[PATCH] D21081: MPI-Checker patch for Clang Static Analyzer

Devin Coughlin via cfe-commits cfe-commits at lists.llvm.org
Tue Jun 7 09:47:32 PDT 2016 

dcoughlin added a comment.

Here is the ASan report. It looks to me like the issue is that MPIChecker is holding on a reference to a clang::ento::BugReporter after the lifetime of the BugReporter has ended. The BugReporter lives in ExprEngine and the analyzer creates a new ExprEngine for each top-level declaration that is analyzed but uses the same Checker instances across declarations. This means it is not safe to stash a reference to the BugReporter in an instance of MPIBugReporter in an instance of MPIChecker.




18751==ERROR: AddressSanitizer: stack-use-after-return on address 0x7f0c695ebc70 at pc 0x00000867b44c bp 0x7ffe3b01d6f0 sp 0x7ffe3b01d6e8
-----------------------------------------------------------------------------------------------------------------------------------------

READ of size 8 at 0x7f0c695ebc70 thread T0

  #0 0x867b44b in getSourceManager /mnt/b/sanitizer-buildbot3/sanitizer-x86_64-linux-fast/build/llvm/tools/clang/include/clang/StaticAnalyzer/Core/BugReporter/BugReporter.h:448:46
  #1 0x867b44b in clang::ento::BugReporter::emitReport(std::__1::unique_ptr<clang::ento::BugReport, std::__1::default_delete<clang::ento::BugReport> >) /mnt/b/sanitizer-buildbot3/sanitizer-x86_64-linux-fast/build/llvm/tools/clang/lib/StaticAnalyzer/Core/BugReporter.cpp:3240
  #2 0x8636355 in clang::ento::mpi::MPIBugReporter::reportUnmatchedWait(clang::ento::CallEvent const&, clang::ento::MemRegion const*, clang::ento::ExplodedNode const*) const /mnt/b/sanitizer-buildbot3/sanitizer-x86_64-linux-fast/build/llvm/tools/clang/lib/StaticAnalyzer/Checkers/MPI-Checker/MPIBugReporter.cpp:82:3
  #3 0x843e1ee in clang::ento::mpi::MPIChecker::checkUnmatchedWaits(clang::ento::CallEvent const&, clang::ento::CheckerContext&) const /mnt/b/sanitizer-buildbot3/sanitizer-x86_64-linux-fast/build/llvm/tools/clang/lib/StaticAnalyzer/Checkers/MPI-Checker/MPIChecker.cpp:88:7
  #4 0x8447dc8 in checkPreCall /mnt/b/sanitizer-buildbot3/sanitizer-x86_64-linux-fast/build/llvm/tools/clang/lib/StaticAnalyzer/Checkers/MPI-Checker/MPIChecker.h:36:5
  #5 0x8447dc8 in void clang::ento::check::PreCall::_checkCall<clang::ento::mpi::MPIChecker>(void*, clang::ento::CallEvent const&, clang::ento::CheckerContext&) /mnt/b/sanitizer-buildbot3/sanitizer-x86_64-linux-fast/build/llvm/tools/clang/include/clang/StaticAnalyzer/Core/Checker.h:168
  #6 0x86db2f2 in operator() /mnt/b/sanitizer-buildbot3/sanitizer-x86_64-linux-fast/build/llvm/tools/clang/include/clang/StaticAnalyzer/Core/CheckerManager.h:59:12
  #7 0x86db2f2 in runChecker /mnt/b/sanitizer-buildbot3/sanitizer-x86_64-linux-fast/build/llvm/tools/clang/lib/StaticAnalyzer/Core/CheckerManager.cpp:269
  #8 0x86db2f2 in expandGraphWithCheckers<(anonymous namespace)::CheckCallContext> /mnt/b/sanitizer-buildbot3/sanitizer-x86_64-linux-fast/build/llvm/tools/clang/lib/StaticAnalyzer/Core/CheckerManager.cpp:123
  #9 0x86db2f2 in clang::ento::CheckerManager::runCheckersForCallEvent(bool, clang::ento::ExplodedNodeSet&, clang::ento::ExplodedNodeSet const&, clang::ento::CallEvent const&, clang::ento::ExprEngine&, bool) /mnt/b/sanitizer-buildbot3/sanitizer-x86_64-linux-fast/build/llvm/tools/clang/lib/StaticAnalyzer/Core/CheckerManager.cpp:285
  #10 0x8782a84 in runCheckersForPreCall /mnt/b/sanitizer-buildbot3/sanitizer-x86_64-linux-fast/build/llvm/tools/clang/include/clang/StaticAnalyzer/Core/CheckerManager.h:252:5
  #11 0x8782a84 in clang::ento::ExprEngine::evalCall(clang::ento::ExplodedNodeSet&, clang::ento::ExplodedNode*, clang::ento::CallEvent const&) /mnt/b/sanitizer-buildbot3/sanitizer-x86_64-linux-fast/build/llvm/tools/clang/lib/StaticAnalyzer/Core/ExprEngineCallAndReturn.cpp:509
  #12 0x878205b in clang::ento::ExprEngine::VisitCallExpr(clang::CallExpr const*, clang::ento::ExplodedNode*, clang::ento::ExplodedNodeSet&) /mnt/b/sanitizer-buildbot3/sanitizer-x86_64-linux-fast/build/llvm/tools/clang/lib/StaticAnalyzer/Core/ExprEngineCallAndReturn.cpp:487:5
  #13 0x872a0d8 in clang::ento::ExprEngine::Visit(clang::Stmt const*, clang::ento::ExplodedNode*, clang::ento::ExplodedNodeSet&) /mnt/b/sanitizer-buildbot3/sanitizer-x86_64-linux-fast/build/llvm/tools/clang/lib/StaticAnalyzer/Core/ExprEngine.cpp:1104:7
  #14 0x87210bf in clang::ento::ExprEngine::ProcessStmt(clang::CFGStmt, clang::ento::ExplodedNode*) /mnt/b/sanitizer-buildbot3/sanitizer-x86_64-linux-fast/build/llvm/tools/clang/lib/StaticAnalyzer/Core/ExprEngine.cpp:448:5
  #15 0x87207ae in clang::ento::ExprEngine::processCFGElement(clang::CFGElement, clang::ento::ExplodedNode*, unsigned int, clang::ento::NodeBuilderContext*) /mnt/b/sanitizer-buildbot3/sanitizer-x86_64-linux-fast/build/llvm/tools/clang/lib/StaticAnalyzer/Core/ExprEngine.cpp:297:7
  #16 0x86fc7a6 in clang::ento::CoreEngine::HandlePostStmt(clang::CFGBlock const*, unsigned int, clang::ento::ExplodedNode*) /mnt/b/sanitizer-buildbot3/sanitizer-x86_64-linux-fast/build/llvm/tools/clang/lib/StaticAnalyzer/Core/CoreEngine.cpp:515:5
  #17 0x86fafed in clang::ento::CoreEngine::dispatchWorkItem(clang::ento::ExplodedNode*, clang::ProgramPoint, clang::ento::WorkListUnit const&) /mnt/b/sanitizer-buildbot3/sanitizer-x86_64-linux-fast/build/llvm/tools/clang/lib/StaticAnalyzer/Core/CoreEngine.cpp:274:7
  #18 0x86f9891 in clang::ento::CoreEngine::ExecuteWorkList(clang::LocationContext const*, unsigned int, llvm::IntrusiveRefCntPtr<clang::ento::ProgramState const>) /mnt/b/sanitizer-buildbot3/sanitizer-x86_64-linux-fast/build/llvm/tools/clang/lib/StaticAnalyzer/Core/CoreEngine.cpp:231:5
  #19 0x67f1ab5 in ExecuteWorkList /mnt/b/sanitizer-buildbot3/sanitizer-x86_64-linux-fast/build/llvm/tools/clang/include/clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h:109:12
  #20 0x67f1ab5 in (anonymous namespace)::AnalysisConsumer::ActionExprEngine(clang::Decl*, bool, clang::ento::ExprEngine::InliningModes, llvm::DenseSet<clang::Decl const*, llvm::DenseMapInfo<clang::Decl const*> >*) /mnt/b/sanitizer-buildbot3/sanitizer-x86_64-linux-fast/build/llvm/tools/clang/lib/StaticAnalyzer/Frontend/AnalysisConsumer.cpp:664
  #21 0x67f0ae2 in RunPathSensitiveChecks /mnt/b/sanitizer-buildbot3/sanitizer-x86_64-linux-fast/build/llvm/tools/clang/lib/StaticAnalyzer/Frontend/AnalysisConsumer.cpp:694:5
  #22 0x67f0ae2 in (anonymous namespace)::AnalysisConsumer::HandleCode(clang::Decl*, unsigned int, clang::ento::ExprEngine::InliningModes, llvm::DenseSet<clang::Decl const*, llvm::DenseMapInfo<clang::Decl const*> >*) /mnt/b/sanitizer-buildbot3/sanitizer-x86_64-linux-fast/build/llvm/tools/clang/lib/StaticAnalyzer/Frontend/AnalysisConsumer.cpp:632
  #23 0x67dc135 in HandleDeclsCallGraph /mnt/b/sanitizer-buildbot3/sanitizer-x86_64-linux-fast/build/llvm/tools/clang/lib/StaticAnalyzer/Frontend/AnalysisConsumer.cpp:495:5
  #24 0x67dc135 in (anonymous namespace)::AnalysisConsumer::HandleTranslationUnit(clang::ASTContext&) /mnt/b/sanitizer-buildbot3/sanitizer-x86_64-linux-fast/build/llvm/tools/clang/lib/StaticAnalyzer/Frontend/AnalysisConsumer.cpp:547
  #25 0x687dae4 in clang::ParseAST(clang::Sema&, bool, bool) /mnt/b/sanitizer-buildbot3/sanitizer-x86_64-linux-fast/build/llvm/tools/clang/lib/Parse/ParseAST.cpp:167:3
  #26 0x51c090b in clang::FrontendAction::Execute() /mnt/b/sanitizer-buildbot3/sanitizer-x86_64-linux-fast/build/llvm/tools/clang/lib/Frontend/FrontendAction.cpp:457:8
  #27 0x510f614 in clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) /mnt/b/sanitizer-buildbot3/sanitizer-x86_64-linux-fast/build/llvm/tools/clang/lib/Frontend/CompilerInstance.cpp:876:7
  #28 0x537fa92 in clang::ExecuteCompilerInvocation(clang::CompilerInstance*) /mnt/b/sanitizer-buildbot3/sanitizer-x86_64-linux-fast/build/llvm/tools/clang/lib/FrontendTool/ExecuteCompilerInvocation.cpp:241:18
  #29 0x8fc2f2 in cc1_main(llvm::ArrayRef<char const*>, char const*, void*) /mnt/b/sanitizer-buildbot3/sanitizer-x86_64-linux-fast/build/llvm/tools/clang/tools/driver/cc1_main.cpp:116:13
  #30 0x8f6a88 in ExecuteCC1Tool /mnt/b/sanitizer-buildbot3/sanitizer-x86_64-linux-fast/build/llvm/tools/clang/tools/driver/driver.cpp:301:12
  #31 0x8f6a88 in main /mnt/b/sanitizer-buildbot3/sanitizer-x86_64-linux-fast/build/llvm/tools/clang/tools/driver/driver.cpp:381
  #32 0x7f0c6c208f44 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x21f44)
  #33 0x816952 in _start (/mnt/b/sanitizer-buildbot3/sanitizer-x86_64-linux-fast/build/llvm_build_asan/bin/clang-3.9+0x816952)

Address 0x7f0c695ebc70 is located in stack of thread T0 at offset 1136 in frame

    #0 0x67f130f in (anonymous namespace)::AnalysisConsumer::ActionExprEngine(clang::Decl*, bool, clang::ento::ExprEngine::InliningModes, llvm::DenseSet<clang::Decl const*, llvm::DenseMapInfo<clang::Decl const*> >*) /mnt/b/sanitizer-buildbot3/sanitizer-x86_64-linux-fast/build/llvm/tools/clang/lib/StaticAnalyzer/Frontend/AnalysisConsumer.cpp:644
  
  This frame has 5 object(s):
    [32, 184) 'P.i'
    [256, 260) 'FD.i'
    [272, 296) 'ref.tmp.i'
    [336, 344) 'agg.tmp.i'
    [368, 1248) 'Eng' <== Memory access at offset 1136 is inside this variable

HINT: this may be a false positive if your program uses some custom stack unwind mechanism or swapcontext

  (longjmp and C++ exceptions *are* supported)

SUMMARY: AddressSanitizer: stack-use-after-return /mnt/b/sanitizer-buildbot3/sanitizer-x86_64-linux-fast/build/llvm/tools/clang/include/clang/StaticAnalyzer/Core/BugReporter/BugReporter.h:448:46 in getSourceManager
Shadow bytes around the buggy address:

  0x0fe20d2b5730: f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5
  0x0fe20d2b5740: f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5
  0x0fe20d2b5750: f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5
  0x0fe20d2b5760: f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5
  0x0fe20d2b5770: f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5

>0x0fe20d2b5780: f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5[f5]f5
================================================================

  0x0fe20d2b5790: f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5
  0x0fe20d2b57a0: f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5
  0x0fe20d2b57b0: f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5
  0x0fe20d2b57c0: f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5
  0x0fe20d2b57d0: f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5 f5

Shadow byte legend (one shadow byte represents 8 application bytes):

  Addressable:           00
  Partially addressable: 01 02 03 04 05 06 07 
  Heap left redzone:       fa
  Heap right redzone:      fb
  Freed heap region:       fd
  Stack left redzone:      f1
  Stack mid redzone:       f2
  Stack right redzone:     f3
  Stack partial redzone:   f4
  Stack after return:      f5
  Stack use after scope:   f8
  Global redzone:          f9
  Global init order:       f6
  Poisoned by user:        f7
  Container overflow:      fc
  Array cookie:            ac
  Intra object redzone:    bb
  ASan internal:           fe
  Left alloca redzone:     ca
  Right alloca redzone:    cb

18751==ABORTING
---------------

-

********************

Testing: 0 
FAIL: Clang :: Analysis/mpicheckernotes.cpp (317 of 9433)


================
Comment at: lib/StaticAnalyzer/Checkers/MPI-Checker/MPIChecker.h:51
@@ +50,3 @@
+
+    const_cast<std::unique_ptr<MPIBugReporter> &>(BReporter).reset(
+        new MPIBugReporter{Ctx.getBugReporter(), *this, *FuncClassifier});
----------------
This is not safe because the lifetime of the BugReporter is shorter than the lifetime of the checker. 

Instead, I would recommend creating a new instance of MPIBugReporter when reporting a bug. Since MPIBugReporter is only ever used when reporting bugs the cost of creating it each time (rather than caching it in an in instance variable) should not be an problem.

================
Comment at: lib/StaticAnalyzer/Checkers/MPI-Checker/MPIFunctionClassifier.h:26
@@ +25,3 @@
+public:
+  MPIFunctionClassifier(AnalysisManager &AM) { identifierInit(AM); }
+
----------------
Can this be changed to take an `ASTContext&` instead?


http://reviews.llvm.org/D21081

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