#Kernel Command Line "amd_iommu=force_isolation" blank screen #10

thereisnoanderson commented 2025年03月10日 05:57:38 +01:00

since Fedora 6.13.4-200.fc41 "amd_iommu=force_isolation" arg on system causing a blank screen after grub_timeout.

last working kernel using that arg: 6.12.15-200.fc41.

any correlation to "AMD microcode signature verification vulnerability (CVE-2024-56161)" ?

since Fedora 6.13.4-200.fc41 "amd_iommu=force_isolation" arg on system causing a blank screen after grub_timeout. last working kernel using that arg: 6.12.15-200.fc41. any correlation to "AMD microcode signature verification vulnerability (CVE-2024-56161)" ?

ContentedGoat commented 2025年03月10日 05:59:34 +01:00

yes that argument breaks boot on systems recent amd gpu

it isn't related to microcode or security issue

I reported it here https://bugzilla.redhat.com/show_bug.cgi?id=2349003

yes that argument breaks boot on systems recent amd gpu it isn't related to microcode or security issue I reported it here https://bugzilla.redhat.com/show_bug.cgi?id=2349003

thereisnoanderson commented 2025年03月10日 06:06:22 +01:00

awesome! THANK YOU

awesome! THANK YOU

thereisnoanderson commented 2025年04月24日 01:37:32 +02:00

we back on track!

we back on track!

thereisnoanderson commented 2025年04月24日 12:46:27 +02:00

false positive, we are not back on track...

false positive, we are not back on track...

lucasmz commented 2025年08月25日 19:56:39 +02:00

On mine it doesn't break boot, ryzen 5600g, instead, it actually causes random crashes while using the system which end up freezing everything

On mine it doesn't break boot, ryzen 5600g, instead, it actually causes random crashes while using the system which end up freezing everything

realdeimos commented 2025年11月18日 09:37:50 +01:00

I ran into this issue with the latest Fedora in a qemu/kvm VM. Installed brace via rpm, rebooted, screen goes blank during boot. As soon as the kernel loads, before it gets to the LUKS unlock screen, it blanks. Editing the command line in grub prompt doesn't seem to work.

I ran into this issue with the latest Fedora in a qemu/kvm VM. Installed brace via rpm, rebooted, screen goes blank during boot. As soon as the kernel loads, before it gets to the LUKS unlock screen, it blanks. Editing the command line in grub prompt doesn't seem to work.

ContentedGoat commented 2025年11月18日 09:47:06 +01:00

@realdeimos
are you sure it was this arg? I don't think it is possible to have any effect in a VM.
and current brace prevents adding this arg to a host machine if it detects an amd gpu

I have seen some unrelated issues where a VM blanks/freezes during boot such as when using virgl and the window isn't focused or when using the hardened_malloc on qemu with certain paravirt drivers.

@realdeimos are you sure it was this arg? I don't think it is possible to have any effect in a VM. and current brace prevents adding this arg to a host machine if it detects an amd gpu I have seen some unrelated issues where a VM blanks/freezes during boot such as when using virgl and the window isn't focused or when using the hardened_malloc on qemu with certain paravirt drivers.

realdeimos commented 2025年11月19日 08:24:18 +01:00

@ContentedGoat wrote in #10 (comment):

@realdeimos are you sure it was this arg? I don't think it is possible to have any effect in a VM. and current brace prevents adding this arg to a host machine if it detects an amd gpu

The short answer is, I'm not sure it's this line. I finally managed to get into grub long enough to find the line is not there. However, I've edited it half blind a few times so not sure what was there.

I have seen some unrelated issues where a VM blanks/freezes during boot such as when using virgl and the window isn't focused or when using the hardened_malloc on qemu with certain paravirt drivers.

Happy to open a new issue if this is more relevant. All I know is that after installing brace via rpm from your CI/build the other day, the Fedora VM blanks after a very fast flash of the boot sequence. Happy to try to debug it or just wipe and re-install the VM and see what happens.

@ContentedGoat wrote in https://codeberg.org/divested/brace/issues/10#issuecomment-8329764: > @realdeimos are you sure it was this arg? I don't think it is possible to have any effect in a VM. and current brace prevents adding this arg to a host machine if it detects an amd gpu The short answer is, I'm not sure it's this line. I finally managed to get into grub long enough to find the line is not there. However, I've edited it half blind a few times so not sure what was there. > I have seen some unrelated issues where a VM blanks/freezes during boot such as when using virgl and the window isn't focused or when using the hardened_malloc on qemu with certain paravirt drivers. Happy to open a new issue if this is more relevant. All I know is that after installing brace via rpm from your CI/build the other day, the Fedora VM blanks after a very fast flash of the boot sequence. Happy to try to debug it or just wipe and re-install the VM and see what happens.

ContentedGoat commented 2025年11月19日 08:45:11 +01:00

@realdeimos
can you confirm it boots if you switch graphics to qxl?

@realdeimos can you confirm it boots if you switch graphics to qxl?

realdeimos commented 2025年11月19日 17:18:24 +01:00

I'm using spice by default, I think that's also called qxl?

I'm using spice by default, I think that's also called qxl?