Re: systemd 252.6-1 produces an Instruction fault, sysvinit works

[Frank Scheiner <frank.scheiner@web.de>]

Dear Michael,

On 21.05.23 02:11, Michael Cree wrote:
> On Thu, May 18, 2023 at 01:01:25PM +0200, Frank Scheiner wrote:
> > Welcome to Debian GNU/Linux 12 (bookworm)!
> >
> > [   11.958978] CPU 1
> > [   11.958978] systemd(1): Instruction fault 4
> > [   12.032220] pc = [<fffffc0005163bfc>]  ra = [<fffffc0005163bf8>]  ps
> > = 0000    Not tainted
> > [   12.131829] pc is at 0xfffffc0005163bfc
> > [   12.177728] ra is at 0xfffffc0005163bf8
>
> Yeah, I think I have seen this one too when I tried out the new kernel.
>
> Instruction fault 4 occurs on the execution of a reserved instruction
> (i.e. an invalid opcode) or the execution of a privileged instruction
> in user mode.
>
> Interestingly the program counter is in kernel space.  So raises the
> question is it the kernel that tried to execute an invalid instruction?
>
> Looking at the code:
>
> > [   13.559563] Code:
> > [   13.559563]  fffffc00
> > [   13.582024]  00000000
> > [   13.610344]  00000000
> > [   13.638664]  05163bfc
> > [   13.666985]  fffffc00
> > [   13.695305]  02871148
> > [   13.723625] <fffffc00>
> > [   13.751946]  00000000
> > [   13.779289]
>
> These do not appear to be valid code.  They look more like addresses.
> It has the appearance that the kernel has jumped into data and tried
> to execute it as code!

Thanks for your explanations and analysis, that's more than helpful.

> Maybe report it to the Linux Kernel Mail List?

The thread is here:

https://marc.info/?l=linux-alpha&m=168474811430816&w=2

I would have posted a link to the debian-alpha mailing list, but the
assumed greylisting there prevented my message to appear there yet.

Cheers,
Frank