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From: Peter Zijlstra <peterz@infradead.org>
To: Joe Perches <joe@perches.com>
Cc: Jan Kara <jack@suse.cz>, Steven Rostedt <rostedt@goodmis.org>,
	Markus Trippelsdorf <markus@trippelsdorf.de>,
	Geert Uytterhoeven <geert@linux-m68k.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH] printk: git rid of [sched_delayed] message for printk_deferred
Date: Sat, 20 Sep 2014 20:01:48 +0200	[thread overview]
Message-ID: <20140920180148.GP2832@worktop.localdomain> (raw)
In-Reply-To: <1411229447.24444.53.camel@joe-AO725>

On Sat, Sep 20, 2014 at 09:10:47AM -0700, Joe Perches wrote:
> On Sat, 2014-09-20 at 17:47 +0200, Peter Zijlstra wrote:
> > On a whole, printk() is entirely useless for debugging these days, its
> > far too fragile/unreliable to be taken seriously so I really don't care
> > on that point either.
> 
> That's unfortunate.
> 
> Care to enumerate the issues that you believe make
> printk too fragile/unreliable for debugging?

Look at what it takes to end up at console->write(), and then realize
that some console implementations require scheduling and other nonsense
to actually implement ->write().

The (only) reliable option is early_printk() with the
early_serial_console driver. The rest is useless crap these days.

  parent reply	other threads:[~2014-09-20 18:02 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-14  5:09 Weird character in kernel message Markus Trippelsdorf
2014-09-14  5:54 ` Markus Trippelsdorf
2014-09-14  9:13   ` Geert Uytterhoeven
2014-09-15 16:37     ` Markus Trippelsdorf
2014-09-16 10:55       ` Jan Kara
2014-09-16 14:42         ` [PATCH] printk: git rid of [sched_delayed] message for printk_deferred Markus Trippelsdorf
2014-09-16 15:13           ` Steven Rostedt
2014-09-16 15:20             ` Markus Trippelsdorf
2014-09-16 19:14               ` Steven Rostedt
2014-09-16 19:17                 ` Markus Trippelsdorf
2014-09-16 20:26                   ` Steven Rostedt
2014-09-16 20:35             ` Jan Kara
2014-09-16 21:07               ` Steven Rostedt
2014-09-16 21:22                 ` Jan Kara
2014-09-16 21:33                   ` Steven Rostedt
2014-09-17 14:18                     ` Peter Zijlstra
2014-09-17 14:22                       ` Steven Rostedt
2014-09-17 22:36                         ` Peter Zijlstra
2014-09-18  0:31                           ` Steven Rostedt
2014-09-18 17:34                             ` Peter Zijlstra
2014-09-20  5:12                               ` Jan Kara
2014-09-20 15:32                                 ` Steven Rostedt
2014-09-20 16:34                                   ` Markus Trippelsdorf
2014-09-20 15:47                                 ` Peter Zijlstra
2014-09-20 16:10                                   ` Joe Perches
2014-09-20 16:30                                     ` Steven Rostedt
2014-09-20 18:08                                       ` Peter Zijlstra
2014-09-20 18:01                                     ` Peter Zijlstra [this message]
2014-09-24 11:01                                   ` Jan Kara
2014-09-24 11:11                                     ` [PATCH v2] " Markus Trippelsdorf
2014-09-24 11:26                                       ` Jan Kara
2014-09-24 11:37                                         ` [PATCH v3] " Markus Trippelsdorf
2014-09-24 15:12                                           ` Steven Rostedt
  -- strict thread matches above, loose matches on Subject: below --
2014-09-24 15:20 [PATCH] " Markus Trippelsdorf
2014-09-24 15:35 ` Steven Rostedt

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