[Sanitizer] Plug a leak in POSIXSymbolizer::FindModuleForAddress

It was happening when we looked up a PC for a module that was dlopen'ed/dlclose'd
after the last time we fetched the list of modules

Reviewed at http://reviews.llvm.org/D8618

llvm-svn: 233257

2 files changed, 6 insertions, 6 deletions

diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_common.h b/compiler-rt/lib/sanitizer_common/sanitizer_common.h
index a4a004c3b0e..0dfa8159345 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_common.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_common.h
@@ -548,6 +548,7 @@ uptr InternalBinarySearch(const Container &v, uptr first, uptr last,
 // executable or a shared object).
 class LoadedModule {
  public:
+  LoadedModule() : full_name_(nullptr), base_address_(0) {}
   LoadedModule(const char *module_name, uptr base_address);
   void clear();
   void addAddressRange(uptr beg, uptr end, bool executable);
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_symbolizer_posix_libcdep.cc b/compiler-rt/lib/sanitizer_common/sanitizer_symbolizer_posix_libcdep.cc
index 78c189497a5..189b0abd86d 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_symbolizer_posix_libcdep.cc
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_symbolizer_posix_libcdep.cc
@@ -352,7 +352,7 @@ class InternalSymbolizer : public SymbolizerTool {
 class POSIXSymbolizer : public Symbolizer {
  public:
   explicit POSIXSymbolizer(IntrusiveList<SymbolizerTool> tools)
-      : Symbolizer(tools) {}
+      : Symbolizer(tools), n_modules_(0), modules_fresh_(false) {}
 
  private:
   const char *PlatformDemangle(const char *name) override {
@@ -368,10 +368,9 @@ class POSIXSymbolizer : public Symbolizer {
 
   LoadedModule *FindModuleForAddress(uptr address) {
     bool modules_were_reloaded = false;
-    if (modules_ == 0 || !modules_fresh_) {
-      modules_ = (LoadedModule*)(symbolizer_allocator_.Allocate(
-          kMaxNumberOfModuleContexts * sizeof(LoadedModule)));
-      CHECK(modules_);
+    if (!modules_fresh_) {
+      for (uptr i = 0; i < n_modules_; i++)
+        modules_[i].clear();
       n_modules_ = GetListOfModules(modules_, kMaxNumberOfModuleContexts,
                                     /* filter */ 0);
       CHECK_GT(n_modules_, 0);
@@ -408,7 +407,7 @@ class POSIXSymbolizer : public Symbolizer {
 
   // 16K loaded modules should be enough for everyone.
   static const uptr kMaxNumberOfModuleContexts = 1 << 14;
-  LoadedModule *modules_;  // Array of module descriptions is leaked.
+  LoadedModule modules_[kMaxNumberOfModuleContexts];
   uptr n_modules_;
   // If stale, need to reload the modules before looking up addresses.
   bool modules_fresh_;