Trusty cannot load microcode for family 17h AMD processors
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
linux (Ubuntu) |
Invalid
|
Critical
|
Tyler Hicks | ||
Trusty |
Fix Released
|
Undecided
|
Tyler Hicks |
Bug Description
[Impact]
AMD has recently updated the microcode in the linux-firmware tree for family 17h processors to address Spectre variant 2. The Trusty 3.13 kernel cannot load the microcode because it is missing a backport of upstream patch f4e9b7af0cd58dd
[Test Case (option 1)]
Test must be done on a 17h family processor:
1) Take note of the microcode version before applying updated microcode:
$ sudo cat /sys/devices/
0x8001227
2) Get updated amd64-microcode package from the Ubuntu Security Team. Install it and reboot machine.
3) Verify that the microcode version has changed.
[Test Case (option 2)]
Alternate test case (useful in the situation that the test system is already running the latest microcode revision due to a BIOS update):
1) Fetch the latest 17h family microcode revision from here (you may want to verify the signature):
2) Move it into /lib/firmware/
3) Force a microcode reload:
$ echo 1 | sudo tee /sys/devices/
4) Verify that the following error message is *not* in your syslog:
May 30 04:22:55 lodygin kernel: [ 388.290105] microcode: patch size mismatch
May 30 04:22:55 lodygin kernel: [ 388.290149] microcode: Patch-ID 0x08001227: size mismatch.
[Regression Potential]
The regression potential to the kernel revolves around the fact that the IBRS/IBPB implementation in the 3.13 kernel may not have been put through its paces yet due to a lack of available microcode updates. There could be a latent bug present that is uncovered.
description: | updated |
description: | updated |
Changed in linux (Ubuntu Trusty): | |
status: | In Progress → Fix Committed |
The upstream fix has been applied to Xenial and newer kernels. This bug is only for Trusty.