Re: [PATCH] x86/boot: Reject truncated acpi_rsdp= values

[Borislav Petkov]

On Fri, Jun 19, 2026 at 09:57:58AM +0200, Thorsten Blum wrote:
> Are you perhaps appending nokaslr?

Yes, removed it. Same thing.

> With the latest Linus tree, defconfig, and CONFIG_MEMORY_HOTREMOVE=y,
> this crashes reproducibly for me, but only when KASLR is not disabled:
> 
> qemu-system-x86_64 -nographic -no-reboot -kernel arch/x86/boot/bzImage -append "console=ttyS0 acpi_rsdp=0x0123456789abcdefx"

As said, efistub entry point bypassing get_cmdline_acpi_rsdp():

...
-drive if=pflash,format=raw,unit=0,file=/home/boris/kvm/debian/uefi/OVMF_CODE_4M-sid-uefi.fd,readonly=on
-drive if=pflash,format=raw,unit=1,file=/home/boris/kvm/debian/uefi/OVMF_VARS_4M-sid-uefi.fd,readonly=of
...

So I can't reproduce it.

So, in order not to waste any more time with this silly thing: if we're going
to do something here, then that something better warn users that rsdp_addr
parsing didn't go as planned. But not silently turn it to 0. It does that now
but since you care so much, then fix it right pls.

Thx.

-- 
Regards/Gruss,
    Boris.

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