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
Opened by Peter Mattern (krabat) - Monday, 01 August 2022, 09:34 GMT
Last edited by Toolybird (Toolybird) - Saturday, 10 June 2023, 23:07 GMT
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Details
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
Saturday, 10 June 2023, 23:07 GMT
Reason for closing: Fixed
Additional comments about closing: See comments
Sorry.
Replace @ with %40 to prevent flyspray misdetecting a link as an email.
[1] https://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git/patch/queue-5.18/x86-bugs-do-not-enable-ibpb-at-firmware-entry-when-ibpb-is-not-available.patch?id=28f1f367e63c54232b7911538de0faf1af909712
[2] https://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git/patch/queue-5.15/x86-bugs-do-not-enable-ibpb-at-firmware-entry-when-ibpb-is-not-available.patch?id=f3ee948c79ff504ce13de637d41c6b7cfcf9e484
CPU: AMD PRO A10-9700E R7
Kernel: linux-zen 5.18.15.zen1-1
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
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
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
linux 5.18.16.arch1-1, this version works for me without using spectre_v2=off
No problems on 5.18.16.
With 5.18.16 works fine.