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Created attachment 555034 [details]
/var/log/messaes excerpt for rmmod amd64_edac_mod

Description of problem:
Boot kernel 2.6.32-220.2.1.el6.x86_64 and unload EDAC modules by
  rmmod amd64_edac_mod edac_mce_amd edac_core
Kernel will inhibit soft lockup BUG and will become unresponsive.

Version-Release number of selected component (if applicable):
kernel-2.6.32-220.2.1.el6.x86_64
kernel-firmware-2.6.32-220.2.1.el6.noarch

How reproducible: always

Steps to Reproduce:
1. Boot kernel 2.6.32-220.2.1.el6.x86_64 on 
   Supermicro H8DGT-HF BIOS Date: 11/09/2011 Rev: 2.0a
   (also tested: BIOS Rev: 1.0c)
   and 2 x Opteron 6128
      vendor_id : AuthenticAMD
      cpu family: 16
      model     : 9
      model name: AMD Opteron(tm) Processor 6128
      stepping  : 1
   and 64 GB RAM.
2. modprobe amd64_edac_mod edac_mce_amd edac_core
   (if modules are not auto-loaded)
3. rmmod amd64_edac_mod
  
Actual results: see attachment with excerpt of /var/log/messsages.

Expected results: unload the module, no crash

Additional info: works fine with 2.6.32-131.21.1.el6.x86_64

Created attachment 557840 [details]
/var/log/messages excerpt for rmmod amd64_edac_mod after kernel update

update from 2.6.32-220.2.1.el6.x86_64 to 2.6.32-220.4.1.el6.x86_64 does not fix the bug

Since RHEL 6.3 External Beta has begun, and this bug remains
unresolved, it has been rejected as it is not proposed as
exception or blocker.

Red Hat invites you to ask your support representative to
propose this request, if appropriate and relevant, in the
next release of Red Hat Enterprise Linux.

update to 6.4 and to kernel-2.6.32-358.14.1.el6.x86_64 does not fix the bug

rmmod amd64_edac_mod
-> shell freezes
-> edac_core depdendy -1
-> module amd64_edac_mod not removed
-> after ~1 minute node freezes completely

Created attachment 786463 [details]
/var/log/messages excerpt for rmmod amd64_edac_mod after kernel and distro update

This is fixed by BZ#831127 which should be in 6.5.

*** This bug has been marked as a duplicate of bug 831127 ***