Re: [PATCH] gitlab-ci.yml: Only run one test-case per fuzzer

[Thomas Huth <thuth@redhat.com>]

On 02/10/2020 17.53, Philippe Mathieu-Daudé wrote:
> On 10/2/20 5:15 PM, Thomas Huth wrote:
>> On 02/10/2020 16.35, Alexander Bulekov wrote:
>>> With 1000 runs, there is a non-negligible chance that the fuzzer can
>>> trigger a crash. With this CI job, we care about catching build/runtime
>>> issues in the core fuzzing code. Actual device fuzzing takes place on
>>> oss-fuzz. For these purposes, only running one input should be
>>> sufficient.
>>>
>>> Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
>>> Suggested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
>>> ---
>>>  .gitlab-ci.yml | 2 +-
>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
>>> index a51c89554f..075c15d45c 100644
>>> --- a/.gitlab-ci.yml
>>> +++ b/.gitlab-ci.yml
>>> @@ -303,7 +303,7 @@ build-oss-fuzz:
>>>                        | grep -v slirp); do
>>>          grep "LLVMFuzzerTestOneInput" ${fuzzer} > /dev/null 2>&1 || continue ;
>>>          echo Testing ${fuzzer} ... ;
>>> -        "${fuzzer}" -runs=1000 -seed=1 || exit 1 ;
>>> +        "${fuzzer}" -runs=1 -seed=1 || exit 1 ;
>>
>> ... but we're apparently already using a fixed seed for running the
>> test, so it should be pretty much deterministic, shouldn't it? So the
>> chance that the fuzzer hits a crash here for a pre-existing problem
>> should be close to zero? ... so I'm not quite sure whether we really
>> need this?
> 
> You are right, "non-negligible chance that the fuzzer can trigger a
> crash" shouldn't be a problem. What matters is we don't waste CI
> resources, 1 run is enough to test the fuzzer is working.

Ok, considering that gitlab is currently thinking about limiting the
free CI minutes, that's a valid reason, indeed.

 Thomas