// Copyright 2013 The Go Authors. All rights reserved. // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE file. package runtime_test import ( "os" "syscall" "testing" "unsafe" ) // TestMemmoveOverflow maps 3GB of memory and calls memmove on // the corresponding slice. func TestMemmoveOverflow(t *testing.T) { t.Parallel() // Create a temporary file. tmp, err := os.CreateTemp("", "go-memmovetest") if err != nil { t.Fatal(err) } _, err = tmp.Write(make([]byte, 65536)) if err != nil { t.Fatal(err) } defer os.Remove(tmp.Name()) defer tmp.Close() // Set up mappings. base, _, errno := syscall.Syscall6(syscall.SYS_MMAP, 0xa0<<32, 3<<30, syscall.PROT_READ|syscall.PROT_WRITE, syscall.MAP_PRIVATE|syscall.MAP_ANONYMOUS, ^uintptr(0), 0) if errno != 0 { t.Skipf("could not create memory mapping: %s", errno) } syscall.Syscall(syscall.SYS_MUNMAP, base, 3<<30, 0) for off := uintptr(0); off < 3<<30; off += 65536 { _, _, errno := syscall.Syscall6(syscall.SYS_MMAP, base+off, 65536, syscall.PROT_READ|syscall.PROT_WRITE, syscall.MAP_SHARED|syscall.MAP_FIXED, tmp.Fd(), 0) if errno != 0 { t.Skipf("could not map a page at requested 0x%x: %s", base+off, errno) } defer syscall.Syscall(syscall.SYS_MUNMAP, base+off, 65536, 0) } s := unsafe.Slice((*byte)(unsafe.Pointer(base)), 3<<30) n := copy(s[1:], s) if n != 3<<30-1 { t.Fatalf("copied %d bytes, expected %d", n, 3<<30-1) } n = copy(s, s[1:]) if n != 3<<30-1 { t.Fatalf("copied %d bytes, expected %d", n, 3<<30-1) } }