Re: [PATCH v2] gzio: Avoid spurious failures

[Daniel Kiper]

On Tue, Oct 31, 2023 at 08:53:41PM +0100, Vladimir 'phcoder' Serbinenko wrote:
> On Tue, Oct 31, 2023 at 7:28 PM Jason Andryuk <jandryuk@gmail.com> wrote:
> >
> > grub_gzio_read_real() uses grub_errno to identify decompression failures
> > when the function completes.  Its callees in gzio.c are void-returning
> > functions that set grub_errno on their exit paths.
> >
> > A Fedora 38 machine was observed to fail `multiboot2 /xen.gz` with
> > "premature end of file".  xen.gz was well formed and could be
> > successfully gunzip-ed in Linux.
> >
> > The TPM is flaky and produces errors when the verifier tries to extend
> > PCRs with measurements.  Logs show "Unkown TPM error" and grub_errno is
> > set to GRUB_ERR_UNKNOWN_DEVICE.  This pre-existing grub_errno causes an
> > otherwise successful grub_gzio_read_real() call to return error.
> This bus is likely to create other problems as well. Why not fix it?
> If this error is meant to be ignored rather than stop loading, then it
> should be discarded early, possibly printed. If it should stop loading
> then this should really stop and not even get here

Jason, this makes me wonder what GRUB version you use. Do you have this
commit afdef4a56 (tpm: Enable boot despite unknown firmware failure)?
I am not sure I did not ask you about this earlier...

Daniel