes:
> 
>> On 13/08/2019 15:21, Alex Bennée wrote:
>>>
>>> Andrey Shinkevich <andrey.shinkevich@virtuozzo.com> writes:
>>>
>>>> PINGING...
>>>
>>> Sorry about the delay. I did attempt see if the existing code threw up
>>> any errors when built with clang's undefined sanitizer. I think this is
>>> because xPtr->exp will only get read if none of the xPtr->isFOO returns
>>> false. In all those cases xPtr->exp is set.
>>>
>>> What pointed you towards this missing initialisations?
>>>
>>
>> I am sorry about missing the message. It appeared in other email thread
>> where I didn't expect. So, I missed the response.
>> When I ran the fp-tests under the Valgrind, I got lots of reports about
>> using uninitialized memory. They all disappeared after applying this
>> patch. I concluded that there are paths that use xPtr->exp uninitialized.
>>
>> $ /usr/bin/valgrind --leak-check=no --trace-children=yes
>> --keep-stacktraces=alloc-and-free --track-origins=yes
>> --log-file=myqemu-%p.log make check-softfloat
> 
> It would be useful to know what tests are being run (V=1 will show you).
> I can't replicate the failure with:
> 
>    valgrind --leak-check=no --trace-children=yes --keep-stacktraces=alloc-and-free --track-origins=yes ./fp-test -s -l 2 -r all  f16_to_f32 f16_to_f64 f16_to_f128 f32_to_f16 f32_to_f64
> 

They are

./fp-test -s -l 1 -r all f16_roundToInt f32_roundToInt f64_roundToInt 
f128_roundToInt

./fp-test -s -l 1 -r all f16_eq f32_eq f64_eq extF80_eq f128_eq

./fp-test -s -l 1 -r all f16_eq_signaling f32_eq_signaling 
f64_eq_signaling extF80_eq_signaling f128_eq_signaling

./fp-test -s -l 1 -r all f16_add f32_add f64_add extF80_add f128_add

./fp-test -s -l 1 -r all f16_sub f32_sub f64_sub extF80_sub f128_sub

Andrey

>>
>> ==720268== Conditional jump or move depends on uninitialised value(s)
>> ==720268==    at 0x112C72: floatXRoundToInt (slowfloat.c:1371)
>> ==720268==    by 0x115920: slow_f16_roundToInt (slowfloat.c:2408)
>> ==720268==    by 0x133A87: test_az_f16_rx (test_az_f16_rx.c:73)
>> ==720268==    by 0x10E635: do_testfloat (fp-test.c:304)
>> ==720268==    by 0x10FD02: run_test (fp-test.c:1003)
>> ==720268==    by 0x10FDA4: main (fp-test.c:1017)
>> ==720268==  Uninitialised value was created by a stack allocation
>> ==720268==    at 0x1158D3: slow_f16_roundToInt (slowfloat.c:2404)
>>
>> ==720311== Conditional jump or move depends on uninitialised value(s)
>> ==720311==    at 0x112E54: floatXAdd (slowfloat.c:1411)
>> ==720311==    by 0x115A2D: slow_f16_sub (slowfloat.c:2431)
>> ==720311==    by 0x133CEC: test_abz_f16 (test_abz_f16.c:70)
>> ==720311==    by 0x10E6D5: do_testfloat (fp-test.c:326)
>> ==720311==    by 0x10FD02: run_test (fp-test.c:1003)
>> ==720311==    by 0x10FDA4: main (fp-test.c:1017)
>> ==720311==  Uninitialised value was created by a stack allocation
>> ==720311==    at 0x1159C0: slow_f16_sub (slowfloat.c:2425)
>>
>> ==720273== Conditional jump or move depends on uninitialised value(s)
>> ==720273==    at 0x113D54: floatXEq (slowfloat.c:1661)
>> ==720273==    by 0x115EAD: slow_f16_eq_signaling (slowfloat.c:2538)
>> ==720273==    by 0x1341D3: test_ab_f16_z_bool (test_ab_f16_z_bool.c:71)
>> ==720273==    by 0x10E7DE: do_testfloat (fp-test.c:358)
>> ==720273==    by 0x10FD02: run_test (fp-test.c:1003)
>> ==720273==    by 0x10FDA4: main (fp-test.c:1017)
>> ==720273==  Uninitialised value was created by a stack allocation
>> ==720273==    at 0x115E38: slow_f16_eq_signaling (slowfloat.c:2530)
>>
>> Even if Valgrind is wrong, the purpose of the patch is to reduce the
>> number of error reports from the Valgrind to locate other memory serious
>> issues, if any.
>>
>> Andrey
>>
>>>>
>>>> On 30/07/2019 13:13, Andrey Shinkevich wrote:
>>>>> Not all the paths in the functions, such as f16ToFloatX(), initialize
>>>>> the member 'exp' of the structure floatX.
>>>>>
>>>>> Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
>>>>> ---
>>>>>     source/slowfloat.c | 4 ++++
>>>>>     1 file changed, 4 insertions(+)
>>>>>
>>>>> diff --git a/tests/fp/berkeley-testfloat-3/source/slowfloat.c b/tests/fp/berkeley-testfloat-3/source/slowfloat.c
>>>>> index 4e84656..6e0f0a6 100644
>>>>> --- a/tests/fp/berkeley-testfloat-3/source/slowfloat.c
>>>>> +++ b/tests/fp/berkeley-testfloat-3/source/slowfloat.c
>>>>> @@ -623,6 +623,7 @@ static void f16ToFloatX( float16_t a, struct floatX *xPtr )
>>>>>         xPtr->isInf = false;
>>>>>         xPtr->isZero = false;
>>>>>         xPtr->sign = ((uiA & 0x8000) != 0);
>>>>> +    xPtr->exp = 0;
>>>>>         exp = uiA>>10 & 0x1F;
>>>>>         sig64 = uiA & 0x03FF;
>>>>>         sig64 <<= 45;
>>>>> @@ -759,6 +760,7 @@ static void f32ToFloatX( float32_t a, struct floatX *xPtr )
>>>>>         xPtr->isInf = false;
>>>>>         xPtr->isZero = false;
>>>>>         xPtr->sign = ((uiA & 0x80000000) != 0);
>>>>> +    xPtr->exp = 0;
>>>>>         exp = uiA>>23 & 0xFF;
>>>>>         sig64 = uiA & 0x007FFFFF;
>>>>>         sig64 <<= 32;
>>>>> @@ -895,6 +897,7 @@ static void f64ToFloatX( float64_t a, struct floatX *xPtr )
>>>>>         xPtr->isInf = false;
>>>>>         xPtr->isZero = false;
>>>>>         xPtr->sign = ((uiA & UINT64_C( 0x8000000000000000 )) != 0);
>>>>> +    xPtr->exp = 0;
>>>>>         exp = uiA>>52 & 0x7FF;
>>>>>         sig64 = uiA & UINT64_C( 0x000FFFFFFFFFFFFF );
>>>>>         if ( exp == 0x7FF ) {
>>>>> @@ -1220,6 +1223,7 @@ static void f128MToFloatX( const float128_t *aPtr, struct floatX *xPtr )
>>>>>         xPtr->isZero = false;
>>>>>         uiA64 = uiAPtr->v64;
>>>>>         xPtr->sign = ((uiA64 & UINT64_C( 0x8000000000000000 )) != 0);
>>>>> +    xPtr->exp = 0;
>>>>>         exp = uiA64>>48 & 0x7FFF;
>>>>>         sig.v64 = uiA64 & UINT64_C( 0x0000FFFFFFFFFFFF );
>>>>>         sig.v0  = uiAPtr->v0;
>>>>>
>>>
>>>
>>> --
>>> Alex Bennée
>>>
> 
> 
> --
> Alex Bennée
> 

-- 
With the best regards,
Andrey Shinkevich

Re: [Qemu-devel] [PATCH] Fix: fp-test uninitialized member floatX::exp
Posted by Andrey Shinkevich 4 years, 7 months ago
PINGING...

On 30/07/2019 13:13, Andrey Shinkevich wrote:
> Not all the paths in the functions, such as f16ToFloatX(), initialize
> the member 'exp' of the structure floatX.
> 
> Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
> ---
>   source/slowfloat.c | 4 ++++
>   1 file changed, 4 insertions(+)
> 
> diff --git a/tests/fp/berkeley-testfloat-3/source/slowfloat.c b/tests/fp/berkeley-testfloat-3/source/slowfloat.c
> index 4e84656..6e0f0a6 100644
> --- a/tests/fp/berkeley-testfloat-3/source/slowfloat.c
> +++ b/tests/fp/berkeley-testfloat-3/source/slowfloat.c
> @@ -623,6 +623,7 @@ static void f16ToFloatX( float16_t a, struct floatX *xPtr )
>       xPtr->isInf = false;
>       xPtr->isZero = false;
>       xPtr->sign = ((uiA & 0x8000) != 0);
> +    xPtr->exp = 0;
>       exp = uiA>>10 & 0x1F;
>       sig64 = uiA & 0x03FF;
>       sig64 <<= 45;
> @@ -759,6 +760,7 @@ static void f32ToFloatX( float32_t a, struct floatX *xPtr )
>       xPtr->isInf = false;
>       xPtr->isZero = false;
>       xPtr->sign = ((uiA & 0x80000000) != 0);
> +    xPtr->exp = 0;
>       exp = uiA>>23 & 0xFF;
>       sig64 = uiA & 0x007FFFFF;
>       sig64 <<= 32;
> @@ -895,6 +897,7 @@ static void f64ToFloatX( float64_t a, struct floatX *xPtr )
>       xPtr->isInf = false;
>       xPtr->isZero = false;
>       xPtr->sign = ((uiA & UINT64_C( 0x8000000000000000 )) != 0);
> +    xPtr->exp = 0;
>       exp = uiA>>52 & 0x7FF;
>       sig64 = uiA & UINT64_C( 0x000FFFFFFFFFFFFF );
>       if ( exp == 0x7FF ) {
> @@ -1220,6 +1223,7 @@ static void f128MToFloatX( const float128_t *aPtr, struct floatX *xPtr )
>       xPtr->isZero = false;
>       uiA64 = uiAPtr->v64;
>       xPtr->sign = ((uiA64 & UINT64_C( 0x8000000000000000 )) != 0);
> +    xPtr->exp = 0;
>       exp = uiA64>>48 & 0x7FFF;
>       sig.v64 = uiA64 & UINT64_C( 0x0000FFFFFFFFFFFF );
>       sig.v0  = uiAPtr->v0;
> 

-- 
With the best regards,
Andrey Shinkevich
Re: [Qemu-devel] [PATCH] Fix: fp-test uninitialized member floatX::exp
Posted by Peter Maydell 4 years, 7 months ago
On Tue, 20 Aug 2019 at 16:18, Andrey Shinkevich
<andrey.shinkevich@virtuozzo.com> wrote:
>
> PINGING...

Hi -- Alex asked you a question on the 13th when you last
pinged this patch, which I don't think you've replied to
yet (or if you did then my mail client has filed it somewhere
unhelpful).

thanks
-- PMM