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From: walter harms <wharms@bfs.de>
To: Andi Kleen <ak@linux.intel.com>
Cc: Vasiliy Kulikov <segooon@gmail.com>,
	kernel-janitors@vger.kernel.org,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
	x86@kernel.org, Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>,
	Borislav Petkov <borislav.petkov@amd.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 04/10] x86: mce: fix error handling
Date: Thu, 29 Jul 2010 10:10:20 +0000	[thread overview]
Message-ID: <4C51538C.1090803@bfs.de> (raw)
In-Reply-To: <4C514F04.80603@linux.intel.com>



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


  reply	other threads:[~2010-07-29 10:10 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-07-28 16:39 [PATCH 04/10] x86: mce: fix error handling Kulikov Vasiliy
2010-07-28 16:48 ` Borislav Petkov
2010-07-28 17:07 ` Andi Kleen
2010-07-28 17:13   ` Vasiliy Kulikov
2010-07-28 17:20     ` Andi Kleen
2010-07-29  9:35       ` Vasiliy Kulikov
2010-07-29  9:51         ` Andi Kleen
2010-07-29 10:10           ` walter harms [this message]
2010-07-31 18:18             ` Vasiliy Kulikov
2010-07-31 19:07             ` Vasiliy Kulikov
2010-07-29 10:16           ` Borislav Petkov

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