Re: [Discuss-gnuradio] Fwd: New Defects reported by Coverity Scan for GNURadio

[Philip Balister]

On 03/03/2014 05:00 PM, Tom Rondeau wrote:
> On Mon, Mar 3, 2014 at 4:58 PM, Philip Balister <address@hidden> wrote:
>> The latest Coverity scan showed these new items. We should probably
>> double check them. The Null dereference is likely related to the order
>> in which some class methods get called.
>>
>> The compare against zero of an unsigned number should be checked to make
>> sure that is what was really meant.
>>
>> Philip
> 
> Too late. I already pushed fixes for these and updated Coverity.
> 
> I noticed the defect emails and it's related to code I just pushed
> this weekend, so it was easy enough for me to get them while they were
> fresh in my mind.
> 
> Thanks for keeping on top of this, though.

Thanks. I figured some visibility would encourage more people to pay
attention to Coverity.

You can sign up for Soverity at https://scan.coverity.com/ and then
request access to the GNU Radio reports. It's a great way to learn about
some interesting coding errors.

While things like comparing unsigned ints with 0 may seem trivial, they
can be pointers to actual bugs.

Philip

> 
> Tom
> 
> 
> 
>> ** CID 1189412:  Explicit null dereferenced  (FORWARD_NULL)
>> /var/lib/jenkins/jobs/GNURadio-master/workspace/gnuradio/gr-filter/lib/fft_filter.cc:
>> 355 in gr::filter::kernel::fft_filter_ccf::fft_filter_ccf(int, const
>> std::vector<float, std::allocator<float>> &, int)()
>>
>> ** CID 1189413:  Unsigned compared against 0  (NO_EFFECT)
>> /var/lib/jenkins/jobs/GNURadio-master/workspace/gnuradio/gr-filter/lib/pfb_synthesizer_ccf_impl.cc:
>> 225 in gr::filter::pfb_synthesizer_ccf_impl::set_channel_map(const
>> std::vector<int, std::allocator<int>> &)()
>>
>>
>> ________________________________________________________________________________________________________
>> *** CID 1189412:  Explicit null dereferenced  (FORWARD_NULL)
>> /var/lib/jenkins/jobs/GNURadio-master/workspace/gnuradio/gr-filter/lib/fft_filter.cc:
>> 355 in gr::filter::kernel::fft_filter_ccf::fft_filter_ccf(int, const
>> std::vector<float, std::allocator<float>> &, int)()
>> 349
>> /**************************************************************/
>> 350
>> 351
>> 352           fft_filter_ccf::fft_filter_ccf(int decimation,
>> 353                                          const std::vector<float> &taps,
>> 354                                          int nthreads)
>>>>>     CID 1189412:  Explicit null dereferenced  (FORWARD_NULL)
>>>>>     Assigning: "this->d_fwdfft" = "NULL".
>> 355             : d_fftsize(-1), d_decimation(decimation), d_fwdfft(0),
>> 356               d_invfft(0), d_nthreads(nthreads), d_xformed_taps(NULL)
>> 357           {
>> 358             set_taps(taps);
>> 359           }
>> 360
>>
>> ________________________________________________________________________________________________________
>> *** CID 1189413:  Unsigned compared against 0  (NO_EFFECT)
>> /var/lib/jenkins/jobs/GNURadio-master/workspace/gnuradio/gr-filter/lib/pfb_synthesizer_ccf_impl.cc:
>> 225 in gr::filter::pfb_synthesizer_ccf_impl::set_channel_map(const
>> std::vector<int, std::allocator<int>> &)()
>> 219         {
>> 220           gr::thread::scoped_lock guard(d_mutex);
>> 221
>> 222           if(map.size() > 0) {
>> 223             unsigned int max = (unsigned
>> int)*std::max_element(map.begin(), map.end());
>> 224             unsigned int min = (unsigned
>> int)*std::min_element(map.begin(), map.end());
>>>>>     CID 1189413:  Unsigned compared against 0  (NO_EFFECT)
>>>>>     This less-than-zero comparison of an unsigned value is never true. 
>>>>> "min < 0U".
>> 225             if((max >= d_twox*d_numchans) || (min < 0)) {
>> 226               throw
>> std::invalid_argument("pfb_synthesizer_ccf_impl::set_channel_map: map
>> range out of bounds.\n");
>> 227             }
>> 228             d_channel_map = map;
>> 229
>> 230             // Zero out fft buffer so that unused channels are always 0
>>
>> _______________________________________________
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> 
>