When updating yum or trying to install new packages or regular updates on a CentOS 6 system, you may run into an error like the following:
root@server [~]# yum update Freeing read locks for locker 0x5: 425388/140510239045376 Freeing read locks for locker 0x7: 425388/140510239045376 Freeing read locks for locker 0x8: 425388/140510239045376 Freeing read locks for locker 0x15: 425388/140510239045376 Freeing read locks for locker 0x17: 425388/140510239045376 Loaded plugins: fastestmirror, rhnplugin Setting up Update Process Determining fastest mirrors Illegal instruction
This is likely caused by a known bug in the nss-softokn package as described here: https://bugs.centos.org/view.php?id=10930
To resolve this, simply run the following command:
export NSS_DISABLE_HW_AES=1; yum upgrade
Once you have updated that package as part of the yum upgrade, the bug will be patched and you won't see it again.