diff --git a/src/pkg/runtime/linux/mem.c b/src/pkg/runtime/linux/mem.c
index 38ca7e4a0f9..ad0fac6d3f4 100644
--- a/src/pkg/runtime/linux/mem.c
+++ b/src/pkg/runtime/linux/mem.c
@@ -91,6 +91,9 @@ runtime·SysMap(void *v, uintptr n)
 		if(p != v && addrspace_free(v, n)) {
 			// On some systems, mmap ignores v without
 			// MAP_FIXED, so retry if the address space is free.
+			if(p > (void*)4096) {
+				runtime·munmap(p, n);
+			}
 			p = runtime·mmap(v, n, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_ANON|MAP_FIXED|MAP_PRIVATE, -1, 0);
 		}
 		if(p == (void*)ENOMEM)