fix corruption due to data race when concurrently calling

cpp/src/arrow/filesystem/s3fs.cc

@@ -2898,7 +2898,8 @@ struct AwsInstance {
     if (is_finalized_.load()) {
       return Status::Invalid("Attempt to initialize S3 after it has been finalized");
     }
-    if (!is_initialized_.exchange(true)) {
+    bool expected = false;
+    if (!is_initialized_.compare_exchange_weak(expected, true)) {
       // Not already initialized
       DoInitialize(options);
       return true;

cpp/src/arrow/filesystem/s3fs_test.cc

@@ -1272,6 +1272,30 @@ TEST_F(TestS3FS, FileSystemFromUri) {
   AssertFileInfo(fs.get(), path, FileType::File, 8);
 }
 
+TEST_F(TestS3FS, ConcurrentFSInit) {
+  auto test_thread = [this]() {
+    std::stringstream ss;
+    ss << "s3://" << minio_->access_key() << ":" << minio_->secret_key()
+       << "@bucket/somedir/subdir/subfile"
+       << "?scheme=http&endpoint_override=" << UriEscape(minio_->connect_string());
+
+    std::string path;
+    ASSERT_OK(FileSystemFromUri(ss.str(), &path));
+  };
+
+  const int num_threads = 4;
+  auto threads = std::vector<std::thread>();
+  for (int i = 0; i < num_threads; i++) {
+    threads.emplace_back(test_thread);
+  }
+
+  for (auto& thread : threads) {
+    thread.join();
+  }
+
+  static_cast<void>(FinalizeS3());
+}
+
 TEST_F(TestS3FS, NoCreateDeleteBucket) {
   // Create a bucket to try deleting
   ASSERT_OK(fs_->CreateDir("test-no-delete"));