Re: overlaping printk

From: Ingo Molnar (mingo_at_elte.hu)
Date: 05/20/04

  • Next message: Bartlomiej Zolnierkiewicz: "Re: protecting source code in 2.6" 
    Date:	Thu, 20 May 2004 16:03:30 +0200
To: Ricky Beam <jfbeam@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
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  • Next message: Bartlomiej Zolnierkiewicz: "Re: protecting source code in 2.6"

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