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]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1324466604.10752.0.camel@twins \
--to=peterz@infradead.org \
--cc=akpm@linux-foundation.org \
--cc=greg@kroah.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@elte.hu \
--cc=tglx@linutronix.de \
--cc=torvalds@linux-foundation.org \
--cc=tytso@mit.edu \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.