Red Hat Bugzilla – Bug 157672
/dev/cpu/microcode isn't created
Last modified: 2015-01-04 17:19:33 EST
This seems to be a popular thing to get wrong ;) From microcode_ctl:s changelog: * Fri Jan 21 2005 Dave Jones <davej@redhat.com> - Create/remove the /dev/cpu/microcode dev node as needed. Which would explain why udev no longer creates the device node (I found a FC3 machine to check the old behaviour. The device node is created in start_udev). However! Further up in microcode_ctl:s changelog there is: * Tue Jan 25 2005 Dave Jones <davej@redhat.com> - Drop the node creation/deletion change from previous release. It'll cause grief with selinux, and was a hack to get around a udev shortcoming that should be fixed properly. But udev hasn't been fixed. So now we're in the situation where microcode updates simply do not work. I don't really care who creates this device node, just as long as someone does it :) Versions: udev-057-5 microcode_ctl-1.11-1.21
Indeed, I have the same behaviour with RHEL4up1. Does anybody know when this would be solved?
rawhide does the right thing right now. (14:16:21:davej@nwo:~)$ ll /dev/cpu total 0 drwxr-xr-x 2 root root 60 Aug 7 10:34 0/ drwxr-xr-x 2 root root 60 Aug 7 10:34 1/ drwxr-xr-x 2 root root 60 Aug 7 10:34 2/ drwxr-xr-x 2 root root 60 Aug 7 10:34 3/ (14:16:41:root@nwo:~)# modprobe microcode (14:16:42:root@nwo:~)# ll /dev/cpu total 0 drwxr-xr-x 2 root root 60 Aug 7 10:34 0/ drwxr-xr-x 2 root root 60 Aug 7 10:34 1/ drwxr-xr-x 2 root root 60 Aug 7 10:34 2/ drwxr-xr-x 2 root root 60 Aug 7 10:34 3/ crw-rw---- 1 root root 10, 184 Aug 16 14:16 microcode Closing this out. The RHEL4 bug is being tracked elsewhere. No changes need to occur in Fedora at this time.
[root@poseidon ~]# service microcode_ctl start /etc/init.d/microcode_ctl: microcode device /dev/cpu/microcode doesn't exist? I think you misunderstood the problem. Previously udev created the node _before_ the module was loaded. So when someone accessed the device node the module got loaded. Or is it required installtion procedure to hack initscripts and add a modprobe early on? ;)
microcode init script was missing a fix that I added to the RHEL4 tree already which prevented this from working. It should work in tomorrows rawhide.