* free() and implicit conversion to a function pointer (was: Use of initialized variable in strtod.c)
@ 2017-03-15 22:48 Jeffrey Walton
2017-03-16 8:40 ` Corinna Vinschen
0 siblings, 1 reply; 4+ messages in thread
From: Jeffrey Walton @ 2017-03-15 22:48 UTC (permalink / raw)
To: Joel Sherrill; +Cc: newlib
> But this in __call_atexit.c is definitely correct. It is
> treating free() as a weak symbol and the only way to
> silence Coverity is to add an annotation.
>
> 136 /* Don't dynamically free the atexit array if free is not
> 137 available. */
>
> CID 175323 (#1 of 1): Function address comparison (BAD_COMPARE)
> func_conv: This implicit conversion to a function pointer is suspicious:
> free.
> Did you intend to call free?
> 138 if (!free)
> 139 break;
Well, I have not encountered that one (yet). Since Coverity is
complaining about an implicit conversion, maybe the following will
help to avoid the implicit part (and sidestep the finding):
if (free != NULL)
break;
Or perhaps:
if ((void*)free != NULL)
break;
If that works to clear the finding, then it is one of those items I
write-off as "working and playing well with the tools".
Jeff
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: free() and implicit conversion to a function pointer (was: Use of initialized variable in strtod.c)
2017-03-15 22:48 free() and implicit conversion to a function pointer (was: Use of initialized variable in strtod.c) Jeffrey Walton
@ 2017-03-16 8:40 ` Corinna Vinschen
2017-03-16 15:04 ` Joel Sherrill
0 siblings, 1 reply; 4+ messages in thread
From: Corinna Vinschen @ 2017-03-16 8:40 UTC (permalink / raw)
To: newlib
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On Mar 15 18:48, Jeffrey Walton wrote:
> > But this in __call_atexit.c is definitely correct. It is
> > treating free() as a weak symbol and the only way to
> > silence Coverity is to add an annotation.
> >
> > 136 /* Don't dynamically free the atexit array if free is not
> > 137 available. */
> >
> > CID 175323 (#1 of 1): Function address comparison (BAD_COMPARE)
> > func_conv: This implicit conversion to a function pointer is suspicious:
> > free.
> > Did you intend to call free?
> > 138 if (!free)
> > 139 break;
>
> Well, I have not encountered that one (yet). Since Coverity is
> complaining about an implicit conversion, maybe the following will
> help to avoid the implicit part (and sidestep the finding):
>
> if (free != NULL)
> break;
>
> Or perhaps:
>
> if ((void*)free != NULL)
> break;
>
> If that works to clear the finding, then it is one of those items I
> write-off as "working and playing well with the tools".
Unfortunately you have to tell covreity that "free" is a var, not a function,
but since that's not generally true... marking as false positive.
Corinna
--
Corinna Vinschen
Cygwin Maintainer
Red Hat
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: free() and implicit conversion to a function pointer (was: Use of initialized variable in strtod.c)
2017-03-16 8:40 ` Corinna Vinschen
@ 2017-03-16 15:04 ` Joel Sherrill
2017-03-16 16:23 ` Bob Dunlop
0 siblings, 1 reply; 4+ messages in thread
From: Joel Sherrill @ 2017-03-16 15:04 UTC (permalink / raw)
To: newlib
On 3/16/2017 3:39 AM, Corinna Vinschen wrote:
> On Mar 15 18:48, Jeffrey Walton wrote:
>>> But this in __call_atexit.c is definitely correct. It is
>>> treating free() as a weak symbol and the only way to
>>> silence Coverity is to add an annotation.
>>>
>>> 136 /* Don't dynamically free the atexit array if free is not
>>> 137 available. */
>>>
>>> CID 175323 (#1 of 1): Function address comparison (BAD_COMPARE)
>>> func_conv: This implicit conversion to a function pointer is suspicious:
>>> free.
>>> Did you intend to call free?
>>> 138 if (!free)
>>> 139 break;
>>
>> Well, I have not encountered that one (yet). Since Coverity is
>> complaining about an implicit conversion, maybe the following will
>> help to avoid the implicit part (and sidestep the finding):
>>
>> if (free != NULL)
>> break;
>>
>> Or perhaps:
>>
>> if ((void*)free != NULL)
>> break;
>>
>> If that works to clear the finding, then it is one of those items I
>> write-off as "working and playing well with the tools".
>
> Unfortunately you have to tell covreity that "free" is a var, not a function,
> but since that's not generally true... marking as false positive.
>
Looks like the second option resolves the issue. No Coverity specific
markup at all. It seems better to be explicit since comparing a function
name to NULL directly is rather unusual.
--joel
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: free() and implicit conversion to a function pointer (was: Use of initialized variable in strtod.c)
2017-03-16 15:04 ` Joel Sherrill
@ 2017-03-16 16:23 ` Bob Dunlop
0 siblings, 0 replies; 4+ messages in thread
From: Bob Dunlop @ 2017-03-16 16:23 UTC (permalink / raw)
To: Joel Sherrill; +Cc: newlib
On Thu, Mar 16 at 10:04, Joel Sherrill wrote:
>
> On 3/16/2017 3:39 AM, Corinna Vinschen wrote:
> > On Mar 15 18:48, Jeffrey Walton wrote:
> >>> But this in __call_atexit.c is definitely correct. It is
> >>> treating free() as a weak symbol and the only way to
> >>> silence Coverity is to add an annotation.
> >>>
> >>> 136 /* Don't dynamically free the atexit array if free is not
> >>> 137 available. */
> >>>
> >>> CID 175323 (#1 of 1): Function address comparison (BAD_COMPARE)
> >>> func_conv: This implicit conversion to a function pointer is suspicious:
> >>> free.
> >>> Did you intend to call free?
> >>> 138 if (!free)
> >>> 139 break;
> >>
> >> Well, I have not encountered that one (yet). Since Coverity is
> >> complaining about an implicit conversion, maybe the following will
> >> help to avoid the implicit part (and sidestep the finding):
> >>
> >> if (free != NULL)
> >> break;
> >>
> >> Or perhaps:
> >>
> >> if ((void*)free != NULL)
> >> break;
> >>
> >> If that works to clear the finding, then it is one of those items I
> >> write-off as "working and playing well with the tools".
> >
> > Unfortunately you have to tell covreity that "free" is a var, not a function,
> > but since that's not generally true... marking as false positive.
> >
>
> Looks like the second option resolves the issue. No Coverity specific
> markup at all. It seems better to be explicit since comparing a function
> name to NULL directly is rather unusual.
>
> --joel
Have you not just inverted the sense of the test as well.
Shouldn't it be:
if ((void*)free == NULL)
break;
--
Bob Dunlop
^ permalink raw reply [flat|nested] 4+ messages in thread
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2017-03-15 22:48 free() and implicit conversion to a function pointer (was: Use of initialized variable in strtod.c) Jeffrey Walton
2017-03-16 8:40 ` Corinna Vinschen
2017-03-16 15:04 ` Joel Sherrill
2017-03-16 16:23 ` Bob Dunlop
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