Re: [PATCH 04/10] x86: mce: fix error handling

From: walter harms
Date: Thu Jul 29 2010 - 06:10:34 EST




Andi Kleen schrieb:
>
>> IMO memmory allocation fails are dangerous in kernel mode. As it is
>> probably not exploitable because of boot time, it can destroy some
>> sensitive data like dirty disk caches those are going to be written on
>> disk.
>
> It's true for runtime, but not for normal boot time.
>
> Anyways if it happens on boot time the only thing you can do is panic,
> but someone else
> will likely panic anyways for you. Just ignoring it like your patch
> effectively does
> (because nothing will ever look at the ENOMEMs for an initcall) is wrong
> though
> In this case it's actually better to oops like the original code does.
>
> BTW even with your patch likely later code will crash anyways because it
> doesn't
> expect init code to fail.
>

NTL it is nice to have a error message. for users it is worse if you crash suddenly
with out warning than having a crash with "OOM" before because it gives you a clue
what is going on.
short:
please think of users that are not kernel developers give them a hint what went wrong.

to make thinks more easy on boot we could replace kalloc() with kmalloc_or_die().
When anyone runs out of mem on boottime you can panic() instantly.

just my to cents,
wh

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