Bug 168417

Summary: duplicate microcode device nodes in /dev/cpu/
Product: Red Hat Enterprise Linux 4 Reporter: Nalin Dahyabhai <nalin>
Component: MAKEDEVAssignee: Nalin Dahyabhai <nalin>
Status: CLOSED ERRATA QA Contact: Brock Organ <borgan>
Severity: medium Docs Contact:
Priority: medium    
Version: 4.0CC: bjohnson, davej, gordon.jin, notting, selinux, tao, trondeg, yekkim
Target Milestone: ---   
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: RHBA-2006-0193 Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2006-03-07 18:20:35 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 63928    
Bug Blocks: 168430    

Description Nalin Dahyabhai 2005-09-15 20:28:31 UTC
+++ This bug was initially created as a clone of Bug #63928 +++

It seems wrong to have multiple aliases (/dev/cpu/0..15/microcode) for the same
device node (major 10, minor 184).  Why is it done this way?  Would it be better
to have unique microcode device nodes for each processor instead of just using
/dev/cpu/microcode?  Is this something I should change in the official devices.txt?

Thanks,
John Cagle
(wearing my LANANA hat)

-- Additional comment from nalin on 2004-08-25 20:36 EST --
I couldn't hazard a guess.  The init script which calls microcode_ctl
on my system is in kernel-utils, maybe there's some idea there.

-- Additional comment from davej on 2004-10-25 23:20 EST --
I've never figured out why we deviated away from upstream here.
Our microcode_ctl has a patch to change reading the file from /dev/cpu/microcode
to /dev/cpu/0/microcode.  It makes no sense to me as

a) We only do it for cpu #0
b) The driver patches every CPU in the system, so multiple nodes don't make sense.

We could drop that patch and fix up udev in FC4 / RHEL4.


-- Additional comment from davej on 2005-01-10 19:51 EST --
as of tomorrow, microcode_ctl in rawhide will use the upstream /dev/cpu/microcode.
Harald, please adjust udev accordingly.


-- Additional comment from yekkim on 2005-01-12 14:21 EST --
If udev-050-1 was the 'adjusted' udev for this bug, then the commented
line in /etc/makedev.d/linux-2.6.x:

#c $ROOT                 10 184  1   1 cpu/microcode

should be uncommented. 

Likewise, the uncommented line in /etc/makedev.d/redhat:

c $ROOT                 10 184  0  16 cpu/%d/microcode

should be commented.

-- Additional comment from harald on 2005-01-20 11:17 EST --
*** Bug 144915 has been marked as a duplicate of this bug. ***

-- Additional comment from nalin on 2005-01-20 18:57 EST --
*** Bug 144887 has been marked as a duplicate of this bug. ***

-- Additional comment from harald on 2005-02-10 06:20 EST --
*** Bug 147657 has been marked as a duplicate of this bug. ***

-- Additional comment from harald on 2005-02-10 06:20 EST --
*** Bug 145861 has been marked as a duplicate of this bug. ***

-- Additional comment from harald on 2005-02-10 06:21 EST --
*** Bug 146292 has been marked as a duplicate of this bug. ***

-- Additional comment from gordon.jin on 2005-04-06 22:25 EST --
This fix is not in RHEL4-U1-beta.

In RHEL4-U1-beta:
microcode_ctl has been changed to use /dev/cpu/microcode,
but shipped MAKEDEV-3.15-2 doesn't contain the corresponding fix in Comment#4.

Can you get this fixed in RHEL4-U1?

Comment 1 Nalin Dahyabhai 2005-09-15 20:30:51 UTC
Cloned for tracking against RHEL.

Comment 7 Daniel Riek 2006-01-11 02:15:53 UTC
*** Bug 177469 has been marked as a duplicate of this bug. ***

Comment 12 Nalin Dahyabhai 2006-01-26 22:00:59 UTC
*** Bug 177488 has been marked as a duplicate of this bug. ***

Comment 13 Red Hat Bugzilla 2006-03-07 18:20:35 UTC
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.

http://rhn.redhat.com/errata/RHBA-2006-0193.html