From: Ingo Molnar <mingo@elte.hu>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: john stultz <johnstul@us.ibm.com>,
Thomas Gleixner <tglx@linutronix.de>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH RT] don't let printk unconditionally turn on interrupts
Date: Sat, 21 Jan 2006 11:28:08 +0100 [thread overview]
Message-ID: <20060121102808.GB991@elte.hu> (raw)
In-Reply-To: <1137811001.6762.179.camel@localhost.localdomain>
* Steven Rostedt <rostedt@goodmis.org> wrote:
> Ingo,
>
> My first try at booting -rt8 on my machine crashed immediately. No
> nmi, no nothing. Just a lockup at the registration of the ACPI_PM
> timer. This would happen every time, and after struggling for a while,
> I finally found out why!
>
> The printk in timeofday_periodic_hook that is called holding the
> write_lock of system_time_lock (a raw_seq_lock) was causing lots of
> havoc. The printk would turn on interrupts, and then I would get a
> deadlock when the interrupt would do a read on system_time_lock.
argh. This piece of code has caused so many problems already. Some
people want console drivers to be preemptible, but i guess being able to
boot trumps things ;)
could you check out the variant in 2.6.15-rt11 - i tweaked it slightly
over yours, hopefully making the behavior more consistent.
Ingo
next prev parent reply other threads:[~2006-01-21 10:27 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-01-21 2:36 Steven Rostedt
2006-01-21 10:28 ` Ingo Molnar [this message]
2006-01-21 12:07 ` Steven Rostedt
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