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From: Viresh Kumar <viresh.kumar@linaro.org>
To: Petr Mladek <pmladek@suse.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>, Jan Kara <jack@suse.cz>,
	Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
	Tejun Heo <tj@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	vlevenetz@mm-sol.com, vaibhav.hiremath@linaro.org,
	alex.elder@linaro.org, johan@kernel.org,
	akpm@linux-foundation.org, rostedt@goodmis.org,
	Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
	Linux PM list <linux-pm@vger.kernel.org>
Subject: Re: [Query] Preemption (hogging) of the work handler
Date: Tue, 12 Jul 2016 07:04:28 -0700	[thread overview]
Message-ID: <20160712140428.GS4695@ubuntu> (raw)
In-Reply-To: <20160712135640.GB8597@pathway.suse.cz>

On 12-07-16, 15:56, Petr Mladek wrote:
> Ah, I have missed that the hang happens only when you use the async
> printk patchset.

And that also doesn't happen always, but only sometimes. So there is a
race somewhere I feel :)

> I wonder if it is somehow related to the commit 8d91f8b15361dfb438ab
> ("printk: do cond_resched() between lines while outputting to
> consoles"). A process (printk thread) might sleep with taken
> console_sem. Then suspend_console() might be unable to
> get the semaphore in console_lock() and might deadlock.

I am not sure at this point really, and I don't have indepth knowledge
of printk core as well (I should accept that here :).

> Does it help to enable "no_console_suspend" please?

No. With no_console_suspend, we just print one more line (Disabling
non-boot CPUs) and once the interrupt on the local CPU are disabled,
we don't get any more prints until a resume happens.

-- 
viresh

  reply	other threads:[~2016-07-12 14:04 UTC|newest]

Thread overview: 56+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-07-01 16:59 [Query] Preemption (hogging) of the work handler Viresh Kumar
2016-07-01 17:22 ` Tejun Heo
2016-07-01 17:28   ` Viresh Kumar
2016-07-06 18:28   ` Viresh Kumar
2016-07-06 19:23     ` Steven Rostedt
2016-07-06 19:25       ` Viresh Kumar
2016-07-11 10:26     ` Jan Kara
2016-07-11 15:44       ` Sergey Senozhatsky
2016-07-11 22:35         ` Viresh Kumar
2016-07-11 22:44           ` Rafael J. Wysocki
2016-07-11 22:46             ` Viresh Kumar
2016-07-12 12:24               ` Rafael J. Wysocki
2016-07-12 13:02                 ` Viresh Kumar
2016-07-12 13:56                   ` Petr Mladek
2016-07-12 14:04                     ` Viresh Kumar [this message]
2016-07-12  9:38           ` Sergey Senozhatsky
2016-07-12 12:52             ` Petr Mladek
2016-07-12 13:12               ` Viresh Kumar
2016-07-12 17:11                 ` Viresh Kumar
2016-07-12 19:59                   ` Rafael J. Wysocki
2016-07-12 20:08                     ` Viresh Kumar
2016-07-13  7:00                   ` Sergey Senozhatsky
2016-07-13 12:05                     ` Rafael J. Wysocki
2016-07-13 12:57                       ` Sergey Senozhatsky
2016-07-13 13:22                         ` Rafael J. Wysocki
2016-07-12 14:03               ` Sergey Senozhatsky
2016-07-12 14:12                 ` Viresh Kumar
2016-07-14 23:52                 ` Viresh Kumar
2016-07-15 13:11                   ` Sergey Senozhatsky
2016-07-15 15:57                     ` Viresh Kumar
2016-07-12 23:19           ` Viresh Kumar
2016-07-13  0:18             ` Viresh Kumar
2016-07-13  5:45             ` Sergey Senozhatsky
2016-07-13 15:39               ` Viresh Kumar
2016-07-13 23:08                 ` Rafael J. Wysocki
2016-07-13 23:18                   ` Viresh Kumar
2016-07-13 23:38                     ` Greg Kroah-Hartman
2016-07-14  0:55                 ` Sergey Senozhatsky
2016-07-14  1:09                   ` Rafael J. Wysocki
2016-07-14  1:32                     ` Sergey Senozhatsky
2016-07-14 21:57                       ` Viresh Kumar
2016-07-14 21:55                   ` Viresh Kumar
2016-07-14 14:12               ` Jan Kara
2016-07-14 14:33                 ` Rafael J. Wysocki
2016-07-14 14:39                   ` Jan Kara
2016-07-14 14:47                     ` Rafael J. Wysocki
2016-07-14 14:55                       ` Jan Kara
2016-07-14 22:14                         ` Viresh Kumar
2016-07-14 14:34                 ` Sergey Senozhatsky
2016-07-14 15:03                   ` Jan Kara
2016-07-14 22:12                 ` Viresh Kumar
2016-07-18 11:01                   ` Jan Kara
2016-07-18 11:49                     ` Rafael J. Wysocki
2016-07-29 20:42               ` Viresh Kumar
2016-07-30  2:12                 ` Sergey Senozhatsky
2016-07-11 19:03       ` Viresh Kumar

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