diff --git a/adb/socket_test.cpp b/adb/socket_test.cpp
index 6b40056..f587fdb 100644
--- a/adb/socket_test.cpp
+++ b/adb/socket_test.cpp
@@ -42,7 +42,9 @@
 
 class LocalSocketTest : public FdeventTest {};
 
-constexpr auto SLEEP_FOR_FDEVENT = 100ms;
+static void WaitForFdeventLoop() {
+    std::this_thread::sleep_for(100ms);
+}
 
 TEST_F(LocalSocketTest, smoke) {
     // Join two socketpairs with a chain of intermediate socketpairs.
@@ -98,7 +100,7 @@
     ASSERT_EQ(0, adb_close(last[1]));
 
     // Wait until the local sockets are closed.
-    std::this_thread::sleep_for(SLEEP_FOR_FDEVENT);
+    WaitForFdeventLoop();
     ASSERT_EQ(GetAdditionalLocalSocketCount(), fdevent_installed_count());
     TerminateThread(thread);
 }
@@ -144,13 +146,15 @@
 
     PrepareThread();
     std::thread thread(CloseWithPacketThreadFunc, &arg);
-    // Wait until the fdevent_loop() starts.
-    std::this_thread::sleep_for(SLEEP_FOR_FDEVENT);
+
+    WaitForFdeventLoop();
     ASSERT_EQ(0, adb_close(cause_close_fd[0]));
-    std::this_thread::sleep_for(SLEEP_FOR_FDEVENT);
+
+    WaitForFdeventLoop();
     EXPECT_EQ(1u + GetAdditionalLocalSocketCount(), fdevent_installed_count());
     ASSERT_EQ(0, adb_close(socket_fd[0]));
-    std::this_thread::sleep_for(SLEEP_FOR_FDEVENT);
+
+    WaitForFdeventLoop();
     ASSERT_EQ(GetAdditionalLocalSocketCount(), fdevent_installed_count());
     TerminateThread(thread);
 }
@@ -167,10 +171,11 @@
 
     PrepareThread();
     std::thread thread(CloseWithPacketThreadFunc, &arg);
-    // Wait until the fdevent_loop() starts.
-    std::this_thread::sleep_for(SLEEP_FOR_FDEVENT);
+
+    WaitForFdeventLoop();
     ASSERT_EQ(0, adb_close(cause_close_fd[0]));
-    std::this_thread::sleep_for(SLEEP_FOR_FDEVENT);
+
+    WaitForFdeventLoop();
     EXPECT_EQ(1u + GetAdditionalLocalSocketCount(), fdevent_installed_count());
 
     // Verify if we can read successfully.
@@ -179,7 +184,7 @@
     ASSERT_EQ(true, ReadFdExactly(socket_fd[0], buf.data(), buf.size()));
     ASSERT_EQ(0, adb_close(socket_fd[0]));
 
-    std::this_thread::sleep_for(SLEEP_FOR_FDEVENT);
+    WaitForFdeventLoop();
     ASSERT_EQ(GetAdditionalLocalSocketCount(), fdevent_installed_count());
     TerminateThread(thread);
 }
@@ -199,12 +204,12 @@
 
     PrepareThread();
     std::thread thread(CloseWithPacketThreadFunc, &arg);
-    // Wait until the fdevent_loop() starts.
-    std::this_thread::sleep_for(SLEEP_FOR_FDEVENT);
+
+    WaitForFdeventLoop();
     EXPECT_EQ(2u + GetAdditionalLocalSocketCount(), fdevent_installed_count());
     ASSERT_EQ(0, adb_close(socket_fd[0]));
 
-    std::this_thread::sleep_for(SLEEP_FOR_FDEVENT);
+    WaitForFdeventLoop();
     ASSERT_EQ(GetAdditionalLocalSocketCount(), fdevent_installed_count());
     TerminateThread(thread);
 }
@@ -242,8 +247,7 @@
     adb_close(head_fd[0]);
     adb_close(tail_fd[0]);
 
-    // Wait until the local sockets are closed.
-    std::this_thread::sleep_for(SLEEP_FOR_FDEVENT);
+    WaitForFdeventLoop();
     ASSERT_EQ(GetAdditionalLocalSocketCount(), fdevent_installed_count());
     TerminateThread(thread);
 }
@@ -285,14 +289,13 @@
     PrepareThread();
     std::thread thread(CloseRdHupSocketThreadFunc, &arg);
 
-    // Wait until the fdevent_loop() starts.
-    std::this_thread::sleep_for(SLEEP_FOR_FDEVENT);
+    WaitForFdeventLoop();
     EXPECT_EQ(1u + GetAdditionalLocalSocketCount(), fdevent_installed_count());
 
     // Wait until the client closes its socket.
     client_thread.join();
 
-    std::this_thread::sleep_for(SLEEP_FOR_FDEVENT);
+    WaitForFdeventLoop();
     ASSERT_EQ(GetAdditionalLocalSocketCount(), fdevent_installed_count());
     TerminateThread(thread);
 }
diff --git a/adb/sysdeps_test.cpp b/adb/sysdeps_test.cpp
index fd19882..79cebe6 100644
--- a/adb/sysdeps_test.cpp
+++ b/adb/sysdeps_test.cpp
@@ -121,10 +121,13 @@
     adb_pollfd pfd[3] = {};
     pfd[0].fd = fds[0];
     pfd[0].events = POLLRDNORM;
+    pfd[0].revents = ~0;
     pfd[1].fd = INT_MAX;
     pfd[1].events = POLLRDNORM;
+    pfd[1].revents = ~0;
     pfd[2].fd = fds[1];
     pfd[2].events = POLLWRNORM;
+    pfd[2].revents = ~0;
 
     ASSERT_TRUE(WriteFdExactly(fds[1], "foo", 4));
 
@@ -136,6 +139,17 @@
     EXPECT_EQ(POLLRDNORM, pfd[0].revents);
     EXPECT_EQ(POLLNVAL, pfd[1].revents);
     EXPECT_EQ(POLLWRNORM, pfd[2].revents);
+
+    // Make sure that we return immediately if an invalid FD is given.
+    pfd[0].fd = fds[0];
+    pfd[0].events = POLLRDNORM;
+    pfd[0].revents = ~0;
+    pfd[1].fd = INT_MAX;
+    pfd[1].events = POLLRDNORM;
+    pfd[1].revents = ~0;
+    EXPECT_EQ(2, adb_poll(pfd, 2, -1));
+    EXPECT_EQ(POLLRDNORM, pfd[0].revents);
+    EXPECT_EQ(POLLNVAL, pfd[1].revents);
 }
 
 TEST_F(sysdeps_poll, duplicate_fd) {
diff --git a/adb/sysdeps_win32.cpp b/adb/sysdeps_win32.cpp
index 62f4ac8..7d35fb6 100644
--- a/adb/sysdeps_win32.cpp
+++ b/adb/sysdeps_win32.cpp
@@ -529,6 +529,7 @@
     int skipped = 0;
     std::vector<WSAPOLLFD> sockets;
     std::vector<adb_pollfd*> original;
+
     for (size_t i = 0; i < nfds; ++i) {
         FH fh = _fh_from_int(fds[i].fd, __func__);
         if (!fh || !fh->used || fh->clazz != &_fh_socket_class) {
@@ -549,6 +550,11 @@
         return skipped;
     }
 
+    // If we have any invalid FDs in our FD set, make sure to return immediately.
+    if (skipped > 0) {
+        timeout = 0;
+    }
+
     int result = WSAPoll(sockets.data(), sockets.size(), timeout);
     if (result == SOCKET_ERROR) {
         _socket_set_errno(WSAGetLastError());
@@ -560,7 +566,7 @@
         original[i]->revents = sockets[i].revents;
     }
 
-    // WSAPoll appears to return the number of unique FDs with avaiable events, instead of how many
+    // WSAPoll appears to return the number of unique FDs with available events, instead of how many
     // of the pollfd elements have a non-zero revents field, which is what it and poll are specified
     // to do. Ignore its result and calculate the proper return value.
     result = 0;