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From: Steven Rostedt <rostedt@goodmis.org>
To: Petr Mladek <pmladek@suse.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
	akpm@linux-foundation.org, linux-mm@kvack.org,
	Peter Zijlstra <peterz@infradead.org>, Jan Kara <jack@suse.cz>,
	Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
	Tejun Heo <tj@kernel.org>,
	linux-kernel@vger.kernel.org,
	Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Subject: Re: [PATCH] printk: Ratelimit messages printed by console drivers
Date: Fri, 20 Apr 2018 11:13:07 -0400	[thread overview]
Message-ID: <20180420111307.44008fc7@gandalf.local.home> (raw)
In-Reply-To: <20180420145720.hb7bbyd5xbm5je32@pathway.suse.cz>

On Fri, 20 Apr 2018 16:57:20 +0200
Petr Mladek <pmladek@suse.com> wrote:


> No, call_console_drivers() is done with interrupts disabled:
> 
> 		console_lock_spinning_enable();
> 
> 		stop_critical_timings();	/* don't trace print latency */
>  ---->		call_console_drivers(ext_text, ext_len, text, len);  
> 		start_critical_timings();
> 
> 		if (console_lock_spinning_disable_and_check()) {
>  ---->			printk_safe_exit_irqrestore(flags);  
> 			goto out;
> 		}
> 
>  ---->		printk_safe_exit_irqrestore(flags);  
> 
> They were called with interrupts disabled for ages, long before
> printk_safe. In fact, it was all the time in the git kernel history.
> 
> Therefore only NMIs are in the game. And they should be solved
> by the above change.
> 

Really?


  console_trylock_spinning(); /* console_owner now equals current */
  console_unlock() {

---> take interrupt here:

					vprintk() {
					   vprintk_func() {
					      if (console_owner == current && !__ratelimit(&ratelimit_console))

				[ RATE LIMIT HERE!!!! ]


	for (;;) {
		printk_safe_enter_irqsave(flags);

-- Steve

  reply	other threads:[~2018-04-20 15:13 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-13 12:47 Petr Mladek
2018-04-13 14:12 ` Steven Rostedt
2018-04-14  2:35   ` Sergey Senozhatsky
2018-04-16  1:47     ` Sergey Senozhatsky
2018-04-16  4:25       ` Sergey Senozhatsky
2018-04-19 12:53         ` Petr Mladek
2018-04-20  2:15           ` Sergey Senozhatsky
2018-04-20  9:12             ` Petr Mladek
2018-04-20 12:04               ` Steven Rostedt
2018-04-20 14:01                 ` Petr Mladek
2018-04-20 14:17                   ` Steven Rostedt
2018-04-20 14:19                     ` Steven Rostedt
2018-04-20 14:57                     ` Petr Mladek
2018-04-20 15:13                       ` Steven Rostedt [this message]
2018-04-23 10:32                         ` Petr Mladek
2018-04-23 11:36                           ` Steven Rostedt
2018-04-23 12:45                             ` Petr Mladek
2018-04-25  5:31                               ` Sergey Senozhatsky
2018-04-26  9:42                                 ` Petr Mladek
2018-04-27 10:22                                   ` Sergey Senozhatsky
2018-05-09 12:00                                     ` Petr Mladek
2018-05-09 12:59                                       ` Steven Rostedt
2019-02-26 10:24                                       ` Tetsuo Handa
2019-02-28  4:45                                         ` Sergey Senozhatsky
2018-04-23  5:21               ` Sergey Senozhatsky
2018-04-23 12:26                 ` Petr Mladek
2018-04-23 13:00                   ` Sergey Senozhatsky

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