From: Peter Zijlstra <peterz@infradead.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "Ted Ts'o" <tytso@mit.edu>, Greg KH <greg@kroah.com>,
Ingo Molnar <mingo@elte.hu>, Thomas Gleixner <tglx@linutronix.de>,
akpm@linux-foundation.org,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [RFC][PATCH 0/7] improve printk reliability
Date: Wed, 21 Dec 2011 12:23:24 +0100 [thread overview]
Message-ID: <1324466604.10752.0.camel@twins> (raw)
In-Reply-To: <20111221105739.798864333@chello.nl>
On Wed, 2011-12-21 at 11:57 +0100, Peter Zijlstra wrote:
> Hi,
>
> So these are my current efforts to make my own console output more
> reliable. I've hit every deadlock described in this series and a few
> more.
>
> With these patches applied I can printk() and WARN() from inside
> scheduler context and not have my machine deadlock, even without the
> aid of early_printk().
>
> While I'll go an remove the sole printk() I found in the scheduler
> so that we don't have to rely on the console doing this, it is good
> to have a reliable console that can do this.
>
> As it stands some of the patches, the semaphore one in particular,
> are really too ugly to live so I won't push those but wanted to share
> anyway.
>
> Debugging this was 'fun', and I really hope to not have to do it
> again :-)
Also, these patches enable lockdep over printk(), allowing lockdep to
detect previously undetected deadlocks with console implementations,
irrespective of rq->lock.
prev parent reply other threads:[~2011-12-21 11:23 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-21 10:57 [RFC][PATCH 0/7] improve printk reliability Peter Zijlstra
2011-12-21 10:57 ` [RFC][PATCH 1/7] arch, early_printk: Consolidate early_printk() implementations Peter Zijlstra
2011-12-21 17:01 ` Mike Frysinger
2011-12-21 17:03 ` Peter Zijlstra
2011-12-21 19:23 ` David Miller
2011-12-21 10:57 ` [RFC][PATCH 2/7] lockdep: Provide early_printk() support Peter Zijlstra
2011-12-21 10:57 ` [RFC][PATCH 3/7] printk, lockdep: Remove lockdep_off() usage Peter Zijlstra
2011-12-21 10:57 ` [RFC][PATCH 4/7] printk: Rework printk recursion Peter Zijlstra
2011-12-21 10:57 ` [RFC][PATCH 5/7] semaphore: Pull wakeup out from under sem->lock Peter Zijlstra
2011-12-21 10:57 ` [RFC][PATCH 6/7] printk: Poke printk extra hard Peter Zijlstra
2011-12-22 1:17 ` Linus Torvalds
2011-12-22 7:02 ` Ingo Molnar
2011-12-22 8:43 ` Peter Zijlstra
2011-12-22 9:03 ` Ingo Molnar
2011-12-22 9:14 ` Peter Zijlstra
2011-12-22 10:15 ` Ingo Molnar
2011-12-22 10:19 ` Peter Zijlstra
2011-12-21 10:57 ` [RFC][PATCH 7/7] serial, 8250: Mostly avoid wakeups from under port->lock Peter Zijlstra
2011-12-21 16:03 ` Alan Cox
2011-12-21 16:22 ` Peter Zijlstra
2011-12-21 16:30 ` Peter Zijlstra
2011-12-21 18:51 ` Alan Cox
2011-12-21 11:23 ` Peter Zijlstra [this message]
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