Red Hat Bugzilla – Bug 145608
microcode_ctl uses wrong device path
Last modified: 2015-01-04 17:15:56 EST
Description of problem:
Loading the microcode kernel module creates /dev/microcode and the
symlink /dev/cpu/microcode, but /etc/init.d/microcode_ctl looks for
/dev/cpu/0/microcode, and then exits when the device isn't found.
Changing DEVICE in /etc/init.d/microcode_ctl fixes the problem.
Steps to Reproduce:
1. modprobe microcode
2. /etc/init.d/microcode_ctl start
/etc/init.d/microcode_ctl: microcode device /dev/cpu/0/microcode
Confirmed on two different single CPU systems (Celeron-Mendocino and
harald, microcode_ctl is the *only* thing that uses this dev node, so this can't
break anything else -- Can we kill the symlinks, and just put the device nodes
directly in the directories please ?
sidenote: this does actually work fine for me, so I've no idea why it broke in
testing, but the current behaviour is clearly suboptimal. I can only think that
the /dev/microcode was something that we shipped many many years ago, but as I
mentioned above, nothing else uses it, so we don't need to worry about back
The correct location would be /dev/cpu/microcode, which is a) what we've done in
FC4, and b) what is set upstream. However if we change to that, we'll also have
to do a kernel-utils errata in parallel.
ok, back to /dev/cpu/0/microcode then...
just to be sure we're on the same page -- /dev/cpu/microcode is fine for FC4 and
should stay that way. Sadly I didn't get to make the necessary changes in RHEL4
before we froze.
2.4-13.1.56 should have this fixed.
this doesn't to appear to be fixed in kernel-utils-2.4-13.1.57,
as /etc/init.d/microcode_ctl still shows:
instead of expected (from comment #1):
... changing status to FAILS_QA ...
fixed in .60 (building now)
Fix confirmed with kernel-utils-2.4-13.1.61 which is included in the latest U1
Verified in U1. The bug is fixed.
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on the solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.