From: ebiederm@xmission.com (Eric W. Biederman)
To: Andi Kleen <ak@suse.de>
Cc: Fernando Luis Vazquez Cao <fernando@intellilink.co.jp>,
fastboot@lists.osdl.org, linux-kernel@vger.kernel.org
Subject: Re: [Fastboot] Re: [PATCH 1/4] stack overflow safe kdump (i386) - safe_smp_processor_id
Date: Mon, 28 Nov 2005 21:16:20 -0700 [thread overview]
Message-ID: <m1d5kkf5rf.fsf@ebiederm.dsl.xmission.com> (raw)
In-Reply-To: <p738xv8id6r.fsf@verdi.suse.de> (Andi Kleen's message of "28 Nov 2005 16:07:40 -0700")
Andi Kleen <ak@suse.de> writes:
> Fernando Luis Vazquez Cao <fernando@intellilink.co.jp> writes:
>>
>> To circumvent this problem I suggest implementing
>> "safe_smp_processor_id()" (it already exists on x86_64) for i386 and
>> IA64 and use it as a replacement to smp_processor_id in the reboot path
>> to the dump capture kernel. This is a possible implementation for i386.
>
> It's not fully safe, because a SMP kernel might run on a 32bit
> system without APIC. Then hard_smp_processor_id() would fault.
> (this cannot happen on x86-64)
>
> You probably need to check one of the globals set by apic.c
> when its disabled.
Right. An SMP kernel on a uniprocessor, without apics.
To my knowledge all SMP systems that linux supports have
apics.
Eric
next prev parent reply other threads:[~2005-11-29 4:17 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-11-28 18:00 [PATCH 1/4] stack overflow safe kdump (i386) - safe_smp_processor_id Fernando Luis Vazquez Cao
2005-11-28 23:07 ` Andi Kleen
2005-11-29 4:16 ` Eric W. Biederman [this message]
2005-11-30 7:32 ` [Fastboot] " Fernando Luis Vazquez Cao
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