Fix memleak in fsspool (#1115)

google · Jun 29, 2023 · 020827b · 020827b
1 parent baa31a5
commit 020827b
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Showing 2 changed files with 7 additions and 2 deletions.
diff --git a/Source/santad/Logs/EndpointSecurity/Writers/FSSpool/fsspool_log_batch_writer.cc b/Source/santad/Logs/EndpointSecurity/Writers/FSSpool/fsspool_log_batch_writer.cc
@@ -56,7 +56,12 @@ absl::Status FsSpoolLogBatchWriter::FlushNoLock() {
       return status;
     }
   }
-  cache_.mutable_records()->Clear();
+  // We assign a new LogBatch() object here instead of calling Clear() method to
+  // make sure the memory used by the cache_ is actually freed. It seems that
+  // internal implementation of protobuf has some very generous way of managing
+  // memory allocations and in certain scenarios it keeps objects for a very
+  // long time (forever?).
+  cache_ = santa::fsspool::binaryproto::LogBatch();
   cache_.mutable_records()->Reserve(max_batch_size_);
   return absl::OkStatus();
 }

diff --git a/Source/santad/Logs/EndpointSecurity/Writers/FSSpool/fsspool_log_batch_writer.h b/Source/santad/Logs/EndpointSecurity/Writers/FSSpool/fsspool_log_batch_writer.h
@@ -62,7 +62,7 @@ class FsSpoolLogBatchWriter {
   absl::Mutex cache_mutex_;
   santa::fsspool::binaryproto::LogBatch cache_ ABSL_GUARDED_BY(cache_mutex_);
 
-  absl::Status FlushNoLock() ABSL_SHARED_LOCKS_REQUIRED(cache_mutex_);
+  absl::Status FlushNoLock() ABSL_EXCLUSIVE_LOCKS_REQUIRED(cache_mutex_);
 };
 
 }  // namespace fsspool