diff --git a/lib/std/Io.zig b/lib/std/Io.zig
index bb9610c090..ea182c6803 100644
--- a/lib/std/Io.zig
+++ b/lib/std/Io.zig
@@ -1467,7 +1467,7 @@ pub const Event = enum(u32) {
     pub fn waitTimeout(event: *Event, io: Io, timeout: Timeout) WaitTimeoutError!void {
         if (@cmpxchgStrong(Event, event, .unset, .waiting, .acquire, .acquire)) |prev| switch (prev) {
             .unset => unreachable,
-            .waiting => assert(!builtin.single_threaded), // invalid state
+            .waiting => {},
             .is_set => return,
         };
         errdefer {
diff --git a/lib/std/Io/Threaded.zig b/lib/std/Io/Threaded.zig
index 46ff3a7f38..ca71271287 100644
--- a/lib/std/Io/Threaded.zig
+++ b/lib/std/Io/Threaded.zig
@@ -2461,7 +2461,10 @@ fn cancel(
 }
 
 fn futexWait(userdata: ?*anyopaque, ptr: *const u32, expected: u32, timeout: Io.Timeout) Io.Cancelable!void {
-    if (builtin.single_threaded) unreachable; // Deadlock.
+    if (builtin.single_threaded) {
+        assert(timeout != .none); // Deadlock.
+        return;
+    }
     const t: *Threaded = @ptrCast(@alignCast(userdata));
     const t_io = ioBasic(t);
     const timeout_ns: ?u64 = ns: {
@@ -2479,7 +2482,7 @@ fn futexWaitUncancelable(userdata: ?*anyopaque, ptr: *const u32, expected: u32)
 }
 
 fn futexWake(userdata: ?*anyopaque, ptr: *const u32, max_waiters: u32) void {
-    if (builtin.single_threaded) unreachable; // Nothing to wake up.
+    if (builtin.single_threaded) return; // Nothing to wake up.
     const t: *Threaded = @ptrCast(@alignCast(userdata));
     _ = t;
     Thread.futexWake(ptr, max_waiters);