ASAN activate/deactive controls thread_local_quarantine_size_kb option.

[alekseyshl]

Summary

Bypass quarantine altogether when quarantine size is set ot zero.
Also, relax atomic load/store of quarantine parameters, the
release/acquire semantics is an overkill here.

[eugenis]

I agree that release/acquire is unnecessary here, but I'd like Dmitry to comment on that.

lib/asan/asan_activation.cc

void OverrideFromActivationFlags() {
     malloc_context_size = cf.malloc_context_size;
     poison_heap = f.poison_heap;
     coverage = cf.coverage;
     coverage_dir = cf.coverage_dir;
   }
 
   void Print() {
     Report(
-        "quarantine_size_mb %d, max_redzone %d, poison_heap %d, "
-        "malloc_context_size %d, alloc_dealloc_mismatch %d, "
-        "allocator_may_return_null %d, coverage %d, coverage_dir %s, "
-        "allocator_release_to_os_interval_ms %d\n",
-        allocator_options.quarantine_size_mb, allocator_options.max_redzone,
-        poison_heap, malloc_context_size,
+        "quarantine_size_mb %d, thread_local_quarantine_size_kb %d, "
+        "max_redzone %d, poison_heap %d, malloc_context_size %d, "
+        "alloc_dealloc_mismatch %d, allocator_may_return_null %d, coverage %d, "
+        "coverage_dir %s, allocator_release_to_os_interval_ms %d\n",
+        allocator_options.quarantine_size_mb,
+        allocator_options.thread_local_quarantine_size_kb,
+        allocator_options.max_redzone, poison_heap, malloc_context_size,
         allocator_options.alloc_dealloc_mismatch,
         allocator_options.may_return_null, coverage, coverage_dir,
         allocator_options.release_to_os_interval_ms);
   }
 } asan_deactivated_flags;
 
 static bool asan_is_deactivated;
 
void AsanDeactivate() {
 
   // Deactivate the runtime.
   SetCanPoisonMemory(false);
   SetMallocContextSize(1);
   ReInitializeCoverage(false, nullptr);
 
   AllocatorOptions disabled = asan_deactivated_flags.allocator_options;
   disabled.quarantine_size_mb = 0;
+  disabled.thread_local_quarantine_size_kb = 0;
   disabled.min_redzone = 16;  // Redzone must be at least 16 bytes long.
   disabled.max_redzone = 16;
   disabled.alloc_dealloc_mismatch = false;
   disabled.may_return_null = true;
   ReInitializeAllocator(disabled);
 
   asan_is_deactivated = true;
 }

lib/asan/asan_activation_flags.inc

 #endif
 
 // ASAN_ACTIVATION_FLAG(Type, Name)
 // See COMMON_FLAG in sanitizer_flags.inc for more details.
 
 ASAN_ACTIVATION_FLAG(int, redzone)
 ASAN_ACTIVATION_FLAG(int, max_redzone)
 ASAN_ACTIVATION_FLAG(int, quarantine_size_mb)
+ASAN_ACTIVATION_FLAG(int, thread_local_quarantine_size_kb)
 ASAN_ACTIVATION_FLAG(bool, alloc_dealloc_mismatch)
 ASAN_ACTIVATION_FLAG(bool, poison_heap)
 
 COMMON_ACTIVATION_FLAG(bool, allocator_may_return_null)
 COMMON_ACTIVATION_FLAG(int, malloc_context_size)
 COMMON_ACTIVATION_FLAG(bool, coverage)
 COMMON_ACTIVATION_FLAG(const char *, coverage_dir)
 COMMON_ACTIVATION_FLAG(int, verbosity)
 COMMON_ACTIVATION_FLAG(bool, help)
 COMMON_ACTIVATION_FLAG(s32, allocator_release_to_os_interval_ms)

lib/asan/asan_flags.cc

const u32 kDefaultThreadLocalQuarantineSizeKb =
         // It is not advised to go lower than 64Kb, otherwise quarantine batches
         // pushed from thread local quarantine to global one will create too
         // much overhead. One quarantine batch size is 8Kb and it  holds up to
         // 1021 chunk, which amounts to 1/8 memory overhead per batch when
         // thread local quarantine is set to 64Kb.
         (ASAN_LOW_MEMORY) ? 1 << 6 : FIRST_32_SECOND_64(1 << 8, 1 << 10);
     f->thread_local_quarantine_size_kb = kDefaultThreadLocalQuarantineSizeKb;
   }
+  if (f->thread_local_quarantine_size_kb == 0 && f->quarantine_size_mb > 0) {
+    Report("%s: thread_local_quarantine_size_kb can be set to 0 only when "
+           "quarantine_size_mb is set to 0\n", SanitizerToolName);
+    Die();
+  }
   if (!f->replace_str && common_flags()->intercept_strlen) {
     Report("WARNING: strlen interceptor is enabled even though replace_str=0. "
            "Use intercept_strlen=0 to disable it.");
   }
   if (!f->replace_str && common_flags()->intercept_strchr) {
     Report("WARNING: strchr* interceptors are enabled even though "
            "replace_str=0. Use intercept_strchr=0 to disable them.");
   }

lib/sanitizer_common/sanitizer_quarantine.h

  public:
   typedef QuarantineCache<Callback> Cache;
 
   explicit Quarantine(LinkerInitialized)
       : cache_(LINKER_INITIALIZED) {
   }
 
   void Init(uptr size, uptr cache_size) {
-    atomic_store(&max_size_, size, memory_order_release);
+    // Thread local quarantine size can be zero only when global quarantine size
+    // is zero (it allows us to perform just one atomic read per Put() call).
+    CHECK((size == 0 && cache_size == 0) || cache_size != 0);
+
+    atomic_store(&max_size_, size, memory_order_relaxed);
     atomic_store(&min_size_, size / 10 * 9,
-                 memory_order_release); // 90% of max size.
-    max_cache_size_ = cache_size;
+                 memory_order_relaxed);  // 90% of max size.
+    atomic_store(&max_cache_size_, cache_size, memory_order_relaxed);
   }
 
-  uptr GetSize() const { return atomic_load(&max_size_, memory_order_acquire); }
-  uptr GetCacheSize() const { return max_cache_size_; }
+  uptr GetSize() const { return atomic_load(&max_size_, memory_order_relaxed); }
+  uptr GetCacheSize() const {
+    return atomic_load(&max_cache_size_, memory_order_relaxed);
+  }
 
   void Put(Cache *c, Callback cb, Node *ptr, uptr size) {
+    uptr cache_size = GetCacheSize();
+    if (cache_size) {
       c->Enqueue(cb, ptr, size);
-    if (c->Size() > max_cache_size_)
+    } else {
+      // cache_size == 0 only when size == 0 (see Init).
+      cb.Recycle(ptr);
+    }
+    // Check cache size anyway to accommodate for runtime cache_size change.
+    if (c->Size() > cache_size)
       Drain(c, cb);
   }
 
   void NOINLINE Drain(Cache *c, Callback cb) {
     {
       SpinMutexLock l(&cache_mutex_);
       cache_.Transfer(c);
     }
     if (cache_.Size() > GetSize() && recycle_mutex_.TryLock())
       Recycle(cb);
   }
 
   void PrintStats() const {
     // It assumes that the world is stopped, just as the allocator's PrintStats.
     cache_.PrintStats();
   }
 
  private:
   // Read-only data.
   char pad0_[kCacheLineSize];
   atomic_uintptr_t max_size_;
   atomic_uintptr_t min_size_;
-  uptr max_cache_size_;
+  atomic_uintptr_t max_cache_size_;
   char pad1_[kCacheLineSize];
   SpinMutex cache_mutex_;
   SpinMutex recycle_mutex_;
   Cache cache_;
   char pad2_[kCacheLineSize];
 
   void NOINLINE Recycle(Callback cb) {
     Cache tmp;
-    uptr min_size = atomic_load(&min_size_, memory_order_acquire);
+    uptr min_size = atomic_load(&min_size_, memory_order_relaxed);
     {
       SpinMutexLock l(&cache_mutex_);
       while (cache_.Size() > min_size) {
         QuarantineBatch *b = cache_.DequeueBatch();
         tmp.EnqueueBatch(b);
       }
     }
     recycle_mutex_.Unlock();
NOINLINE QuarantineBatch* AllocBatch(Callback cb) {
     QuarantineBatch *b = (QuarantineBatch *)cb.Allocate(sizeof(*b));
     CHECK(b);
     b->count = 0;
     b->size = 0;
     list_.push_back(b);
     return b;
   }
 };
+
 } // namespace __sanitizer
 
 #endif // SANITIZER_QUARANTINE_H

test/asan/TestCases/Linux/thread_local_quarantine_size_kb.cc

 // Test thread_local_quarantine_size_kb
 
 // RUN: %clangxx_asan  %s -o %t
 // RUN: %env_asan_opts=thread_local_quarantine_size_kb=256:verbosity=1 %run %t 2>&1 | \
 // RUN:   FileCheck %s --check-prefix=CHECK-VALUE
 // RUN: %env_asan_opts=thread_local_quarantine_size_kb=64:quarantine_size_mb=64 %run %t 2>&1 | \
 // RUN:   FileCheck %s --allow-empty --check-prefix=CHECK-SMALL-LOCAL-CACHE-SMALL-OVERHEAD
-// RUN: %env_asan_opts=thread_local_quarantine_size_kb=0:quarantine_size_mb=64 %run %t 2>&1 | \
-// RUN:   FileCheck %s --check-prefix=CHECK-NO-LOCAL-CACHE-HUGE-OVERHEAD
+// RUN: %env_asan_opts=thread_local_quarantine_size_kb=0:quarantine_size_mb=0 %run %t 2>&1 | \
+// RUN:   FileCheck %s --check-prefix=CHECK-QUARANTINE-DISABLED
+// RUN: %env_asan_opts=thread_local_quarantine_size_kb=0:quarantine_size_mb=64 not %run %t 2>&1 | \
+// RUN:   FileCheck %s --check-prefix=CHECK-FOR-PARAMETER-ERROR
 
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sanitizer/allocator_interface.h>
 
 // The idea is allocate a lot of small blocks, totaling 5Mb of user memory
 // total, and verify that quarantine does not incur too much memory overhead.
int main() {
   fprintf(stderr, "heap size: new: %zd old: %zd\n", new_heap_size,
           old_heap_size);
   if (new_heap_size - old_heap_size > kHeapSizeLimit)
     fprintf(stderr, "Heap size limit exceeded");
 }
 
 // CHECK-VALUE: thread_local_quarantine_size_kb=256K
 // CHECK-SMALL-LOCAL-CACHE-SMALL-OVERHEAD-NOT: Heap size limit exceeded
-// CHECK-NO-LOCAL-CACHE-HUGE-OVERHEAD: Heap size limit exceeded
+// CHECK-QUARANTINE-DISABLED-NOT: Heap size limit exceeded
+// CHECK-FOR-PARAMETER-ERROR: thread_local_quarantine_size_kb can be set to 0 only when quarantine_size_mb is set to 0