[tsan] Allow unloading of ignored libraries

compiler-rt/lib/sanitizer_common/sanitizer_libignore.cpp

@@ -32,7 +32,7 @@ void LibIgnore::AddIgnoredLibrary(const char *name_templ) {
   lib->templ = internal_strdup(name_templ);
   lib->name = nullptr;
   lib->real_name = nullptr;
-  lib->loaded = false;
+  lib->range_id = kInvalidCodeRangeId;
 }
 
 void LibIgnore::OnLibraryLoaded(const char *name) {
@@ -43,7 +43,7 @@ void LibIgnore::OnLibraryLoaded(const char *name) {
       buf[0]) {
     for (uptr i = 0; i < count_; i++) {
       Lib *lib = &libs_[i];
-      if (!lib->loaded && (!lib->real_name) &&
+      if (!lib->loaded() && (!lib->real_name) &&
           TemplateMatch(lib->templ, name))
         lib->real_name = internal_strdup(buf.data());
     }
@@ -70,28 +70,31 @@ void LibIgnore::OnLibraryLoaded(const char *name) {
           Die();
         }
         loaded = true;
-        if (lib->loaded)
+        if (lib->loaded())
           continue;
         VReport(1,
                 "Matched called_from_lib suppression '%s' against library"
                 " '%s'\n",
                 lib->templ, mod.full_name());
-        lib->loaded = true;
         lib->name = internal_strdup(mod.full_name());
         const uptr idx =
             atomic_load(&ignored_ranges_count_, memory_order_relaxed);
         CHECK_LT(idx, ARRAY_SIZE(ignored_code_ranges_));
-        ignored_code_ranges_[idx].begin = range.beg;
-        ignored_code_ranges_[idx].end = range.end;
+        ignored_code_ranges_[idx].OnLoad(range.beg, range.end);
+        // Record the index of the ignored range.
+        lib->range_id = idx;
         atomic_store(&ignored_ranges_count_, idx + 1, memory_order_release);
         break;
       }
     }
-    if (lib->loaded && !loaded) {
-      Report("%s: library '%s' that was matched against called_from_lib"
-             " suppression '%s' is unloaded\n",
-             SanitizerToolName, lib->name, lib->templ);
-      Die();
+    if (lib->loaded() && !loaded) {
+      VReport(1,
+              "%s: library '%s' that was matched against called_from_lib"
+              " suppression '%s' is unloaded\n",
+              SanitizerToolName, lib->name, lib->templ);
+      // The library is unloaded so mark the ignored code range as unloaded.
+      ignored_code_ranges_[lib->range_id].OnUnload();
+      lib->range_id = kInvalidCodeRangeId;
     }
   }
 
@@ -110,8 +113,7 @@ void LibIgnore::OnLibraryLoaded(const char *name) {
         const uptr idx =
             atomic_load(&instrumented_ranges_count_, memory_order_relaxed);
         CHECK_LT(idx, ARRAY_SIZE(instrumented_code_ranges_));
-        instrumented_code_ranges_[idx].begin = range.beg;
-        instrumented_code_ranges_[idx].end = range.end;
+        instrumented_code_ranges_[idx].OnLoad(range.beg, range.end);
         atomic_store(&instrumented_ranges_count_, idx + 1,
                      memory_order_release);
       }

compiler-rt/lib/sanitizer_common/sanitizer_libignore.h

@@ -49,25 +49,36 @@ class LibIgnore {
   bool IsPcInstrumented(uptr pc) const;
 
  private:
+  static const uptr kMaxIgnoredRanges = 128;
+  static const uptr kMaxInstrumentedRanges = 1024;
+  static const uptr kMaxLibs = 1024;
+  static const uptr kInvalidCodeRangeId = -1;
+
   struct Lib {
     char *templ;
     char *name;
     char *real_name;  // target of symlink
-    bool loaded;
+    uptr range_id;
+    bool loaded() const { return range_id != kInvalidCodeRangeId; };
   };
 
   struct LibCodeRange {
-    uptr begin;
-    uptr end;
-  };
+    bool IsInRange(uptr pc) const {
+      return (pc >= begin && pc < atomic_load(&end, memory_order_acquire));
+    }
 
-  inline bool IsInRange(uptr pc, const LibCodeRange &range) const {
-    return (pc >= range.begin && pc < range.end);
-  }
+    void OnLoad(uptr b, uptr e) {
+      begin = b;
+      atomic_store(&end, e, memory_order_release);
+    }
 
-  static const uptr kMaxIgnoredRanges = 128;
-  static const uptr kMaxInstrumentedRanges = 1024;
-  static const uptr kMaxLibs = 1024;
+    void OnUnload() { atomic_store(&end, 0, memory_order_release); }
+
+   private:
+    uptr begin;
+    // A value of 0 means the associated module was unloaded.
+    atomic_uintptr_t end;
+  };
 
   // Hot part:
   atomic_uintptr_t ignored_ranges_count_;
@@ -90,7 +101,7 @@ class LibIgnore {
 inline bool LibIgnore::IsIgnored(uptr pc, bool *pc_in_ignored_lib) const {
   const uptr n = atomic_load(&ignored_ranges_count_, memory_order_acquire);
   for (uptr i = 0; i < n; i++) {
-    if (IsInRange(pc, ignored_code_ranges_[i])) {
+    if (ignored_code_ranges_[i].IsInRange(pc)) {
       *pc_in_ignored_lib = true;
       return true;
     }
@@ -104,7 +115,7 @@ inline bool LibIgnore::IsIgnored(uptr pc, bool *pc_in_ignored_lib) const {
 inline bool LibIgnore::IsPcInstrumented(uptr pc) const {
   const uptr n = atomic_load(&instrumented_ranges_count_, memory_order_acquire);
   for (uptr i = 0; i < n; i++) {
-    if (IsInRange(pc, instrumented_code_ranges_[i]))
+    if (instrumented_code_ranges_[i].IsInRange(pc))
       return true;
   }
   return false;

compiler-rt/test/tsan/ignore_lib3.cpp

@@ -3,10 +3,10 @@
 
 // RUN: %clangxx_tsan -O1 %s -DLIB -fPIC -fno-sanitize=thread -shared -o %t-dir/libignore_lib3.so
 // RUN: %clangxx_tsan -O1 %s %link_libcxx_tsan -o %t-dir/executable
-// RUN: %env_tsan_opts=suppressions='%s.supp' %deflake %run %t-dir/executable | FileCheck %s
+// RUN: %env_tsan_opts=suppressions='%s.supp':verbosity=1 %run %t-dir/executable 2>&1 | FileCheck %s
 
 // Tests that unloading of a library matched against called_from_lib suppression
-// causes program crash (this is not supported).
+// is supported.
 
 // Some aarch64 kernels do not support non executable write pages
 // REQUIRES: stable-runtime
@@ -22,18 +22,30 @@
 
 int main(int argc, char **argv) {
   std::string lib = std::string(dirname(argv[0])) + "/libignore_lib3.so";
-  void *h = dlopen(lib.c_str(), RTLD_GLOBAL | RTLD_NOW);
-  dlclose(h);
+  void *h;
+  void (*f)();
+  // Try opening, closing and reopening the ignored lib.
+  for (unsigned int k = 0; k < 2; k++) {
+    h = dlopen(lib.c_str(), RTLD_GLOBAL | RTLD_NOW);
+    if (h == 0)
+      exit(printf("failed to load the library (%d)\n", errno));
+    f = (void (*)())dlsym(h, "libfunc");
+    if (f == 0)
+      exit(printf("failed to find the func (%d)\n", errno));
+    f();
+    dlclose(h);
+  }
   fprintf(stderr, "OK\n");
 }
 
 #else  // #ifdef LIB
 
-extern "C" void libfunc() {
-}
+#  include "ignore_lib_lib.h"
 
 #endif  // #ifdef LIB
 
-// CHECK: ThreadSanitizer: library {{.*}} that was matched against called_from_lib suppression 'ignore_lib3.so' is unloaded
-// CHECK-NOT: OK
-
+// CHECK: Matched called_from_lib suppression 'ignore_lib3.so'
+// CHECK: library '{{.*}}ignore_lib3.so' that was matched against called_from_lib suppression 'ignore_lib3.so' is unloaded
+// CHECK: Matched called_from_lib suppression 'ignore_lib3.so'
+// CHECK: library '{{.*}}ignore_lib3.so' that was matched against called_from_lib suppression 'ignore_lib3.so' is unloaded
+// CHECK: OK