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[SRU,J,0/2] Duplicate Device_dax ids Created and hence Probing is Failing

Message ID 20230922170910.12844-1-michael.reed@canonical.com
Headers show
Series Duplicate Device_dax ids Created and hence Probing is Failing | expand

Message

Michael Reed Sept. 22, 2023, 5:09 p.m. UTC 
From: Michael Reed <Michael.Reed@canonical.com>

[Impact]
Description of problem:

Observed device_dax related probe errors in dmesg when HBM CPU is set to flat mode. Duplicate device_dax ids were created and hence probing is failing.

How reproducible:
Frequently

Version-Release
Release: 22.04.2, 22.10

[Test Case]

Steps to Reproduce:
1. Set HBM cpu to flat mode in memory settings in BIOS.
2. Boot to the OS.
3. Perform OS warm boot cycle test.
4. Observe the dax2.0/dax3.0/dax4.0/dax5.0 probe error.

Actual results:
Observed device_dax related errors in dmesg, device Dax is creating dummy/duplicate devices and probe failing.

Expected results:
Dummy/duplicate devices should not create.

[Fix]
Upstream Fix
https://lore.kernel.org/linux-mm/166890823379.4183293.15333502171004313377.stgit@dwillia2-xfh.jf.intel.com/T/

By default this is enabled, but it is causing an issue reconfiguring device dax memory, thus
it is being disabled.
Disable CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE
Set CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE=N

[Where problems could occur]

[Other Info]
Dan Williams (1):
  device-dax: Fix duplicate 'hmem' device registration

Michael Reed (1):
  UBUNTU: [Config] CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE

 debian.master/config/annotations |  2 +-
 drivers/dax/hmem/device.c        | 26 ++++++++++++++++----------
 2 files changed, 17 insertions(+), 11 deletions(-)