Index: deps/v8/src/wasm/wasm-objects.cc
--- deps/v8/src/wasm/wasm-objects.cc.orig
+++ deps/v8/src/wasm/wasm-objects.cc
@@ -2855,7 +2855,15 @@ DirectHandle<WasmContinuationObject> WasmContinuationO
     wasm::JumpBuffer::StackState state, DirectHandle<HeapObject> parent,
     AllocationType allocation_type) {
   stack->jmpbuf()->stack_limit = stack->jslimit();
+#if V8_OS_OPENBSD
+  // OpenBSD MAP_STACK mappings cannot be entered with rsp exactly equal to the
+  // high end of the mapping. The first push from that value traps with
+  // SEGV_ACCERR, even though push would write below rsp. Keep the initial stack
+  // pointer strictly inside the mapped stack.
+  stack->jmpbuf()->sp = stack->base() - kSystemPointerSize;
+#else
   stack->jmpbuf()->sp = stack->base();
+#endif
   stack->jmpbuf()->fp = kNullAddress;
   stack->jmpbuf()->state = state;
   DirectHandle<WasmContinuationObject> result =
