mirror of https://lore.kernel.org/lkml/
 help / color / mirror / Atom feed
From: Russell King - ARM Linux <linux@arm.linux.org.uk>
To: Stephen Boyd <sboyd@codeaurora.org>
Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC/PATCH] ARM: smp: Fix cpu_up() racing with sys_reboot
Date: Thu, 30 Aug 2012 00:53:53 +0100	[thread overview]
Message-ID: <20120829235353.GW18957@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <1345608229-5707-1-git-send-email-sboyd@codeaurora.org>

On Tue, Aug 21, 2012 at 09:03:49PM -0700, Stephen Boyd wrote:
> Nothing stops a process from hotplugging in a CPU concurrently
> with a sys_reboot() call. In such a situation we could have
> ipi_cpu_stop() mark a cpu as 'offline' and _cpu_up() ignore the
> fact that the CPU is not really offline and call the
> CPU_UP_PREPARE notifier. When this happens stop_machine code will
> complain that the cpu thread already exists and BUG_ON().

This puts us at odds with x86, which is a bad thing without first
investigating whether a generic solution which fixes all arches would
be more appropriate.

A better solution may be to mark those CPUs as being not-present,
which will prevent them being hot-plugged back.

  parent reply	other threads:[~2012-08-29 23:54 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-08-22  4:03 Stephen Boyd
2012-08-29  7:24 ` Stephen Boyd
2012-08-29 23:53 ` Russell King - ARM Linux [this message]
2012-08-30 19:00   ` Stephen Boyd

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=20120829235353.GW18957@n2100.arm.linux.org.uk \
    --to=linux@arm.linux.org.uk \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=sboyd@codeaurora.org \
    /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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
Powered by JetHome