From: Joe Perches <joe@perches.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Frederic Weisbecker <fweisbec@gmail.com>,
pmladek@suse.cz, Jan Kara <jack@suse.cz>,
Peter Zijlstra <peterz@infradead.org>,
John Stultz <john.stultz@linaro.org>,
Paul Gortmaker <paul.gortmaker@windriver.com>
Subject: Re: [PATCH] printk: Remove separate printk_sched buffers and use printk buf instead
Date: Mon, 05 May 2014 16:33:51 -0700 [thread overview]
Message-ID: <1399332831.27516.6.camel@joe-AO725> (raw)
In-Reply-To: <20140505191846.35aa6f9b@gandalf.local.home>
On Mon, 2014-05-05 at 19:18 -0400, Steven Rostedt wrote:
> To prevent deadlocks with doing a printk inside the scheduler,
> printk_sched() was created. The issue is that printk has a console_sem
> that it can grab and release. The release does a wake up if there's a
> task pending on the sem, and this wake up grabs the rq locks that is
> held in the scheduler. This leads to a possible deadlock if the wake up
> uses the same rq as the one with the rq lock held already.
[]
> kernel/printk/printk.c | 87 +++++++++++++++++++++++++++++++------------------
[]
> @@ -2440,18 +2470,20 @@
> #define PRINTK_BUF_SIZE 512
Wouldn't this define be unused and shouldn't it be deleted too?
next prev parent reply other threads:[~2014-05-05 23:33 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-05 23:18 Steven Rostedt
2014-05-05 23:33 ` Joe Perches [this message]
2014-05-05 23:55 ` Steven Rostedt
2014-05-06 9:45 ` Jan Kara
2014-05-06 11:04 ` Steven Rostedt
2014-05-06 23:37 ` Andrew Morton
2014-05-06 23:46 ` Steven Rostedt
2014-05-07 0:05 ` Steven Rostedt
2014-05-07 14:20 ` Jan Kara
2014-05-07 9:13 ` Petr Mládek
2014-05-07 14:33 ` Jan Kara
2014-05-07 15:57 ` Petr Mládek
2014-05-07 16:29 ` Petr Mládek
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