diff --git a/unix/mkpost.go b/unix/mkpost.go
index 7938fe7b..c28e42b0 100644
--- a/unix/mkpost.go
+++ b/unix/mkpost.go
@@ -42,6 +42,10 @@ func main() {
 		log.Fatal(err)
 	}
 
+	// Intentionally export __val fields in Fsid and Sigset_t
+	valRegex := regexp.MustCompile(`type (Fsid|Sigset_t) struct {(\s+)X__val(\s+\S+\s+)}`)
+	b = valRegex.ReplaceAll(b, []byte("type $1 struct {${2}Val$3}"))
+
 	// If we have empty Ptrace structs, we should delete them. Only s390x emits
 	// nonempty Ptrace structs.
 	ptraceRexexp := regexp.MustCompile(`type Ptrace((Psw|Fpregs|Per) struct {\s*})`)
diff --git a/unix/ztypes_linux_386.go b/unix/ztypes_linux_386.go
index edb49049..b07e0482 100644
--- a/unix/ztypes_linux_386.go
+++ b/unix/ztypes_linux_386.go
@@ -171,7 +171,7 @@ type Dirent struct {
 }
 
 type Fsid struct {
-	_ [2]int32
+	Val [2]int32
 }
 
 type Flock_t struct {
@@ -739,7 +739,7 @@ const (
 )
 
 type Sigset_t struct {
-	_ [32]uint32
+	Val [32]uint32
 }
 
 const RNDGETENTCNT = 0x80045200
diff --git a/unix/ztypes_linux_amd64.go b/unix/ztypes_linux_amd64.go
index 560f7a94..d6f20821 100644
--- a/unix/ztypes_linux_amd64.go
+++ b/unix/ztypes_linux_amd64.go
@@ -171,7 +171,7 @@ type Dirent struct {
 }
 
 type Fsid struct {
-	_ [2]int32
+	Val [2]int32
 }
 
 type Flock_t struct {
@@ -757,7 +757,7 @@ const (
 )
 
 type Sigset_t struct {
-	_ [16]uint64
+	Val [16]uint64
 }
 
 const RNDGETENTCNT = 0x80045200
diff --git a/unix/ztypes_linux_arm.go b/unix/ztypes_linux_arm.go
index 6b87d03d..0920891f 100644
--- a/unix/ztypes_linux_arm.go
+++ b/unix/ztypes_linux_arm.go
@@ -173,7 +173,7 @@ type Dirent struct {
 }
 
 type Fsid struct {
-	_ [2]int32
+	Val [2]int32
 }
 
 type Flock_t struct {
@@ -728,7 +728,7 @@ const (
 )
 
 type Sigset_t struct {
-	_ [32]uint32
+	Val [32]uint32
 }
 
 const RNDGETENTCNT = 0x80045200
diff --git a/unix/ztypes_linux_arm64.go b/unix/ztypes_linux_arm64.go
index d147de24..d35d5ba7 100644
--- a/unix/ztypes_linux_arm64.go
+++ b/unix/ztypes_linux_arm64.go
@@ -172,7 +172,7 @@ type Dirent struct {
 }
 
 type Fsid struct {
-	_ [2]int32
+	Val [2]int32
 }
 
 type Flock_t struct {
@@ -736,7 +736,7 @@ const (
 )
 
 type Sigset_t struct {
-	_ [16]uint64
+	Val [16]uint64
 }
 
 const RNDGETENTCNT = 0x80045200
diff --git a/unix/ztypes_linux_mips.go b/unix/ztypes_linux_mips.go
index 0051dc4d..f1006741 100644
--- a/unix/ztypes_linux_mips.go
+++ b/unix/ztypes_linux_mips.go
@@ -172,7 +172,7 @@ type Dirent struct {
 }
 
 type Fsid struct {
-	_ [2]int32
+	Val [2]int32
 }
 
 type Flock_t struct {
@@ -733,7 +733,7 @@ const (
 )
 
 type Sigset_t struct {
-	_ [32]uint32
+	Val [32]uint32
 }
 
 const RNDGETENTCNT = 0x40045200
diff --git a/unix/ztypes_linux_mips64.go b/unix/ztypes_linux_mips64.go
index a67fbb42..1bc01bdd 100644
--- a/unix/ztypes_linux_mips64.go
+++ b/unix/ztypes_linux_mips64.go
@@ -172,7 +172,7 @@ type Dirent struct {
 }
 
 type Fsid struct {
-	_ [2]int32
+	Val [2]int32
 }
 
 type Flock_t struct {
@@ -738,7 +738,7 @@ const (
 )
 
 type Sigset_t struct {
-	_ [16]uint64
+	Val [16]uint64
 }
 
 const RNDGETENTCNT = 0x40045200
diff --git a/unix/ztypes_linux_mips64le.go b/unix/ztypes_linux_mips64le.go
index 41bd0978..af22a07b 100644
--- a/unix/ztypes_linux_mips64le.go
+++ b/unix/ztypes_linux_mips64le.go
@@ -172,7 +172,7 @@ type Dirent struct {
 }
 
 type Fsid struct {
-	_ [2]int32
+	Val [2]int32
 }
 
 type Flock_t struct {
@@ -738,7 +738,7 @@ const (
 )
 
 type Sigset_t struct {
-	_ [16]uint64
+	Val [16]uint64
 }
 
 const RNDGETENTCNT = 0x40045200
diff --git a/unix/ztypes_linux_mipsle.go b/unix/ztypes_linux_mipsle.go
index 46fa3f9b..67ac81ed 100644
--- a/unix/ztypes_linux_mipsle.go
+++ b/unix/ztypes_linux_mipsle.go
@@ -172,7 +172,7 @@ type Dirent struct {
 }
 
 type Fsid struct {
-	_ [2]int32
+	Val [2]int32
 }
 
 type Flock_t struct {
@@ -733,7 +733,7 @@ const (
 )
 
 type Sigset_t struct {
-	_ [32]uint32
+	Val [32]uint32
 }
 
 const RNDGETENTCNT = 0x40045200
diff --git a/unix/ztypes_linux_ppc64.go b/unix/ztypes_linux_ppc64.go
index e5758703..0c3b0561 100644
--- a/unix/ztypes_linux_ppc64.go
+++ b/unix/ztypes_linux_ppc64.go
@@ -173,7 +173,7 @@ type Dirent struct {
 }
 
 type Fsid struct {
-	_ [2]int32
+	Val [2]int32
 }
 
 type Flock_t struct {
@@ -746,7 +746,7 @@ const (
 )
 
 type Sigset_t struct {
-	_ [16]uint64
+	Val [16]uint64
 }
 
 const RNDGETENTCNT = 0x40045200
diff --git a/unix/ztypes_linux_ppc64le.go b/unix/ztypes_linux_ppc64le.go
index b2a92611..03a721e0 100644
--- a/unix/ztypes_linux_ppc64le.go
+++ b/unix/ztypes_linux_ppc64le.go
@@ -173,7 +173,7 @@ type Dirent struct {
 }
 
 type Fsid struct {
-	_ [2]int32
+	Val [2]int32
 }
 
 type Flock_t struct {
@@ -746,7 +746,7 @@ const (
 )
 
 type Sigset_t struct {
-	_ [16]uint64
+	Val [16]uint64
 }
 
 const RNDGETENTCNT = 0x40045200
diff --git a/unix/ztypes_linux_s390x.go b/unix/ztypes_linux_s390x.go
index c56ac409..a0217ff5 100644
--- a/unix/ztypes_linux_s390x.go
+++ b/unix/ztypes_linux_s390x.go
@@ -172,7 +172,7 @@ type Dirent struct {
 }
 
 type Fsid struct {
-	_ [2]int32
+	Val [2]int32
 }
 
 type Flock_t struct {
@@ -763,7 +763,7 @@ const (
 )
 
 type Sigset_t struct {
-	_ [16]uint64
+	Val [16]uint64
 }
 
 const RNDGETENTCNT = 0x80045200