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From: Rusty Russell <rusty@rustcorp.com.au>
To: "Vegard Nossum" <vegard.nossum@gmail.com>
Cc: "Adrian Bunk" <bunk@kernel.org>,
	"Srivatsa Vaddagiri" <vatsa@in.ibm.com>,
	"Mike Travis" <travis@sgi.com>,
	linux-kernel@vger.kernel.org, "Gautham R Shenoy" <ego@in.ibm.com>,
	"Rafael J. Wysocki" <rjw@sisk.pl>,
	"Zhang, Yanmin" <yanmin.zhang@intel.com>,
	"Heiko Carstens" <heiko.carstens@de.ibm.com>
Subject: Re: v2.6.26-rc7: BUG: unable to handle kernel NULL pointer dereference
Date: Mon, 23 Jun 2008 13:26:10 +1000	[thread overview]
Message-ID: <200806231326.11328.rusty@rustcorp.com.au> (raw)
In-Reply-To: <19f34abd0806220929y1ca9d0c4nbf480473b7ce018a@mail.gmail.com>

On Monday 23 June 2008 02:29:07 Vegard Nossum wrote:
> And the (cpu < nr_cpu_ids) fails because the CPU has just been
> offlined (or failed to initialize, but it's the same thing), while
> NR_CPUS is the value that was compiled in as CONFIG_NR_CPUS (so the
> former check will always be true).
>
> I don't think it is valid to ask for a per_cpu() variable on a CPU
> which does not exist, though

Yes it is.  As long as cpu_possible(cpu), per_cpu(cpu) is valid.

The number check should be removed: checking cpu_possible() is sufficient.

Hope that helps,
Rusty.

  reply	other threads:[~2008-06-23  3:28 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-06-22 12:56 v2.6.26-rc7: BUG: unable to handle kernel NULL pointer dereference Vegard Nossum
2008-06-22 14:47 ` Vegard Nossum
2008-06-22 14:54   ` Vegard Nossum
2008-06-22 15:56     ` Adrian Bunk
2008-06-22 16:29       ` Vegard Nossum
2008-06-23  3:26         ` Rusty Russell [this message]
2008-06-23 16:58           ` Mike Travis
2008-06-24  1:36             ` Rusty Russell
2008-06-24  7:40               ` Vegard Nossum
2008-06-24  8:06               ` Zhang, Yanmin
2008-06-24  8:37                 ` Vegard Nossum
2008-06-24 13:14                 ` Rusty Russell
2008-06-24 14:44                   ` Mike Travis
2008-06-25  5:38                     ` Rusty Russell
2008-06-25 15:06                       ` Mike Travis
2008-06-26 12:58                   ` Gautham R Shenoy
2008-06-27  3:16                     ` Rusty Russell
2008-06-30 11:19                   ` Ingo Molnar
2008-06-26  0:59                 ` Zhang, Yanmin
2008-06-26  2:15                   ` Andrew Morton
2008-06-26  9:00                     ` Vegard Nossum
2008-06-26 12:40                       ` Jason Wessel
2008-06-26 13:59                         ` Vegard Nossum
2008-07-10 19:10                 ` Vegard Nossum

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