[compiler-rt] r354092 - [libFuzzer] print new functions as they are discovered in the fork mode

Kostya Serebryany via llvm-commits llvm-commits at lists.llvm.org
Fri Feb 15 10:50:10 PST 2019


Hi Diana,

I am not sure how to interpret these bot failures...
Can you tell which test times out?

The only tests that can be affected by this change pass:

PASS: libFuzzer :: merge.test (48757 of 48763)

PASS: libFuzzer :: fork.test (48754 of 48763)

(let me revive my aarch64 development box and see it myself)








On Fri, Feb 15, 2019 at 4:22 AM Diana Picus <diana.picus at linaro.org> wrote:

> Hi Kostya,
>
> It seems that this is causing the tests to hang on AArch64:
> http://lab.llvm.org:8011/builders/clang-cmake-aarch64-full/builds/6571
> http://lab.llvm.org:8011/builders/clang-cmake-aarch64-lld/builds/6038
>
> It might have something to do with cxa_atexit_race, since I saw it
> running for about 8 minutes on one of the machines.
>
> Could you please have a look?
>
> Thanks,
> Diana
>
> On Fri, 15 Feb 2019 at 02:21, Kostya Serebryany via llvm-commits
> <llvm-commits at lists.llvm.org> wrote:
> >
> > Author: kcc
> > Date: Thu Feb 14 17:22:00 2019
> > New Revision: 354092
> >
> > URL: http://llvm.org/viewvc/llvm-project?rev=354092&view=rev
> > Log:
> > [libFuzzer] print new functions as they are discovered in the fork mode
> >
> > Modified:
> >     compiler-rt/trunk/lib/fuzzer/FuzzerFork.cpp
> >     compiler-rt/trunk/lib/fuzzer/FuzzerMerge.cpp
> >     compiler-rt/trunk/lib/fuzzer/FuzzerTracePC.cpp
> >     compiler-rt/trunk/lib/fuzzer/FuzzerTracePC.h
> >
> > Modified: compiler-rt/trunk/lib/fuzzer/FuzzerFork.cpp
> > URL:
> http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/fuzzer/FuzzerFork.cpp?rev=354092&r1=354091&r2=354092&view=diff
> >
> ==============================================================================
> > --- compiler-rt/trunk/lib/fuzzer/FuzzerFork.cpp (original)
> > +++ compiler-rt/trunk/lib/fuzzer/FuzzerFork.cpp Thu Feb 14 17:22:00 2019
> > @@ -13,6 +13,7 @@
> >  #include "FuzzerIO.h"
> >  #include "FuzzerMerge.h"
> >  #include "FuzzerSHA1.h"
> > +#include "FuzzerTracePC.h"
> >  #include "FuzzerUtil.h"
> >
> >  #include <atomic>
> > @@ -86,11 +87,13 @@ struct GlobalEnv {
> >        Cmd.removeArgument(C);
> >      Cmd.addFlag("reload", "0");  // working in an isolated dir, no
> reload.
> >      Cmd.addFlag("print_final_stats", "1");
> > +    Cmd.addFlag("print_funcs", "0");  // no need to spend time
> symbolizing.
> >      Cmd.addFlag("max_total_time", std::to_string(std::min((size_t)300,
> JobId)));
> >
> >      auto Job = new FuzzJob;
> >      std::string Seeds;
> > -    if (size_t CorpusSubsetSize = std::min(Files.size(), (size_t)100))
> > +    if (size_t CorpusSubsetSize =
> > +            std::min(Files.size(), (size_t)sqrt(Files.size() + 2)))
> >        for (size_t i = 0; i < CorpusSubsetSize; i++)
> >          Seeds += (Seeds.empty() ? "" : ",") +
> >                   Files[Rand->SkewTowardsLast(Files.size())];
> > @@ -135,6 +138,12 @@ struct GlobalEnv {
> >      RmDirRecursive(Job->CorpusDir);
> >      Features.insert(NewFeatures.begin(), NewFeatures.end());
> >      Cov.insert(NewCov.begin(), NewCov.end());
> > +    for (auto Idx : NewCov)
> > +      if (auto *TE = TPC.PCTableEntryByIdx(Idx))
> > +        if (TPC.PcIsFuncEntry(TE))
> > +          PrintPC("  NEW_FUNC: %p %F %L\n", "",
> > +                  TPC.GetNextInstructionPc(TE->PC));
> > +
> >      auto Stats = ParseFinalStatsFromLog(Job->LogPath);
> >      NumRuns += Stats.number_of_executed_units;
> >      if (!FilesToAdd.empty())
> >
> > Modified: compiler-rt/trunk/lib/fuzzer/FuzzerMerge.cpp
> > URL:
> http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/fuzzer/FuzzerMerge.cpp?rev=354092&r1=354091&r2=354092&view=diff
> >
> ==============================================================================
> > --- compiler-rt/trunk/lib/fuzzer/FuzzerMerge.cpp (original)
> > +++ compiler-rt/trunk/lib/fuzzer/FuzzerMerge.cpp Thu Feb 14 17:22:00 2019
> > @@ -100,7 +100,7 @@ bool Merger::Parse(std::istream &IS, boo
> >        LastSeenStartMarker = kInvalidStartMarker;
> >        if (ParseCoverage) {
> >          TmpFeatures.clear();  // use a vector from outer scope to avoid
> resizes.
> > -        while (ISS1 >> std::hex >> N)
> > +        while (ISS1 >> N)
> >            TmpFeatures.push_back(N);
> >          std::sort(TmpFeatures.begin(), TmpFeatures.end());
> >          Files[CurrentFileIdx].Features = TmpFeatures;
> > @@ -108,7 +108,7 @@ bool Merger::Parse(std::istream &IS, boo
> >      } else if (Marker == "COV") {
> >        size_t CurrentFileIdx = N;
> >        if (ParseCoverage)
> > -        while (ISS1 >> std::hex >> N)
> > +        while (ISS1 >> N)
> >            if (PCs.insert(N).second)
> >              Files[CurrentFileIdx].Cov.push_back(N);
> >      } else {
> > @@ -220,7 +220,7 @@ void Fuzzer::CrashResistantMergeInternal
> >      }
> >      std::ostringstream StartedLine;
> >      // Write the pre-run marker.
> > -    OF << "STARTED " << std::dec << i << " " << U.size() << "\n";
> > +    OF << "STARTED " << i << " " << U.size() << "\n";
> >      OF.flush();  // Flush is important since Command::Execute may crash.
> >      // Run.
> >      TPC.ResetMaps();
> > @@ -242,9 +242,9 @@ void Fuzzer::CrashResistantMergeInternal
> >      // Write the post-run marker and the coverage.
> >      OF << "FT " << i;
> >      for (size_t F : UniqFeatures)
> > -      OF << " " << std::hex << F;
> > +      OF << " " << F;
> >      OF << "\n";
> > -    OF << "COV " << std::dec << i;
> > +    OF << "COV " << i;
> >      TPC.ForEachObservedPC([&](const TracePC::PCTableEntry *TE) {
> >        if (AllPCs.insert(TE).second)
> >          OF << " " << TPC.PCTableEntryIdx(TE);
> >
> > Modified: compiler-rt/trunk/lib/fuzzer/FuzzerTracePC.cpp
> > URL:
> http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/fuzzer/FuzzerTracePC.cpp?rev=354092&r1=354091&r2=354092&view=diff
> >
> ==============================================================================
> > --- compiler-rt/trunk/lib/fuzzer/FuzzerTracePC.cpp (original)
> > +++ compiler-rt/trunk/lib/fuzzer/FuzzerTracePC.cpp Thu Feb 14 17:22:00
> 2019
> > @@ -174,7 +174,7 @@ inline ALWAYS_INLINE uintptr_t GetPrevio
> >
> >  /// \return the address of the next instruction.
> >  /// Note: the logic is copied from
> `sanitizer_common/sanitizer_stacktrace.cc`
> > -inline ALWAYS_INLINE uintptr_t GetNextInstructionPc(uintptr_t PC) {
> > +ALWAYS_INLINE uintptr_t TracePC::GetNextInstructionPc(uintptr_t PC) {
> >  #if defined(__mips__)
> >    return PC + 8;
> >  #elif defined(__powerpc__) || defined(__sparc__) || defined(__arm__) ||
> \
> > @@ -196,7 +196,7 @@ void TracePC::UpdateObservedPCs() {
> >    };
> >
> >    auto Observe = [&](const PCTableEntry *TE) {
> > -    if (TE->PCFlags & 1)
> > +    if (PcIsFuncEntry(TE))
> >        if (++ObservedFuncs[TE->PC] == 1 && NumPrintNewFuncs)
> >          CoveredFuncs.push_back(TE->PC);
> >      ObservePC(TE);
> > @@ -239,6 +239,16 @@ uintptr_t TracePC::PCTableEntryIdx(const
> >    return 0;
> >  }
> >
> > +const TracePC::PCTableEntry *TracePC::PCTableEntryByIdx(uintptr_t Idx) {
> > +  for (size_t i = 0; i < NumPCTables; i++) {
> > +    auto &M = ModulePCTable[i];
> > +    size_t Size = M.Stop - M.Start;
> > +    if (Idx < Size) return &M.Start[Idx];
> > +    Idx -= Size;
> > +  }
> > +  return nullptr;
> > +}
> > +
> >  static std::string GetModuleName(uintptr_t PC) {
> >    char ModulePathRaw[4096] = "";  // What's PATH_MAX in portable C++?
> >    void *OffsetRaw = nullptr;
> > @@ -257,10 +267,10 @@ void TracePC::IterateCoveredFunctions(Ca
> >      auto ModuleName = GetModuleName(M.Start->PC);
> >      for (auto NextFE = M.Start; NextFE < M.Stop; ) {
> >        auto FE = NextFE;
> > -      assert((FE->PCFlags & 1) && "Not a function entry point");
> > +      assert(PcIsFuncEntry(FE) && "Not a function entry point");
> >        do {
> >          NextFE++;
> > -      } while (NextFE < M.Stop && !(NextFE->PCFlags & 1));
> > +      } while (NextFE < M.Stop && !(PcIsFuncEntry(NextFE)));
> >        CB(FE, NextFE, ObservedFuncs[FE->PC]);
> >      }
> >    }
> > @@ -275,7 +285,7 @@ void TracePC::SetFocusFunction(const std
> >      auto &PCTE = ModulePCTable[M];
> >      size_t N = PCTE.Stop - PCTE.Start;
> >      for (size_t I = 0; I < N; I++) {
> > -      if (!(PCTE.Start[I].PCFlags & 1)) continue;  // not a function
> entry.
> > +      if (!(PcIsFuncEntry(&PCTE.Start[I]))) continue;  // not a
> function entry.
> >        auto Name = DescribePC("%F",
> GetNextInstructionPc(PCTE.Start[I].PC));
> >        if (Name[0] == 'i' && Name[1] == 'n' && Name[2] == ' ')
> >          Name = Name.substr(3, std::string::npos);
> >
> > Modified: compiler-rt/trunk/lib/fuzzer/FuzzerTracePC.h
> > URL:
> http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/fuzzer/FuzzerTracePC.h?rev=354092&r1=354091&r2=354092&view=diff
> >
> ==============================================================================
> > --- compiler-rt/trunk/lib/fuzzer/FuzzerTracePC.h (original)
> > +++ compiler-rt/trunk/lib/fuzzer/FuzzerTracePC.h Thu Feb 14 17:22:00 2019
> > @@ -127,6 +127,9 @@ class TracePC {
> >    };
> >
> >    uintptr_t PCTableEntryIdx(const PCTableEntry *TE);
> > +  const PCTableEntry *PCTableEntryByIdx(uintptr_t Idx);
> > +  static uintptr_t GetNextInstructionPc(uintptr_t PC);
> > +  bool PcIsFuncEntry(const PCTableEntry *TE) { return TE->PCFlags & 1; }
> >
> >  private:
> >    bool UseCounters = false;
> >
> >
> > _______________________________________________
> > llvm-commits mailing list
> > llvm-commits at lists.llvm.org
> > https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
>
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