From: Tejun Heo <tj@kernel.org>
To: Christoph Lameter <cl@linux-foundation.org>
Cc: Tony Vroon <tony@linx.net>,
Linux Kernel <linux-kernel@vger.kernel.org>,
Rusty Russell <rusty@rustcorp.com.au>,
Ingo Molnar <mingo@elte.hu>, "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH] percpu: fix unit_map[] verification in pcpu_setup_first_chunk()
Date: Tue, 29 Sep 2009 01:35:36 +0900 [thread overview]
Message-ID: <4AC0E5D8.6090707@kernel.org> (raw)
In-Reply-To: <alpine.DEB.1.10.0909281223510.16040@gentwo.org>
Christoph Lameter wrote:
> On Tue, 29 Sep 2009, Tejun Heo wrote:
>
>> pcpu_setup_first_chunk() incorrectly used NR_CPUS as the impossible
>> unit number while unit number can equal and go over NR_CPUS with
>> sparse unit map. This triggers BUG_ON() spuriously on machines which
>> have non-power-of-two number of cpus. Use UINT_MAX instead.
>
> Uhhh. Funky. The assumption nr_cpu_ids < NR_CPUS has been broken. Wonder
> what other effects that will have. In particular since the slab and page
> allocators have arrays indexed by the cpu number and those arrays are
> dimensioned for NR_CPUS.
Heh.. that's not what's broken. unit# can legally go over NR_CPUS or
nr_cpu_ids as cpus can be sparsely mapped to units. The problem is
that I didn't fix unit_map allocation. Will update the patch. Just a
sec.
--
tejun
next prev parent reply other threads:[~2009-09-28 16:36 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-09-24 0:53 [PATCH] percpu: make pcpu_setup_first_chunk() failures more verbose Tejun Heo
2009-09-24 12:49 ` [PATCH] percpu: make allocation " Tejun Heo
2009-09-27 12:49 ` 2.6.31-09194-g0d9df25 Early boot exception Tony Vroon
2009-09-28 16:19 ` [PATCH] percpu: fix unit_map[] verification in pcpu_setup_first_chunk() Tejun Heo
2009-09-28 16:25 ` Christoph Lameter
2009-09-28 16:35 ` Tejun Heo [this message]
2009-09-28 16:38 ` Tejun Heo
2009-09-28 16:40 ` Christoph Lameter
2009-09-28 16:53 ` Tejun Heo
2009-09-28 22:07 ` Tony Vroon
2009-09-29 0:15 ` Tejun Heo
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=4AC0E5D8.6090707@kernel.org \
--to=tj@kernel.org \
--cc=cl@linux-foundation.org \
--cc=hpa@zytor.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@elte.hu \
--cc=rusty@rustcorp.com.au \
--cc=tony@linx.net \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.