Re: [2.6.18-rc7] printk output delay in syslog wrt dmesg stillunfixed

From: john stultz
Date: Thu Sep 21 2006 - 19:36:02 EST


On Fri, 2006-09-22 at 01:28 +0200, Tilman Schmidt wrote:
> On 19.09.2006 20:52, john stultz wrote:
> > You might try git-bisect to find the offending patch.
>
> This turned out to be easier than I expected.
> The patch which introduces the problem is:
>
> [a0f1ccfd8d37457a6d8a9e01acebeefcdfcc306e] lockdep: do not recurse in printk

When you've narrow down a patch, be sure to CC the author (in this case
Ingo).

> Reverting that patch makes the problem disappear in 2.6.18, too.
> In fact, it suffices to revert just the last chunk:
>
> @@ -809,8 +815,15 @@ void release_console_sem(void)
> console_may_schedule = 0;
> up(&console_sem);
> spin_unlock_irqrestore(&logbuf_lock, flags);
> - if (wake_klogd && !oops_in_progress && waitqueue_active(&log_wait))
> - wake_up_interruptible(&log_wait);
> + if (wake_klogd && !oops_in_progress && waitqueue_active(&log_wait)) {
> + /*
> + * If we printk from within the lock dependency code,
> + * from within the scheduler code, then do not lock
> + * up due to self-recursion:
> + */
> + if (!lockdep_internal())
> + wake_up_interruptible(&log_wait);
> + }
> }
> EXPORT_SYMBOL(release_console_sem);

Ingo, your thoughts?

thanks
-john

-
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