5 files changed, 35 insertions, 10 deletions
diff --git a/pkg/abi/linux/netlink.go b/pkg/abi/linux/netlink.go
index e8b6544b4..0ba086c76 100644
--- a/pkg/abi/linux/netlink.go
+++ b/pkg/abi/linux/netlink.go
@@ -122,3 +122,9 @@ const (
 	NETLINK_EXT_ACK          = 11
 	NETLINK_DUMP_STRICT_CHK  = 12
 )
+
+// NetlinkErrorMessage is struct nlmsgerr, from uapi/linux/netlink.h.
+type NetlinkErrorMessage struct {
+	Error  int32
+	Header NetlinkMessageHeader
+}
diff --git a/pkg/sentry/kernel/seqatomic_taskgoroutineschedinfo_unsafe.go b/pkg/sentry/kernel/seqatomic_taskgoroutineschedinfo_unsafe.go
index c284a1b11..24528b66a 100755
--- a/pkg/sentry/kernel/seqatomic_taskgoroutineschedinfo_unsafe.go
+++ b/pkg/sentry/kernel/seqatomic_taskgoroutineschedinfo_unsafe.go
@@ -1,12 +1,12 @@
 package kernel
 
 import (
-	"reflect"
 	"strings"
 	"unsafe"
 
 	"fmt"
 	"gvisor.dev/gvisor/third_party/gvsync"
+	"reflect"
 )
 
 // SeqAtomicLoad returns a copy of *ptr, ensuring that the read does not race
diff --git a/pkg/sentry/platform/ring0/defs_impl.go b/pkg/sentry/platform/ring0/defs_impl.go
index d4bfc5a4a..8efc3825f 100755
--- a/pkg/sentry/platform/ring0/defs_impl.go
+++ b/pkg/sentry/platform/ring0/defs_impl.go
@@ -1,14 +1,14 @@
 package ring0
 
 import (
-	"syscall"
-
 	"fmt"
 	"gvisor.dev/gvisor/pkg/cpuid"
 	"gvisor.dev/gvisor/pkg/sentry/platform/ring0/pagetables"
-	"gvisor.dev/gvisor/pkg/sentry/usermem"
 	"io"
 	"reflect"
+	"syscall"
+
+	"gvisor.dev/gvisor/pkg/sentry/usermem"
 )
 
 var (
diff --git a/pkg/sentry/socket/netlink/socket.go b/pkg/sentry/socket/netlink/socket.go
index eccbd527a..d0aab293d 100644
--- a/pkg/sentry/socket/netlink/socket.go
+++ b/pkg/sentry/socket/netlink/socket.go
@@ -511,6 +511,19 @@ func (s *Socket) sendResponse(ctx context.Context, ms *MessageSet) *syserr.Error
 	return nil
 }
 
+func (s *Socket) dumpErrorMesage(ctx context.Context, hdr linux.NetlinkMessageHeader, ms *MessageSet, err *syserr.Error) *syserr.Error {
+	m := ms.AddMessage(linux.NetlinkMessageHeader{
+		Type: linux.NLMSG_ERROR,
+	})
+
+	m.Put(linux.NetlinkErrorMessage{
+		Error:  int32(-err.ToLinux().Number()),
+		Header: hdr,
+	})
+	return nil
+
+}
+
 // processMessages handles each message in buf, passing it to the protocol
 // handler for final handling.
 func (s *Socket) processMessages(ctx context.Context, buf []byte) *syserr.Error {
@@ -545,14 +558,20 @@ func (s *Socket) processMessages(ctx context.Context, buf []byte) *syserr.Error
 			continue
 		}
 
+		ms := NewMessageSet(s.portID, hdr.Seq)
+		var err *syserr.Error
 		// TODO(b/68877377): ACKs not supported yet.
 		if hdr.Flags&linux.NLM_F_ACK == linux.NLM_F_ACK {
-			return syserr.ErrNotSupported
-		}
+			err = syserr.ErrNotSupported
+		} else {
 
-		ms := NewMessageSet(s.portID, hdr.Seq)
-		if err := s.protocol.ProcessMessage(ctx, hdr, data, ms); err != nil {
-			return err
+			err = s.protocol.ProcessMessage(ctx, hdr, data, ms)
+		}
+		if err != nil {
+			ms = NewMessageSet(s.portID, hdr.Seq)
+			if err := s.dumpErrorMesage(ctx, hdr, ms, err); err != nil {
+				return err
+			}
 		}
 
 		if err := s.sendResponse(ctx, ms); err != nil {
diff --git a/pkg/sentry/time/seqatomic_parameters_unsafe.go b/pkg/sentry/time/seqatomic_parameters_unsafe.go
index 1ec221edd..fb30a22c6 100755
--- a/pkg/sentry/time/seqatomic_parameters_unsafe.go
+++ b/pkg/sentry/time/seqatomic_parameters_unsafe.go
@@ -1,12 +1,12 @@
 package time
 
 import (
-	"reflect"
 	"strings"
 	"unsafe"
 
 	"fmt"
 	"gvisor.dev/gvisor/third_party/gvsync"
+	"reflect"
 )
 
 // SeqAtomicLoad returns a copy of *ptr, ensuring that the read does not race