diff --git a/adb/fdevent.cpp b/adb/fdevent.cpp
index ba82e7c5f..f3b8ef5ca 100644
--- a/adb/fdevent.cpp
+++ b/adb/fdevent.cpp
@@ -402,6 +402,10 @@ static void fdevent_run_setup() {
             PLOG(FATAL) << "failed to create run queue notify socketpair";
         }
 
+        if (!set_file_block_mode(s[0], false) || !set_file_block_mode(s[1], false)) {
+            PLOG(FATAL) << "failed to make run queue notify socket nonblocking";
+        }
+
         run_queue_notify_fd.reset(s[0]);
         fdevent* fde = fdevent_create(s[1], fdevent_run_func, nullptr);
         CHECK(fde != nullptr);
@@ -418,7 +422,12 @@ void fdevent_run_on_main_thread(std::function<void()> fn) {
     // run_queue_notify_fd could still be -1 if we're called before fdevent has finished setting up.
     // In that case, rely on the setup code to flush the queue without a notification being needed.
     if (run_queue_notify_fd != -1) {
-        if (adb_write(run_queue_notify_fd.get(), "", 1) != 1) {
+        int rc = adb_write(run_queue_notify_fd.get(), "", 1);
+
+        // It's possible that we get EAGAIN here, if lots of notifications came in while handling.
+        if (rc == 0) {
+            PLOG(FATAL) << "run queue notify fd was closed?";
+        } else if (rc == -1 && errno != EAGAIN) {
             PLOG(FATAL) << "failed to write to run queue notify fd";
         }
     }
diff --git a/adb/fdevent_test.cpp b/adb/fdevent_test.cpp
index dadae5ab7..95dc4c248 100644
--- a/adb/fdevent_test.cpp
+++ b/adb/fdevent_test.cpp
@@ -180,7 +180,13 @@ TEST_F(FdeventTest, run_on_main_thread) {
     PrepareThread();
     std::thread thread(fdevent_loop);
 
-    for (int i = 0; i < 100; ++i) {
+    // Block the main thread for a long time while we queue our callbacks.
+    fdevent_run_on_main_thread([]() {
+        check_main_thread();
+        std::this_thread::sleep_for(std::chrono::seconds(1));
+    });
+
+    for (int i = 0; i < 1000000; ++i) {
         fdevent_run_on_main_thread([i, &vec]() {
             check_main_thread();
             vec.push_back(i);
@@ -189,8 +195,8 @@ TEST_F(FdeventTest, run_on_main_thread) {
 
     TerminateThread(thread);
 
-    ASSERT_EQ(100u, vec.size());
-    for (int i = 0; i < 100; ++i) {
+    ASSERT_EQ(1000000u, vec.size());
+    for (int i = 0; i < 1000000; ++i) {
         ASSERT_EQ(i, vec[i]);
     }
 }