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From: Ingo Molnar <mingo@elte.hu>
To: Ricky Beam <jfbeam@bluetronic.net>
Cc: Linux Kernel Mail List <linux-kernel@vger.kernel.org>
Subject: Re: overlaping printk
Date: Thu, 20 May 2004 16:03:30 +0200	[thread overview]
Message-ID: <20040520140330.GA1499@elte.hu> (raw)
In-Reply-To: <Pine.GSO.4.33.0405191153500.14297-100000@sweetums.bluetronic.net>


* Ricky Beam <jfbeam@bluetronic.net> wrote:

> It looks like somewhere in the path of release_console_sem() more than
> one CPU is running the log. [...]

the problem is this code in printk:

        if (oops_in_progress) {
                /* If a crash is occurring, make sure we can't deadlock */
                spin_lock_init(&logbuf_lock);
                /* And make sure that we print immediately */
                init_MUTEX(&console_sem);
        }

so two crashes on two separate CPUs can go on in parallel. The problem
is not constrained to the serial line - i've seen it on VGA too (albeit
there it's much more rare).

	Ingo

  reply	other threads:[~2004-05-20 14:01 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-05-19 15:55 overlaping printk Tuukka Toivonen
2004-05-19 16:03 ` Ricky Beam
2004-05-20 14:03   ` Ingo Molnar [this message]
     [not found] <1XBEP-Mc-49@gated-at.bofh.it>
     [not found] ` <1XBXw-13D-3@gated-at.bofh.it>
     [not found]   ` <1XWpp-zy-9@gated-at.bofh.it>
2004-05-20 14:53     ` Andi Kleen
2004-05-20 15:19       ` Ingo Molnar
2004-05-20 15:53         ` Ingo Molnar
2004-05-20 16:19           ` Andy Isaacson
2004-05-20 18:57             ` Ingo Molnar
2004-05-20 23:11               ` Andrew Morton
2004-05-21  7:00                 ` Ingo Molnar
  -- strict thread matches above, loose matches on Subject: below --
2004-05-19 15:19 Ricky Beam
2004-05-19 15:26 ` Tigran Aivazian
2004-05-19 15:31   ` Ricky Beam
2004-05-19 15:39 ` Randy.Dunlap
2004-05-20  7:21 ` Andrew Morton

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