[llvm] r228170 - [fuzzer] make multi-process execution more verbose; fix mutation to actually respect mutation depth and to never produce empty units

Kostya Serebryany kcc at google.com
Wed Feb 4 18:07:27 PST 2015


Ouch indeed. :(

On Wed, Feb 4, 2015 at 12:48 PM, David Blaikie <dblaikie at gmail.com> wrote:

>
>
> On Wed, Feb 4, 2015 at 12:44 PM, Sean Silva <chisophugis at gmail.com> wrote:
>
>> -    bool MutateDepth = 10;
>> +    int  MutateDepth = 5;
>>
>> Ouch, I feel like we should maybe have a warning for this?
>>
>
> Agreed - we do have -Wliteral-conversion which catches some cases like
> this, but I don't think it catches cases where the destination is bool,
> unfortunately. I think I tried to improve this years ago & it was more work
> than I had time for, at the time.
>
> - David
>
>
>>
>> -- Sean Silva
>>
>> On Wed, Feb 4, 2015 at 11:10 AM, Kostya Serebryany <kcc at google.com>
>> wrote:
>>
>>> Author: kcc
>>> Date: Wed Feb  4 13:10:20 2015
>>> New Revision: 228170
>>>
>>> URL: http://llvm.org/viewvc/llvm-project?rev=228170&view=rev
>>> Log:
>>> [fuzzer] make multi-process execution more verbose; fix mutation to
>>> actually respect mutation depth and to never produce empty units
>>>
>>> Modified:
>>>     llvm/trunk/lib/Fuzzer/FuzzerFlags.def
>>>     llvm/trunk/lib/Fuzzer/FuzzerIO.cpp
>>>     llvm/trunk/lib/Fuzzer/FuzzerInternal.h
>>>     llvm/trunk/lib/Fuzzer/FuzzerLoop.cpp
>>>     llvm/trunk/lib/Fuzzer/FuzzerMain.cpp
>>>     llvm/trunk/lib/Fuzzer/FuzzerMutate.cpp
>>>
>>> Modified: llvm/trunk/lib/Fuzzer/FuzzerFlags.def
>>> URL:
>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Fuzzer/FuzzerFlags.def?rev=228170&r1=228169&r2=228170&view=diff
>>>
>>> ==============================================================================
>>> --- llvm/trunk/lib/Fuzzer/FuzzerFlags.def (original)
>>> +++ llvm/trunk/lib/Fuzzer/FuzzerFlags.def Wed Feb  4 13:10:20 2015
>>> @@ -16,7 +16,7 @@ FUZZER_FLAG(int, iterations, -1,
>>>              "Number of iterations of the fuzzer (-1 for infinite
>>> runs).")
>>>  FUZZER_FLAG(int, max_len, 64, "Maximal length of the test input.")
>>>  FUZZER_FLAG(int, cross_over, 1, "If 1, cross over inputs.")
>>> -FUZZER_FLAG(int, mutate_depth, 10,
>>> +FUZZER_FLAG(int, mutate_depth, 5,
>>>              "Apply this number of consecutive mutations to each input.")
>>>  FUZZER_FLAG(int, exit_on_first, 0,
>>>              "If 1, exit after the first new interesting input is
>>> found.")
>>>
>>> Modified: llvm/trunk/lib/Fuzzer/FuzzerIO.cpp
>>> URL:
>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Fuzzer/FuzzerIO.cpp?rev=228170&r1=228169&r2=228170&view=diff
>>>
>>> ==============================================================================
>>> --- llvm/trunk/lib/Fuzzer/FuzzerIO.cpp (original)
>>> +++ llvm/trunk/lib/Fuzzer/FuzzerIO.cpp Wed Feb  4 13:10:20 2015
>>> @@ -9,6 +9,8 @@
>>>  // IO functions.
>>>
>>>  //===----------------------------------------------------------------------===//
>>>  #include "FuzzerInternal.h"
>>> +#include <iostream>
>>> +#include <iterator>
>>>  #include <fstream>
>>>  #include <dirent.h>
>>>  namespace fuzzer {
>>> @@ -31,6 +33,12 @@ Unit FileToVector(const std::string &Pat
>>>                std::istreambuf_iterator<char>());
>>>  }
>>>
>>> +void CopyFileToErr(const std::string &Path) {
>>> +  std::ifstream T(Path);
>>> +  std::copy(std::istreambuf_iterator<char>(T),
>>> std::istreambuf_iterator<char>(),
>>> +            std::ostream_iterator<char>(std::cerr, ""));
>>> +}
>>> +
>>>  void WriteToFile(const Unit &U, const std::string &Path) {
>>>    std::ofstream OF(Path);
>>>    OF.write((const char*)U.data(), U.size());
>>>
>>> Modified: llvm/trunk/lib/Fuzzer/FuzzerInternal.h
>>> URL:
>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Fuzzer/FuzzerInternal.h?rev=228170&r1=228169&r2=228170&view=diff
>>>
>>> ==============================================================================
>>> --- llvm/trunk/lib/Fuzzer/FuzzerInternal.h (original)
>>> +++ llvm/trunk/lib/Fuzzer/FuzzerInternal.h Wed Feb  4 13:10:20 2015
>>> @@ -23,6 +23,7 @@ using namespace std::chrono;
>>>  Unit ReadFile(const char *Path);
>>>  void ReadDirToVectorOfUnits(const char *Path, std::vector<Unit> *V);
>>>  void WriteToFile(const Unit &U, const std::string &Path);
>>> +void CopyFileToErr(const std::string &Path);
>>>  // Returns "Dir/FileName" or equivalent for the current OS.
>>>  std::string DirPlusFile(const std::string &DirPath,
>>>                          const std::string &FileName);
>>> @@ -42,7 +43,7 @@ class Fuzzer {
>>>      int Verbosity = 1;
>>>      int MaxLen = 0;
>>>      bool DoCrossOver = true;
>>> -    bool MutateDepth = 10;
>>> +    int  MutateDepth = 5;
>>>      bool ExitOnFirst = false;
>>>      bool UseFullCoverageSet  = false;
>>>      std::string OutputCorpus;
>>>
>>> Modified: llvm/trunk/lib/Fuzzer/FuzzerLoop.cpp
>>> URL:
>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Fuzzer/FuzzerLoop.cpp?rev=228170&r1=228169&r2=228170&view=diff
>>>
>>> ==============================================================================
>>> --- llvm/trunk/lib/Fuzzer/FuzzerLoop.cpp (original)
>>> +++ llvm/trunk/lib/Fuzzer/FuzzerLoop.cpp Wed Feb  4 13:10:20 2015
>>> @@ -146,9 +146,8 @@ void Fuzzer::SaveCorpus() {
>>>
>>>  size_t Fuzzer::MutateAndTestOne(Unit *U) {
>>>    size_t NewUnits = 0;
>>> -  for (size_t i = 0; i < Options.MutateDepth; i++) {
>>> +  for (int i = 0; i < Options.MutateDepth; i++) {
>>>      Mutate(U, Options.MaxLen);
>>> -    if (U->empty()) continue;
>>>      size_t NewCoverage = RunOne(*U);
>>>      if (NewCoverage) {
>>>        Corpus.push_back(*U);
>>> @@ -158,6 +157,7 @@ size_t Fuzzer::MutateAndTestOne(Unit *U)
>>>                    << "\tNEW: " << NewCoverage
>>>                    << " L: " << U->size()
>>>                    << " S: " << Corpus.size()
>>> +                  << " I: " << i
>>>                    << "\t";
>>>          if (U->size() < 30) {
>>>            PrintASCII(*U);
>>>
>>> Modified: llvm/trunk/lib/Fuzzer/FuzzerMain.cpp
>>> URL:
>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Fuzzer/FuzzerMain.cpp?rev=228170&r1=228169&r2=228170&view=diff
>>>
>>> ==============================================================================
>>> --- llvm/trunk/lib/Fuzzer/FuzzerMain.cpp (original)
>>> +++ llvm/trunk/lib/Fuzzer/FuzzerMain.cpp Wed Feb  4 13:10:20 2015
>>> @@ -17,6 +17,7 @@
>>>  #include <iostream>
>>>  #include <thread>
>>>  #include <atomic>
>>> +#include <mutex>
>>>
>>>  // ASAN options:
>>>  //   * don't dump the coverage to disk.
>>> @@ -105,20 +106,30 @@ static void ParseFlags(int argc, char **
>>>  }
>>>
>>>  static void WorkerThread(const std::string &Cmd, std::atomic<int>
>>> *Counter,
>>> -                         int NumJobs) {
>>> +                        int NumJobs, std::atomic<bool> *HasErrors) {
>>> +  static std::mutex CerrMutex;
>>>    while (true) {
>>>      int C = (*Counter)++;
>>> -    if (C >= NumJobs) return;
>>> -    std::string ToRun = Cmd + " > fuzz-" + std::to_string(C) + ".log
>>> 2>&1\n";
>>> +    if (C >= NumJobs) break;
>>> +    std::string Log = "fuzz-" + std::to_string(C) + ".log";
>>> +    std::string ToRun = Cmd + " > " + Log + " 2>&1\n";
>>>      if (Flags.verbosity)
>>>        std::cerr << ToRun;
>>> -    system(ToRun.c_str());
>>> +    int ExitCode = system(ToRun.c_str());
>>> +    if (ExitCode != 0)
>>> +      *HasErrors = true;
>>> +    std::lock_guard<std::mutex> Lock(CerrMutex);
>>> +    std::cerr << "================== Job " << C
>>> +              << " exited with exit code " << ExitCode
>>> +              << " =================\n";
>>> +    fuzzer::CopyFileToErr(Log);
>>>    }
>>>  }
>>>
>>>  static int RunInMultipleProcesses(int argc, char **argv, int NumWorkers,
>>>                                    int NumJobs) {
>>>    std::atomic<int> Counter(0);
>>> +  std::atomic<bool> HasErrors(false);
>>>    std::string Cmd;
>>>    for (int i = 0; i < argc; i++) {
>>>      if (FlagValue(argv[i], "jobs") || FlagValue(argv[i], "workers"))
>>> continue;
>>> @@ -127,10 +138,10 @@ static int RunInMultipleProcesses(int ar
>>>    }
>>>    std::vector<std::thread> V;
>>>    for (int i = 0; i < NumWorkers; i++)
>>> -    V.push_back(std::thread(WorkerThread, Cmd, &Counter, NumJobs));
>>> +    V.push_back(std::thread(WorkerThread, Cmd, &Counter, NumJobs,
>>> &HasErrors));
>>>    for (auto &T : V)
>>>      T.join();
>>> -  return 0;
>>> +  return HasErrors ? 1 : 0;
>>>  }
>>>
>>>  int main(int argc, char **argv) {
>>>
>>> Modified: llvm/trunk/lib/Fuzzer/FuzzerMutate.cpp
>>> URL:
>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Fuzzer/FuzzerMutate.cpp?rev=228170&r1=228169&r2=228170&view=diff
>>>
>>> ==============================================================================
>>> --- llvm/trunk/lib/Fuzzer/FuzzerMutate.cpp (original)
>>> +++ llvm/trunk/lib/Fuzzer/FuzzerMutate.cpp Wed Feb  4 13:10:20 2015
>>> @@ -31,18 +31,25 @@ static char RandCh() {
>>>    return Special[rand() % (sizeof(Special) - 1)];
>>>  }
>>>
>>> +// Mutate U in place.
>>>  void Mutate(Unit *U, size_t MaxLen) {
>>>    assert(MaxLen > 0);
>>>    assert(U->size() <= MaxLen);
>>> +  if (U->empty()) {
>>> +    for (size_t i = 0; i < MaxLen; i++)
>>> +      U->push_back(RandCh());
>>> +    return;
>>> +  }
>>> +  assert(!U->empty());
>>>    switch (rand() % 3) {
>>>    case 0:
>>> -    if (U->size())
>>> +    if (U->size() > 1) {
>>>        U->erase(U->begin() + rand() % U->size());
>>> -    break;
>>> +      break;
>>> +    }
>>> +    // Fallthrough
>>>    case 1:
>>> -    if (U->empty()) {
>>> -      U->push_back(RandCh());
>>> -    } else if (U->size() < MaxLen) {
>>> +    if (U->size() < MaxLen) {
>>>        U->insert(U->begin() + rand() % U->size(), RandCh());
>>>      } else { // At MaxLen.
>>>        uint8_t Ch = RandCh();
>>> @@ -51,12 +58,13 @@ void Mutate(Unit *U, size_t MaxLen) {
>>>      }
>>>      break;
>>>    default:
>>> -    if (!U->empty()) {
>>> -      size_t idx = rand() % U->size();
>>> -      (*U)[idx] = FlipRandomBit((*U)[idx]);
>>> +    {
>>> +      size_t Idx = rand() % U->size();
>>> +      (*U)[Idx] = FlipRandomBit((*U)[Idx]);
>>>      }
>>>      break;
>>>    }
>>> +  assert(!U->empty());
>>>  }
>>>
>>>  }  // namespace fuzzer
>>>
>>>
>>> _______________________________________________
>>> llvm-commits mailing list
>>> llvm-commits at cs.uiuc.edu
>>> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
>>>
>>
>>
>
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