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

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

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.

> Anyway, I certainly also won't object this patch, so in case
> anybody wants to merge it:
> 
> Acked-by: Thomas Huth <thuth@redhat.com>
>