diff --git a/src/cmd/internal/obj/link.go b/src/cmd/internal/obj/link.go
index dac6e209f1..3ebaa2aa5c 100644
--- a/src/cmd/internal/obj/link.go
+++ b/src/cmd/internal/obj/link.go
@@ -1058,6 +1058,10 @@ type Link struct {
 	// to Data.
 	constSyms []*LSym
 
+	// Windows SEH symbols are also data symbols that can be created
+	// concurrently.
+	SEHSyms []*LSym
+
 	// pkgIdx maps package path to index. The index is used for
 	// symbol reference in the object file.
 	pkgIdx map[string]int32
diff --git a/src/cmd/internal/obj/objfile.go b/src/cmd/internal/obj/objfile.go
index 3da8c30640..648aae4fa2 100644
--- a/src/cmd/internal/obj/objfile.go
+++ b/src/cmd/internal/obj/objfile.go
@@ -788,14 +788,18 @@ func genFuncInfoSyms(ctxt *Link) {
 		fn.FuncInfoSym = isym
 		b.Reset()
 
-		auxsyms := []*LSym{fn.dwarfRangesSym, fn.dwarfLocSym, fn.dwarfDebugLinesSym, fn.dwarfInfoSym, fn.WasmImportSym, fn.sehUnwindInfoSym}
+		auxsyms := []*LSym{fn.dwarfRangesSym, fn.dwarfLocSym, fn.dwarfDebugLinesSym, fn.dwarfInfoSym, fn.WasmImportSym}
 		for _, s := range auxsyms {
 			if s == nil || s.Size == 0 {
 				continue
 			}
+			if s.OnList() {
+				panic("a symbol is added to defs multiple times")
+			}
 			s.PkgIdx = goobj.PkgIdxSelf
 			s.SymIdx = symidx
 			s.Set(AttrIndexed, true)
+			s.Set(AttrOnList, true)
 			symidx++
 			infosyms = append(infosyms, s)
 		}
diff --git a/src/cmd/internal/obj/sym.go b/src/cmd/internal/obj/sym.go
index f27d4ef4fc..22153050f2 100644
--- a/src/cmd/internal/obj/sym.go
+++ b/src/cmd/internal/obj/sym.go
@@ -245,6 +245,13 @@ func (ctxt *Link) NumberSyms() {
 	ctxt.Data = append(ctxt.Data, ctxt.constSyms...)
 	ctxt.constSyms = nil
 
+	// So are SEH symbols.
+	sort.Slice(ctxt.SEHSyms, func(i, j int) bool {
+		return ctxt.SEHSyms[i].Name < ctxt.SEHSyms[j].Name
+	})
+	ctxt.Data = append(ctxt.Data, ctxt.SEHSyms...)
+	ctxt.SEHSyms = nil
+
 	ctxt.pkgIdx = make(map[string]int32)
 	ctxt.defs = []*LSym{}
 	ctxt.hashed64defs = []*LSym{}
diff --git a/src/cmd/internal/obj/x86/seh.go b/src/cmd/internal/obj/x86/seh.go
index 71cdd36642..11963e53f9 100644
--- a/src/cmd/internal/obj/x86/seh.go
+++ b/src/cmd/internal/obj/x86/seh.go
@@ -151,6 +151,7 @@ func populateSeh(ctxt *obj.Link, s *obj.LSym) (sehsym *obj.LSym) {
 		s.Type = objabi.SSEHUNWINDINFO
 		s.Set(obj.AttrDuplicateOK, true)
 		s.Set(obj.AttrLocal, true)
+		s.Set(obj.AttrContentAddressable, true)
 		if exceptionHandler != nil {
 			r := obj.Addrel(s)
 			r.Off = int32(len(buf.data) - 4)
@@ -158,8 +159,6 @@ func populateSeh(ctxt *obj.Link, s *obj.LSym) (sehsym *obj.LSym) {
 			r.Sym = exceptionHandler
 			r.Type = objabi.R_PEIMAGEOFF
 		}
-		// Note: AttrContentAddressable cannot be set here,
-		// because the content-addressable-handling code
-		// does not know about aux symbols.
+		ctxt.SEHSyms = append(ctxt.SEHSyms, s)
 	})
 }