Re: [PATCH 1/2] x86: Check return values from early_memremap calls

[Borislav Petkov <bp@xxxxxxxxx>]

Adding Xen and Jailhouse people and MLs to Cc.

Folks, thread starts here:

https://lore.kernel.org/r/1650035401-22855-1-git-send-email-ross.philipson@xxxxxxxxxx

On Fri, Apr 15, 2022 at 11:10:00AM -0400, Ross Philipson wrote:
> There are a number of places where early_memremap is called
> but the return pointer is not checked for NULL. The call
> can result in a NULL being returned so the checks must
> be added.
> 
> Signed-off-by: Ross Philipson <ross.philipson@xxxxxxxxxx>
> ---
>  arch/x86/kernel/devicetree.c | 10 ++++++++++
>  arch/x86/kernel/e820.c       |  5 +++++
>  arch/x86/kernel/jailhouse.c  |  6 ++++++
>  arch/x86/kernel/mpparse.c    | 23 +++++++++++++++++++++++
>  arch/x86/kernel/setup.c      |  5 +++++
>  arch/x86/xen/enlighten_hvm.c |  2 ++
>  arch/x86/xen/mmu_pv.c        |  8 ++++++++
>  arch/x86/xen/setup.c         |  2 ++
>  8 files changed, 61 insertions(+)

Ok, a couple of notes:

1. the pr_*("<prefix>:" ... )

thing is done using pr_fmt() - grep the tree for examples.

2. I think you should not panic() the machine but issue a the
warning/error and let the machine die a painful death anyway. But Xen
folks will know better what would be the optimal thing to do.

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette