Linux-libre 3.1 update & kernel panics

If you updated to linux-libre-3.1-2 this days, please make sure your mkinitcpio version is 0.7.5. Some users are experiencing problems because pacman refuses to update from 1:0.7.4 to 0.7.5. If that's your case, please force the upgrade manually:

# pacman -Sy mkinitcpio
# mkinitcpio -p linux-libre

If you missed the message and rebooted, you'll have to do this on a chroot. Our manual installation guide ("Prepare chroot") is helpful for chrooting into your system from a live CD.