diff --git a/unix/syscall_linux.go b/unix/syscall_linux.go
index a8ae8a57..6a2c5cda 100644
--- a/unix/syscall_linux.go
+++ b/unix/syscall_linux.go
@@ -13,7 +13,6 @@ package unix
 
 import (
 	"encoding/binary"
-	"runtime"
 	"syscall"
 	"unsafe"
 )
@@ -1820,11 +1819,7 @@ func Sendfile(outfd int, infd int, offset *int64, count int) (written int, err e
 //sys	Dup(oldfd int) (fd int, err error)
 
 func Dup2(oldfd, newfd int) error {
-	// Android O and newer blocks dup2; riscv and arm64 don't implement dup2.
-	if runtime.GOOS == "android" || runtime.GOARCH == "riscv64" || runtime.GOARCH == "arm64" {
-		return Dup3(oldfd, newfd, 0)
-	}
-	return dup2(oldfd, newfd)
+	return Dup3(oldfd, newfd, 0)
 }
 
 //sys	Dup3(oldfd int, newfd int, flags int) (err error)
diff --git a/unix/syscall_linux_386.go b/unix/syscall_linux_386.go
index 9ce92216..08b3f6a1 100644
--- a/unix/syscall_linux_386.go
+++ b/unix/syscall_linux_386.go
@@ -21,7 +21,6 @@ func setTimeval(sec, usec int64) Timeval {
 
 // 64-bit file system and 32-bit uid calls
 // (386 default is 32-bit file system and 16-bit uid).
-//sys	dup2(oldfd int, newfd int) (err error)
 //sys	EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error)
 //sys	Fadvise(fd int, offset int64, length int64, advice int) (err error) = SYS_FADVISE64_64
 //sys	Fchown(fd int, uid int, gid int) (err error) = SYS_FCHOWN32
diff --git a/unix/syscall_linux_amd64.go b/unix/syscall_linux_amd64.go
index f18b63a8..dc31a15a 100644
--- a/unix/syscall_linux_amd64.go
+++ b/unix/syscall_linux_amd64.go
@@ -7,7 +7,6 @@
 
 package unix
 
-//sys	dup2(oldfd int, newfd int) (err error)
 //sys	EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error)
 //sys	Fadvise(fd int, offset int64, length int64, advice int) (err error) = SYS_FADVISE64
 //sys	Fchown(fd int, uid int, gid int) (err error)
diff --git a/unix/syscall_linux_arm.go b/unix/syscall_linux_arm.go
index 7d1dbd3d..1d136bae 100644
--- a/unix/syscall_linux_arm.go
+++ b/unix/syscall_linux_arm.go
@@ -46,7 +46,6 @@ func Seek(fd int, offset int64, whence int) (newoffset int64, err error) {
 
 // 64-bit file system and 32-bit uid calls
 // (16-bit uid calls are not always supported in newer kernels)
-//sys	dup2(oldfd int, newfd int) (err error)
 //sys	EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error)
 //sys	Fchown(fd int, uid int, gid int) (err error) = SYS_FCHOWN32
 //sys	Fstat(fd int, stat *Stat_t) (err error) = SYS_FSTAT64
diff --git a/unix/syscall_linux_arm64.go b/unix/syscall_linux_arm64.go
index 75b40a9b..9c715dc4 100644
--- a/unix/syscall_linux_arm64.go
+++ b/unix/syscall_linux_arm64.go
@@ -180,10 +180,6 @@ func (rsa *RawSockaddrNFCLLCP) SetServiceNameLen(length int) {
 	rsa.Service_name_len = uint64(length)
 }
 
-// dup2 exists because func Dup3 in syscall_linux.go references
-// it in an unreachable path. dup2 isn't available on arm64.
-func dup2(oldfd int, newfd int) error
-
 func Pause() error {
 	_, err := ppoll(nil, 0, nil, nil)
 	return err
diff --git a/unix/syscall_linux_mips64x.go b/unix/syscall_linux_mips64x.go
index 36b27529..d47ceafa 100644
--- a/unix/syscall_linux_mips64x.go
+++ b/unix/syscall_linux_mips64x.go
@@ -8,7 +8,6 @@
 
 package unix
 
-//sys	dup2(oldfd int, newfd int) (err error)
 //sys	EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error)
 //sys	Fadvise(fd int, offset int64, length int64, advice int) (err error) = SYS_FADVISE64
 //sys	Fchown(fd int, uid int, gid int) (err error)
diff --git a/unix/syscall_linux_mipsx.go b/unix/syscall_linux_mipsx.go
index d0b8b232..27ee4db6 100644
--- a/unix/syscall_linux_mipsx.go
+++ b/unix/syscall_linux_mipsx.go
@@ -15,7 +15,6 @@ import (
 
 func Syscall9(trap, a1, a2, a3, a4, a5, a6, a7, a8, a9 uintptr) (r1, r2 uintptr, err syscall.Errno)
 
-//sys	dup2(oldfd int, newfd int) (err error)
 //sys	EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error)
 //sys	Fadvise(fd int, offset int64, length int64, advice int) (err error) = SYS_FADVISE64
 //sys	Fchown(fd int, uid int, gid int) (err error)
diff --git a/unix/syscall_linux_ppc.go b/unix/syscall_linux_ppc.go
index c28fa34d..299ba9de 100644
--- a/unix/syscall_linux_ppc.go
+++ b/unix/syscall_linux_ppc.go
@@ -12,7 +12,6 @@ import (
 	"unsafe"
 )
 
-//sys	dup2(oldfd int, newfd int) (err error)
 //sys	EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error)
 //sys	Fchown(fd int, uid int, gid int) (err error)
 //sys	Fstat(fd int, stat *Stat_t) (err error) = SYS_FSTAT64
diff --git a/unix/syscall_linux_ppc64x.go b/unix/syscall_linux_ppc64x.go
index 2ba4aa76..0873b07b 100644
--- a/unix/syscall_linux_ppc64x.go
+++ b/unix/syscall_linux_ppc64x.go
@@ -8,7 +8,6 @@
 
 package unix
 
-//sys	dup2(oldfd int, newfd int) (err error)
 //sys	EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error)
 //sys	Fadvise(fd int, offset int64, length int64, advice int) (err error) = SYS_FADVISE64
 //sys	Fchown(fd int, uid int, gid int) (err error)
diff --git a/unix/syscall_linux_riscv64.go b/unix/syscall_linux_riscv64.go
index 97468c59..e2c5b32f 100644
--- a/unix/syscall_linux_riscv64.go
+++ b/unix/syscall_linux_riscv64.go
@@ -194,7 +194,3 @@ func KexecFileLoad(kernelFd int, initrdFd int, cmdline string, flags int) error
 	}
 	return kexecFileLoad(kernelFd, initrdFd, cmdlineLen, cmdline, flags)
 }
-
-// dup2 exists because func Dup3 in syscall_linux.go references
-// it in an unreachable path. dup2 isn't available on arm64.
-func dup2(oldfd int, newfd int) error
diff --git a/unix/syscall_linux_s390x.go b/unix/syscall_linux_s390x.go
index 3236feec..dfa204db 100644
--- a/unix/syscall_linux_s390x.go
+++ b/unix/syscall_linux_s390x.go
@@ -11,7 +11,6 @@ import (
 	"unsafe"
 )
 
-//sys	dup2(oldfd int, newfd int) (err error)
 //sys	EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error)
 //sys	Fadvise(fd int, offset int64, length int64, advice int) (err error) = SYS_FADVISE64
 //sys	Fchown(fd int, uid int, gid int) (err error)
diff --git a/unix/syscall_linux_sparc64.go b/unix/syscall_linux_sparc64.go
index 0544d967..4c54e093 100644
--- a/unix/syscall_linux_sparc64.go
+++ b/unix/syscall_linux_sparc64.go
@@ -9,7 +9,6 @@ package unix
 
 //sys	EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error)
 //sys	Fadvise(fd int, offset int64, length int64, advice int) (err error) = SYS_FADVISE64
-//sys	dup2(oldfd int, newfd int) (err error)
 //sys	Fchown(fd int, uid int, gid int) (err error)
 //sys	Fstat(fd int, stat *Stat_t) (err error)
 //sys	Fstatat(dirfd int, path string, stat *Stat_t, flags int) (err error) = SYS_FSTATAT64
diff --git a/unix/zsyscall_linux_386.go b/unix/zsyscall_linux_386.go
index f32cec99..7f3eccfc 100644
--- a/unix/zsyscall_linux_386.go
+++ b/unix/zsyscall_linux_386.go
@@ -46,16 +46,6 @@ func Tee(rfd int, wfd int, len int, flags int) (n int64, err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func dup2(oldfd int, newfd int) (err error) {
-	_, _, e1 := Syscall(SYS_DUP2, uintptr(oldfd), uintptr(newfd), 0)
-	if e1 != 0 {
-		err = errnoErr(e1)
-	}
-	return
-}
-
-// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
-
 func EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error) {
 	var _p0 unsafe.Pointer
 	if len(events) > 0 {
diff --git a/unix/zsyscall_linux_amd64.go b/unix/zsyscall_linux_amd64.go
index c9bf2fe2..c1c9ac4d 100644
--- a/unix/zsyscall_linux_amd64.go
+++ b/unix/zsyscall_linux_amd64.go
@@ -46,16 +46,6 @@ func Tee(rfd int, wfd int, len int, flags int) (n int64, err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func dup2(oldfd int, newfd int) (err error) {
-	_, _, e1 := Syscall(SYS_DUP2, uintptr(oldfd), uintptr(newfd), 0)
-	if e1 != 0 {
-		err = errnoErr(e1)
-	}
-	return
-}
-
-// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
-
 func EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error) {
 	var _p0 unsafe.Pointer
 	if len(events) > 0 {
diff --git a/unix/zsyscall_linux_arm.go b/unix/zsyscall_linux_arm.go
index 39cca714..d89b8be3 100644
--- a/unix/zsyscall_linux_arm.go
+++ b/unix/zsyscall_linux_arm.go
@@ -225,16 +225,6 @@ func sendmsg(s int, msg *Msghdr, flags int) (n int, err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func dup2(oldfd int, newfd int) (err error) {
-	_, _, e1 := Syscall(SYS_DUP2, uintptr(oldfd), uintptr(newfd), 0)
-	if e1 != 0 {
-		err = errnoErr(e1)
-	}
-	return
-}
-
-// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
-
 func EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error) {
 	var _p0 unsafe.Pointer
 	if len(events) > 0 {
diff --git a/unix/zsyscall_linux_mips.go b/unix/zsyscall_linux_mips.go
index 1bf98982..9e609dd9 100644
--- a/unix/zsyscall_linux_mips.go
+++ b/unix/zsyscall_linux_mips.go
@@ -46,16 +46,6 @@ func Tee(rfd int, wfd int, len int, flags int) (n int64, err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func dup2(oldfd int, newfd int) (err error) {
-	_, _, e1 := Syscall(SYS_DUP2, uintptr(oldfd), uintptr(newfd), 0)
-	if e1 != 0 {
-		err = errnoErr(e1)
-	}
-	return
-}
-
-// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
-
 func EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error) {
 	var _p0 unsafe.Pointer
 	if len(events) > 0 {
diff --git a/unix/zsyscall_linux_mips64.go b/unix/zsyscall_linux_mips64.go
index f7d253f8..46b1d82f 100644
--- a/unix/zsyscall_linux_mips64.go
+++ b/unix/zsyscall_linux_mips64.go
@@ -46,16 +46,6 @@ func Tee(rfd int, wfd int, len int, flags int) (n int64, err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func dup2(oldfd int, newfd int) (err error) {
-	_, _, e1 := Syscall(SYS_DUP2, uintptr(oldfd), uintptr(newfd), 0)
-	if e1 != 0 {
-		err = errnoErr(e1)
-	}
-	return
-}
-
-// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
-
 func EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error) {
 	var _p0 unsafe.Pointer
 	if len(events) > 0 {
diff --git a/unix/zsyscall_linux_mips64le.go b/unix/zsyscall_linux_mips64le.go
index f5799bf5..ab2f9db7 100644
--- a/unix/zsyscall_linux_mips64le.go
+++ b/unix/zsyscall_linux_mips64le.go
@@ -46,16 +46,6 @@ func Tee(rfd int, wfd int, len int, flags int) (n int64, err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func dup2(oldfd int, newfd int) (err error) {
-	_, _, e1 := Syscall(SYS_DUP2, uintptr(oldfd), uintptr(newfd), 0)
-	if e1 != 0 {
-		err = errnoErr(e1)
-	}
-	return
-}
-
-// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
-
 func EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error) {
 	var _p0 unsafe.Pointer
 	if len(events) > 0 {
diff --git a/unix/zsyscall_linux_mipsle.go b/unix/zsyscall_linux_mipsle.go
index 199e4ef4..0d4a48bb 100644
--- a/unix/zsyscall_linux_mipsle.go
+++ b/unix/zsyscall_linux_mipsle.go
@@ -46,16 +46,6 @@ func Tee(rfd int, wfd int, len int, flags int) (n int64, err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func dup2(oldfd int, newfd int) (err error) {
-	_, _, e1 := Syscall(SYS_DUP2, uintptr(oldfd), uintptr(newfd), 0)
-	if e1 != 0 {
-		err = errnoErr(e1)
-	}
-	return
-}
-
-// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
-
 func EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error) {
 	var _p0 unsafe.Pointer
 	if len(events) > 0 {
diff --git a/unix/zsyscall_linux_ppc.go b/unix/zsyscall_linux_ppc.go
index daff312f..078f1cc6 100644
--- a/unix/zsyscall_linux_ppc.go
+++ b/unix/zsyscall_linux_ppc.go
@@ -46,16 +46,6 @@ func Tee(rfd int, wfd int, len int, flags int) (n int64, err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func dup2(oldfd int, newfd int) (err error) {
-	_, _, e1 := Syscall(SYS_DUP2, uintptr(oldfd), uintptr(newfd), 0)
-	if e1 != 0 {
-		err = errnoErr(e1)
-	}
-	return
-}
-
-// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
-
 func EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error) {
 	var _p0 unsafe.Pointer
 	if len(events) > 0 {
diff --git a/unix/zsyscall_linux_ppc64.go b/unix/zsyscall_linux_ppc64.go
index aa164b2f..791efbb7 100644
--- a/unix/zsyscall_linux_ppc64.go
+++ b/unix/zsyscall_linux_ppc64.go
@@ -46,16 +46,6 @@ func Tee(rfd int, wfd int, len int, flags int) (n int64, err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func dup2(oldfd int, newfd int) (err error) {
-	_, _, e1 := Syscall(SYS_DUP2, uintptr(oldfd), uintptr(newfd), 0)
-	if e1 != 0 {
-		err = errnoErr(e1)
-	}
-	return
-}
-
-// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
-
 func EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error) {
 	var _p0 unsafe.Pointer
 	if len(events) > 0 {
diff --git a/unix/zsyscall_linux_ppc64le.go b/unix/zsyscall_linux_ppc64le.go
index f289eac7..dbc76216 100644
--- a/unix/zsyscall_linux_ppc64le.go
+++ b/unix/zsyscall_linux_ppc64le.go
@@ -46,16 +46,6 @@ func Tee(rfd int, wfd int, len int, flags int) (n int64, err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func dup2(oldfd int, newfd int) (err error) {
-	_, _, e1 := Syscall(SYS_DUP2, uintptr(oldfd), uintptr(newfd), 0)
-	if e1 != 0 {
-		err = errnoErr(e1)
-	}
-	return
-}
-
-// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
-
 func EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error) {
 	var _p0 unsafe.Pointer
 	if len(events) > 0 {
diff --git a/unix/zsyscall_linux_s390x.go b/unix/zsyscall_linux_s390x.go
index d7bf4b10..8f65b2ed 100644
--- a/unix/zsyscall_linux_s390x.go
+++ b/unix/zsyscall_linux_s390x.go
@@ -46,16 +46,6 @@ func Tee(rfd int, wfd int, len int, flags int) (n int64, err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func dup2(oldfd int, newfd int) (err error) {
-	_, _, e1 := Syscall(SYS_DUP2, uintptr(oldfd), uintptr(newfd), 0)
-	if e1 != 0 {
-		err = errnoErr(e1)
-	}
-	return
-}
-
-// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
-
 func EpollWait(epfd int, events []EpollEvent, msec int) (n int, err error) {
 	var _p0 unsafe.Pointer
 	if len(events) > 0 {
diff --git a/unix/zsyscall_linux_sparc64.go b/unix/zsyscall_linux_sparc64.go
index 8329e914..227f0f88 100644
--- a/unix/zsyscall_linux_sparc64.go
+++ b/unix/zsyscall_linux_sparc64.go
@@ -73,16 +73,6 @@ func Fadvise(fd int, offset int64, length int64, advice int) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func dup2(oldfd int, newfd int) (err error) {
-	_, _, e1 := Syscall(SYS_DUP2, uintptr(oldfd), uintptr(newfd), 0)
-	if e1 != 0 {
-		err = errnoErr(e1)
-	}
-	return
-}
-
-// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
-
 func Fchown(fd int, uid int, gid int) (err error) {
 	_, _, e1 := Syscall(SYS_FCHOWN, uintptr(fd), uintptr(uid), uintptr(gid))
 	if e1 != 0 {