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internal/poll: don't use stack-allocated WSAMsg parameters
WSAMsg parameters should be passed to Windows as heap pointers instead of stack pointers. This is because Windows might access the memory after the syscall returned in case of a non-blocking operation (which is the common case), and if the WSAMsg is on the stack, the Go runtime might have moved it around. Use a sync.Pool to cache WSAMsg structures to avoid a heap allocation every time a WSAMsg is needed. Fixes #74933 Cq-Include-Trybots: luci.golang.try:x_net-gotip-windows-amd64 Change-Id: I075e2ceb25cd545224ab3a10d404340faf19fc01 Reviewed-on: https://go-review.googlesource.com/c/go/+/698797 Reviewed-by: Damien Neil <dneil@google.com> Reviewed-by: Cherry Mui <cherryyz@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
This commit is contained in:
qmuntal
Quim Muntal
parent
dae9e456ae
commit
bfd130db02
1 changed files with 69 additions and 44 deletions
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@ -144,19 +144,47 @@ func (o *operation) ClearBufs() {
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o.bufs = o.bufs[:0]
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}
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func newWSAMsg(p []byte, oob []byte, flags int) windows.WSAMsg {
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return windows.WSAMsg{
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Buffers: &syscall.WSABuf{
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Len: uint32(len(p)),
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Buf: unsafe.SliceData(p),
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},
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BufferCount: 1,
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Control: syscall.WSABuf{
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Len: uint32(len(oob)),
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Buf: unsafe.SliceData(oob),
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},
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Flags: uint32(flags),
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// wsaMsgPool is a pool of WSAMsg structures that can only hold a single WSABuf.
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var wsaMsgPool = sync.Pool{
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New: func() any {
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return &windows.WSAMsg{
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Buffers: &syscall.WSABuf{},
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BufferCount: 1,
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}
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},
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}
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// newWSAMsg creates a new WSAMsg with the provided parameters.
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// Use [freeWSAMsg] to free it.
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func newWSAMsg(p []byte, oob []byte, flags int, rsa *syscall.RawSockaddrAny) *windows.WSAMsg {
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// The returned object can't be allocated in the stack because it is accessed asynchronously
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// by Windows in between several system calls. If the stack frame is moved while that happens,
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// then Windows may access invalid memory.
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// TODO(qmuntal): investigate using runtime.Pinner keeping this path allocation-free.
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// Use a pool to reuse allocations.
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msg := wsaMsgPool.Get().(*windows.WSAMsg)
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msg.Buffers.Len = uint32(len(p))
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msg.Buffers.Buf = unsafe.SliceData(p)
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msg.Control = syscall.WSABuf{
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Len: uint32(len(oob)),
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Buf: unsafe.SliceData(oob),
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}
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msg.Flags = uint32(flags)
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msg.Name = syscall.Pointer(unsafe.Pointer(rsa))
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if rsa != nil {
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msg.Namelen = int32(unsafe.Sizeof(*rsa))
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} else {
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msg.Namelen = 0
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}
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return msg
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}
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func freeWSAMsg(msg *windows.WSAMsg) {
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// Clear pointers to buffers so they can be released by garbage collector.
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msg.Buffers.Len = 0
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msg.Buffers.Buf = nil
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wsaMsgPool.Put(msg)
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}
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// waitIO waits for the IO operation o to complete.
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@ -1297,11 +1325,10 @@ func (fd *FD) ReadMsg(p []byte, oob []byte, flags int) (int, int, int, syscall.S
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if o.rsa == nil {
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o.rsa = new(syscall.RawSockaddrAny)
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}
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msg := newWSAMsg(p, oob, flags)
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msg.Name = (syscall.Pointer)(unsafe.Pointer(o.rsa))
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msg.Namelen = int32(unsafe.Sizeof(*o.rsa))
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msg := newWSAMsg(p, oob, flags, o.rsa)
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defer freeWSAMsg(msg)
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n, err := fd.execIO(o, func(o *operation) (qty uint32, err error) {
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err = windows.WSARecvMsg(fd.Sysfd, &msg, &qty, &o.o, nil)
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err = windows.WSARecvMsg(fd.Sysfd, msg, &qty, &o.o, nil)
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return qty, err
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})
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err = fd.eofError(n, err)
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@ -1327,11 +1354,10 @@ func (fd *FD) ReadMsgInet4(p []byte, oob []byte, flags int, sa4 *syscall.Sockadd
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if o.rsa == nil {
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o.rsa = new(syscall.RawSockaddrAny)
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}
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msg := newWSAMsg(p, oob, flags)
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msg.Name = (syscall.Pointer)(unsafe.Pointer(o.rsa))
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msg.Namelen = int32(unsafe.Sizeof(*o.rsa))
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msg := newWSAMsg(p, oob, flags, o.rsa)
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defer freeWSAMsg(msg)
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n, err := fd.execIO(o, func(o *operation) (qty uint32, err error) {
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err = windows.WSARecvMsg(fd.Sysfd, &msg, &qty, &o.o, nil)
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err = windows.WSARecvMsg(fd.Sysfd, msg, &qty, &o.o, nil)
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return qty, err
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})
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err = fd.eofError(n, err)
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@ -1356,11 +1382,10 @@ func (fd *FD) ReadMsgInet6(p []byte, oob []byte, flags int, sa6 *syscall.Sockadd
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if o.rsa == nil {
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o.rsa = new(syscall.RawSockaddrAny)
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}
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msg := newWSAMsg(p, oob, flags)
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msg.Name = (syscall.Pointer)(unsafe.Pointer(o.rsa))
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msg.Namelen = int32(unsafe.Sizeof(*o.rsa))
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msg := newWSAMsg(p, oob, flags, o.rsa)
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defer freeWSAMsg(msg)
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n, err := fd.execIO(o, func(o *operation) (qty uint32, err error) {
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err = windows.WSARecvMsg(fd.Sysfd, &msg, &qty, &o.o, nil)
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err = windows.WSARecvMsg(fd.Sysfd, msg, &qty, &o.o, nil)
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return qty, err
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})
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err = fd.eofError(n, err)
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@ -1382,20 +1407,20 @@ func (fd *FD) WriteMsg(p []byte, oob []byte, sa syscall.Sockaddr) (int, int, err
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defer fd.writeUnlock()
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o := &fd.wop
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msg := newWSAMsg(p, oob, 0)
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if sa != nil && o.rsa == nil {
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o.rsa = new(syscall.RawSockaddrAny)
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}
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msg := newWSAMsg(p, oob, 0, o.rsa)
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defer freeWSAMsg(msg)
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if sa != nil {
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if o.rsa == nil {
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o.rsa = new(syscall.RawSockaddrAny)
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}
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len, err := sockaddrToRaw(o.rsa, sa)
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var err error
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msg.Namelen, err = sockaddrToRaw(o.rsa, sa)
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if err != nil {
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return 0, 0, err
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}
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msg.Name = (syscall.Pointer)(unsafe.Pointer(o.rsa))
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msg.Namelen = len
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}
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n, err := fd.execIO(o, func(o *operation) (qty uint32, err error) {
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err = windows.WSASendMsg(fd.Sysfd, &msg, 0, nil, &o.o, nil)
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err = windows.WSASendMsg(fd.Sysfd, msg, 0, nil, &o.o, nil)
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return qty, err
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})
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return n, int(msg.Control.Len), err
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@ -1413,16 +1438,16 @@ func (fd *FD) WriteMsgInet4(p []byte, oob []byte, sa *syscall.SockaddrInet4) (in
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defer fd.writeUnlock()
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o := &fd.wop
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msg := newWSAMsg(p, oob, 0)
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if sa != nil && o.rsa == nil {
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o.rsa = new(syscall.RawSockaddrAny)
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}
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msg := newWSAMsg(p, oob, 0, o.rsa)
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defer freeWSAMsg(msg)
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if sa != nil {
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if o.rsa == nil {
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o.rsa = new(syscall.RawSockaddrAny)
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}
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msg.Name = (syscall.Pointer)(unsafe.Pointer(o.rsa))
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msg.Namelen = sockaddrInet4ToRaw(o.rsa, sa)
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}
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n, err := fd.execIO(o, func(o *operation) (qty uint32, err error) {
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err = windows.WSASendMsg(fd.Sysfd, &msg, 0, nil, &o.o, nil)
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err = windows.WSASendMsg(fd.Sysfd, msg, 0, nil, &o.o, nil)
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return qty, err
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})
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return n, int(msg.Control.Len), err
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@ -1440,16 +1465,16 @@ func (fd *FD) WriteMsgInet6(p []byte, oob []byte, sa *syscall.SockaddrInet6) (in
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defer fd.writeUnlock()
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o := &fd.wop
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msg := newWSAMsg(p, oob, 0)
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if sa != nil && o.rsa == nil {
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o.rsa = new(syscall.RawSockaddrAny)
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}
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msg := newWSAMsg(p, oob, 0, o.rsa)
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defer freeWSAMsg(msg)
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if sa != nil {
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if o.rsa == nil {
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o.rsa = new(syscall.RawSockaddrAny)
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}
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msg.Name = (syscall.Pointer)(unsafe.Pointer(o.rsa))
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msg.Namelen = sockaddrInet6ToRaw(o.rsa, sa)
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}
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n, err := fd.execIO(o, func(o *operation) (qty uint32, err error) {
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err = windows.WSASendMsg(fd.Sysfd, &msg, 0, nil, &o.o, nil)
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err = windows.WSASendMsg(fd.Sysfd, msg, 0, nil, &o.o, nil)
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return qty, err
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})
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return n, int(msg.Control.Len), err
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