objdump fails to disassemble rdrand

[Jeffrey Walton]

`objdump --disassemble` is not producing expected output for the rdrand instruction. The same test using rdseed appears to be ok.

$ cat test.S
        global NASM_RDRAND
        section .text
        align 16

NASM_RDRAND:
        rdrand rax
        jnc NASM_RDRAND
        ret

$ nasm -f elf64 test.S -o test.o

$ objdump --disassemble test.o

test.o: file format elf64-x86-64

Disassembly of section .text:

0000000000000000 <NASM_RDRAND>:
   0: 48 0f 07 sysretq
   3: f0 73 fa lock jae 0 <NASM_RDRAND>
   6: c3 retq

****************************************

$ objdump -v
GNU objdump (GNU Binutils for Ubuntu) 2.26.1
Copyright (C) 2015 Free Software Foundation, Inc.

$ uname -a
Linux qotom 4.4.0-53-generic #74-Ubuntu SMP Fri Dec 2 15:59:10 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux

$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 16.04.2 LTS
Release: 16.04
Codename: xenial

****************************************

$ apt-cache show binutils
Package: binutils
Priority: optional
Section: devel
Installed-Size: 13328
Maintainer: Ubuntu Developers <email address hidden>
Original-Maintainer: Matthias Klose <email address hidden>
Architecture: amd64
Version: 2.26.1-1ubuntu1~16.04.3
Replaces: binutils-gold (<< 2.20.51.20100415), binutils-mingw-w64-i686 (<< 2.23.52.20130612-1+3), binutils-mingw-w64-x86-64 (<< 2.23.52.20130612-1+3)
Provides: binutils-gold, elf-binutils
Depends: libc6 (>= 2.14), zlib1g (>= 1:1.2.0)
Suggests: binutils-doc (>= 2.26.1-1ubuntu1~16.04.3)
Conflicts: binutils-gold (<< 2.20.51.20100415), binutils-mingw-w64-i686 (<< 2.23.52.20130612-1+3), binutils-mingw-w64-x86-64 (<< 2.23.52.20130612-1+3), elf-binutils, gas, modutils (<< 2.4.19-1)
Breaks: binutils-mingw-w64-i686 (<< 2.23.52.20130612-1+3), binutils-mingw-w64-x86-64 (<< 2.23.52.20130612-1+3)
Filename: pool/main/b/binutils/binutils_2.26.1-1ubuntu1~16.04.3_amd64.deb
Size: 2310310
MD5sum: 04b00c4b3ba1d86afbb679b63476d05a
SHA1: d15740302cd64dea8d4d853aa660b0bba3bb9105
SHA256: 1db714433416a0d9bd49f1174e85b55f65597fe337116267ad5ad16fc7f3e2dd
Description-en: GNU assembler, linker and binary utilities
 The programs in this package are used to assemble, link and manipulate
 binary and object files. They may be used in conjunction with a compiler
 and various libraries to build programs.
Description-md5: fde49b4cfeaad346a6e094f973da28d7
Bugs: https://bugs.launchpad.net/ubuntu/+filebug
Build-Essential: yes
Origin: Ubuntu
Supported: 5y
Task: ubuntu-desktop, ubuntu-usb, kubuntu-desktop, kubuntu-full, edubuntu-desktop, edubuntu-usb, xubuntu-core, xubuntu-desktop, mythbuntu-frontend, mythbuntu-desktop, mythbuntu-backend-slave, mythbuntu-backend-master, mythbuntu-backend-master, lubuntu-live, ubuntustudio-desktop-core, ubuntustudio-desktop, ubuntu-gnome-desktop, ubuntu-touch, ubuntukylin-desktop, ubuntu-mate-core, ubuntu-mate-desktop, ubuntu-mate-cloudtop

Package: binutils
Priority: optional
Section: devel
Installed-Size: 13332
Maintainer: Ubuntu Core developers <email address hidden>
Original-Maintainer: Matthias Klose <email address hidden>
Architecture: amd64
Version: 2.26-8ubuntu2
Replaces: binutils-gold (<< 2.20.51.20100415), binutils-mingw-w64-i686 (<< 2.23.52.20130612-1+3), binutils-mingw-w64-x86-64 (<< 2.23.52.20130612-1+3)
Provides: binutils-gold, elf-binutils
Depends: libc6 (>= 2.14), zlib1g (>= 1:1.2.0)
Suggests: binutils-doc (>= 2.26-8ubuntu2)
Conflicts: binutils-gold (<< 2.20.51.20100415), binutils-mingw-w64-i686 (<< 2.23.52.20130612-1+3), binutils-mingw-w64-x86-64 (<< 2.23.52.20130612-1+3), elf-binutils, gas, modutils (<< 2.4.19-1)
Breaks: binutils-mingw-w64-i686 (<< 2.23.52.20130612-1+3), binutils-mingw-w64-x86-64 (<< 2.23.52.20130612-1+3)
Filename: pool/main/b/binutils/binutils_2.26-8ubuntu2_amd64.deb
Size: 2302996
MD5sum: 94899981678c27e438f85e554746deff
SHA1: 3197b042645a7ee607391f873a4f7012d888bf3c
SHA256: 053b01a92bdb39329c199e85a621910a9d81ad4ec9d65d9e7e59ff4ab2709d55
Description-en: GNU assembler, linker and binary utilities
 The programs in this package are used to assemble, link and manipulate
 binary and object files. They may be used in conjunction with a compiler
 and various libraries to build programs.
Description-md5: fde49b4cfeaad346a6e094f973da28d7
Bugs: https://bugs.launchpad.net/ubuntu/+filebug
Build-Essential: yes
Origin: Ubuntu
Supported: 5y
Task: ubuntu-desktop, ubuntu-usb, kubuntu-desktop, kubuntu-full, edubuntu-desktop, edubuntu-usb, xubuntu-core, xubuntu-desktop, mythbuntu-frontend, mythbuntu-desktop, mythbuntu-backend-slave, mythbuntu-backend-master, mythbuntu-backend-master, lubuntu-live, ubuntustudio-desktop-core, ubuntustudio-desktop, ubuntu-gnome-desktop, ubuntu-touch, ubuntukylin-desktop, ubuntu-mate-core, ubuntu-mate-desktop, ubuntu-mate-cloudtop

[Jeffrey Walton (noloader)]

The disassembly of rdrand looks ok in 2.26.1-1ubuntu1~16.04.3.

Thanks.

[Matthias Klose (doko)]

thanks for validating. closing the issue