FS#75478 - [linux] Modifications in 5.18.15 addressing Retbleed may prevent booting on AMD CPUs

Attached to Project: Arch Linux
Opened by Peter Mattern (krabat) - Monday, 01 August 2022, 09:34 GMT
Last edited by Toolybird (Toolybird) - Saturday, 10 June 2023, 23:07 GMT
Task Type Bug Report
Category Packages: Core
Status Closed
Assigned To Tobias Powalowski (tpowa)
Jan Alexander Steffens (heftig)
David Runge (dvzrv)
Architecture All
Severity Critical
Priority Normal
Reported Version
Due in Version Undecided
Due Date Undecided
Percent Complete 100%
Votes 12
Private No


5.18.15 replaced IBRS with IBPB to better handle the Retbleed vulnerability, but didn't introduce a check, whether IBPB is available. This may prevent booting on AMD CPUs lacking IBPB.
The problem affects both virtual machines [1] and real hardware [2] (and some more threads in the forums).

The offending commit is 4a15f0d6 (stable) / 28a99e95 (mainline), see e. g. [3].

Workarounds are downgrading to 5.18.14 or using kernel command line parameter spectre_v2=off.

Solutions available so far are reverting the said commit or applying the fix proposed in [1] (neither implemented in 5.19 yet).

[1] https://lore.kernel.org/lkml/20220728122602.2500509-1-cascardo%40canonical.com/T/
[2] https://bbs.archlinux.org/viewtopic.php?id=278535
[3] https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.18.15
This task depends upon

Closed by  Toolybird (Toolybird)
Saturday, 10 June 2023, 23:07 GMT
Reason for closing:  Fixed
Additional comments about closing:  See comments
Comment by Peter Mattern (krabat) - Monday, 01 August 2022, 09:37 GMT
Link [1] in should have been20220728122602.2500509-1-cascardo@canonical.com/T/"> https://lore.kernel.org/lkml/20220728122602.2500509-1-cascardo@canonical.com/T/
Comment by Peter Mattern (krabat) - Monday, 01 August 2022, 09:38 GMT
Sigh. Apparently some automagic formatting by FlySpray!?
Comment by loqs (loqs) - Monday, 01 August 2022, 14:31 GMT Comment by Alex Cendejas (Acente25) - Monday, 01 August 2022, 15:02 GMT
I experienced this issue too. Downgraded to 5.18.14.
CPU: AMD PRO A10-9700E R7
Kernel: linux-zen 5.18.15.zen1-1
Comment by Jhon Caicedo (jhcaiced) - Tuesday, 02 August 2022, 21:22 GMT
I have experienced this issue too.
CPU: AMD Ryzen 5 1600 Six-Core Processor

- Adding spectre_v2=off to the kernel parameters worked for me with linux 5.18.15.arch1-2
Comment by Doug Newgard (Scimmia) - Wednesday, 03 August 2022, 11:12 GMT
5.18.16 and 5.15.59 are out, and do indeed include the patches for this.
Comment by nl6720 (nl6720) - Wednesday, 03 August 2022, 16:25 GMT
linux 5.18.16.arch1-1 fixes the issue for me on AMD Athlon 5350.
Comment by Lichtprotoss (Lichtprotoss) - Wednesday, 03 August 2022, 20:50 GMT

linux 5.18.16.arch1-1 does not fix it for AMD A6-1450. It does not boot with the error as described above. Rolling back to linux 5.18.14-arch1-1 works.

Thanks & Best Regards
Comment by Lichtprotoss (Lichtprotoss) - Wednesday, 03 August 2022, 21:01 GMT

Thanks for opening again. I found the posting [1] in our Forum and this actually works for AMD A6-1450:

With linux 5.18.14-arch1-1, add "spectre_v2=off" to the boot command line, see [2].

Afterwards, linux 5.18.15.arch1-2 works, and also linux 5.18.16.arch1-1 works.

Hope it makes sense to you.

[1] https://bbs.archlinux.org/viewtopic.php?pid=2049636#p2049636
[2] https://wiki.archlinux.org/title/Kernel_parameters#Configuration
Comment by Jhon Caicedo (jhcaiced) - Wednesday, 03 August 2022, 23:00 GMT
CPU: AMD Ryzen 5 3600
linux 5.18.16.arch1-1, this version works for me without using spectre_v2=off

Comment by NgoHuy (Severus) - Friday, 05 August 2022, 09:09 GMT
@jhcaiced Ryzen 5 3600 is not affected by this issue. Old hardware only.
Comment by Ewout van Mansom (ewout) - Friday, 05 August 2022, 11:30 GMT
Can confirm. Also happens here on a Lenovo G505 with AMD A4-5000 with kernel 5.18.15.
No problems on 5.18.16.
Comment by Kálmán Endre (LordEndre) - Friday, 05 August 2022, 11:51 GMT
Machine with A8-5500B failed to boot with 5.18.15.
With 5.18.16 works fine.
Comment by Christian Hesse (eworm) - Friday, 05 August 2022, 21:49 GMT
Pushed linux-lts 5.15.59-1 to fix it for lts version.
Comment by Melissa Loos (Kaiyazeera) - Monday, 08 August 2022, 01:01 GMT
linux 5.18.16.arch1-1 works for AMD Athlon(tm) X4 880K Quad Core Processor × 2 (5.18.15 does not work with this CPU)