[llvm-dev] fuzzer crash (but not the good kind)

[Brian Cain via llvm-dev]

Ah, yes -- you need to clone with --recursive.

I will try the workaround though.
On Dec 3, 2015 1:12 PM, "Kostya Serebryany" <kcc at google.com> wrote:

>
>
> On Wed, Dec 2, 2015 at 7:17 PM, Brian Cain <brian.cain at gmail.com> wrote:
>
>> Kostya,
>>
>> Here's the git repo: https://bitbucket.org/ebadf/fuzzpy
>>
>> I've only tested it on arm7 and x86_64 linux, I expect there's a good
>> chance it may not work on other OSs.
>>
>> If you can build it successfully ("./build.sh", requires clang and
>> clang++ in your path), then you should run the "testemail" case like so:
>>
>>
> Does not build for me out of the box:
>
> ./build.sh: line 70: ./configure: No such file or directory
>
> I wonder if a smaller test possible here.
> Meanwhile, here is a workaround for you.
> Instead of
> SANITIZE_COV_OPTS="-fsanitize-coverage=bb,indirect-calls,8bit-counters"
> try using
> SANITIZE_COV_OPTS="-fsanitize-coverage=edge,indirect-calls"
>
>
> while true; do ITERS=1000 ./run.sh tests/build/testemail
>> tests/testemail/inputs/; done
>>
>> Let me know if you have any challenges building or running the test case.
>>
>>
>> On Tue, Dec 1, 2015 at 7:26 PM, Kostya Serebryany <kcc at google.com> wrote:
>>
>>> Hi Brian,
>>> Yes, looks like a bug in sanitizer coverage, please send the reproducer.
>>>
>>> On Tue, Dec 1, 2015 at 5:22 PM, Brian Cain <brian.cain at gmail.com> wrote:
>>>
>>>>
>>>> Kostya,
>>>>
>>>> I think I've found what looks like a reproducible bug in libFuzzer.
>>>> The code under test is built with ASan and the first ASan CHECK failure
>>>> shows fuzzer in the stack trace.  (see below)
>>>>
>>>> One of the factors that may be unique in my testing is that each
>>>> iteration can take a very long time to execute (tens or hundreds of
>>>> seconds).
>>>>
>>>> Let me know if you need more info, I think it shouldn't take much test
>>>> time to reproduce this.
>>>>
>>>> ================== Job 2 exited with exit code 256 ============
>>>> Flag: verbosity 3
>>>> Flag: use_traces 1
>>>> Flag: timeout 100
>>>> Flag: max_len 16384
>>>> Seed: 3259211893
>>>> PreferSmall: 0
>>>> #0      READ   units: 4975 exec/s: 0
>>>> #1      pulse  cov: 32410 bits: 30791 indir: 714 units: 4975 exec/s: 0
>>>> NEW0: 32410 L 13869
>>>> ==31301==AddressSanitizer CHECK failed:
>>>> /home/brian/src/fuzzpy/llvm_src/llvm/projects/compiler-rt/lib/sanitizer_common/sanitizer_coverage_libcdep.cc:467
>>>> "((n % 16)) == ((0))" (0x1, 0x0)
>>>>     #0 0x11d3b7 in __asan::AsanCheckFailed(char const*, int, char
>>>> const*, unsigned long long, unsigned long long)
>>>> /home/brian/src/fuzzpy/llvm_src/llvm/projects/compiler-rt/lib/asan/asan_rtl.cc:67:3
>>>>     #1 0x122f1f in __sanitizer::CheckFailed(char const*, int, char
>>>> const*, unsigned long long, unsigned long long)
>>>> /home/brian/src/fuzzpy/llvm_src/llvm/projects/compiler-rt/lib/sanitizer_common/sanitizer_common.cc:159:5
>>>>     #2 0x134317 in
>>>> __sanitizer::CoverageData::Update8bitCounterBitsetAndClearCounters(unsigned
>>>> char*)
>>>> /home/brian/src/fuzzpy/llvm_src/llvm/projects/compiler-rt/lib/sanitizer_common/sanitizer_coverage_libcdep.cc:467:5
>>>>     #3 0x1b7b53 in fuzzer::Fuzzer::PrepareCoverageBeforeRun()
>>>> /home/brian/src/fuzzpy/llvm_src//llvm/lib/Fuzzer/FuzzerLoop.cpp:264:5
>>>>     #4 0x1b501b in fuzzer::Fuzzer::RunOne(std::vector<unsigned char,
>>>> std::allocator<unsigned char> > const&)
>>>> /home/brian/src/fuzzpy/llvm_src//llvm/lib/Fuzzer/FuzzerLoop.cpp:212:3
>>>>     #5 0x1b6be3 in fuzzer::Fuzzer::ShuffleAndMinimize()
>>>> /home/brian/src/fuzzpy/llvm_src//llvm/lib/Fuzzer/FuzzerLoop.cpp:195:11
>>>>     #6 0x14477b in fuzzer::FuzzerDriver(std::vector<std::string,
>>>> std::allocator<std::string> > const&, fuzzer::UserSuppliedFuzzer&)
>>>> /home/brian/src/fuzzpy/llvm_src//llvm/lib/Fuzzer/FuzzerDriver.cpp:303:3
>>>>     #7 0x14183f in fuzzer::FuzzerDriver(int, char**,
>>>> fuzzer::UserSuppliedFuzzer&)
>>>> /home/brian/src/fuzzpy/llvm_src//llvm/lib/Fuzzer/FuzzerDriver.cpp:201:10
>>>>     #8 0x141427 in fuzzer::FuzzerDriver(int, char**, int (*)(unsigned
>>>> char const*, unsigned int))
>>>> /home/brian/src/fuzzpy/llvm_src//llvm/lib/Fuzzer/FuzzerDriver.cpp:196:10
>>>>     #9 0x1873e3 in main
>>>> /home/brian/src/fuzzpy/llvm_src//llvm/lib/Fuzzer/FuzzerMain.cpp:19:10
>>>>     #10 0xb6c86775 in __libc_start_main
>>>> /build/buildd/glibc-2.21/csu/libc-start.c:289
>>>>
>>>> DEATH:
>>>> artifact_prefix='./'; Test unit written to
>>>> ./crash-ec9fa023e9db127e2589d0ab4c506055e4174611
>>>>
>>>>
>>>> --
>>>> -Brian
>>>>
>>>
>>>
>>
>>
>> --
>> -Brian
>>
>
>
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