Segmentation faults with Nvidia 349.16 on Arch Linux

26 April 2015

I recently started a fresh install of Arch Linux and everything was going well until I installed the NVIDIA proprietary driver.

# pacman -S nvidia nvidia-libgl

Opening any application would then cause a segmentation fault, although the application would still open. I wasted a few hours convinced that this was problem with the proprietary driver.

I found the answer on the Arch forums and it turns out to be a problem with the microcode for my Intel i5 processor (and others). I can't remember the topic I looked at, only that it was thanks to Scimmia.

$ dmesg | grep microcode
microcode: CPU0 sig=0x306c3, pf=0x2, revision=0x1c
microcode: CPU1 sig=0x306c3, pf=0x2, revision=0x1c
microcode: CPU2 sig=0x306c3, pf=0x2, revision=0x1c
microcode: CPU3 sig=0x306c3, pf=0x2, revision=0x1c

Updating the microcode

The updated Intel microcode is packaged as intel-ucode in the Arch repositories, so it is simply a case of installing it.

# pacman -S intel-ucode

The final step is to instruct the boot loader, gummiboot in my case, to use the microcode.

File: /boot/loader/entries/arch.conf

title   Arch Linux
linux   /vmlinuz-linux
initrd /intel-ucode.img
initrd  /initramfs-linux.img
options root=/dev/sdb2 rw

Turning it off and back on again

I rebooted and checked to see that the microcode had been updated.

$ dmesg | grep microcode
CPU0 microcode updated early to revision 0x1c, date = 2014-07-03
CPU1 microcode updated early to revision 0x1c, date = 2014-07-03
CPU2 microcode updated early to revision 0x1c, date = 2014-07-03
CPU3 microcode updated early to revision 0x1c, date = 2014-07-03
microcode: CPU0 sig=0x306c3, pf=0x2, revision=0x1c
microcode: CPU1 sig=0x306c3, pf=0x2, revision=0x1c
microcode: CPU2 sig=0x306c3, pf=0x2, revision=0x1c
microcode: CPU3 sig=0x306c3, pf=0x2, revision=0x1c
microcode: Microcode Update Driver: v2.00 <tigran@aivazian.fsnet.co.uk>, Peter Oruba

I have had no further problems with segmentation faults.