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From: Petr Mladek <pmladek@suse.com>
To: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Dmitry Safonov <dima@arista.com>,
	linux-kernel@vger.kernel.org,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Jiri Slaby <jslaby@suse.com>,
	Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Subject: Re: [RFC] printk/sysrq: Don't play with console_loglevel
Date: Wed, 12 Jun 2019 14:00:12 +0200	[thread overview]
Message-ID: <20190612120012.mmokgz4yybywfs26@pathway.suse.cz> (raw)
In-Reply-To: <20190612083643.GA7722@jagdpanzerIV>

On Wed 2019-06-12 17:36:43, Sergey Senozhatsky wrote:
> On (06/06/19 09:10), Petr Mladek wrote:
> > Just to be sure. I wanted to say that I like the idea with
> > KERN_UNSUPRESSED. So, I think that we are on the same page.
> 
> I understand. All I wanted to say is that KERN_UNSUPRESSED is
> per-message, while the most interesting (and actually broken)
> cases, IMHO, are per-context, IOW things like this one
> 
> 	console_loglevel = NEW
> 	foo()
> 	  dump_stack()
> 	     printk
> 	     ...
> 	     printk
> 	console_loglevel = OLD
> 
> KERN_UNSUPRESSED does not help here. We probably can't convert
> dump_stack() to KERN_UNSUPRESSED.

I agree. I take KERN_UNSUPRESSED like a nice trick how to pass
the information about the unsupressed printk context via
printk_safe and printk_nmi per-CPU buffers.

The single line in sysrq __handle_sysrq() seems to be the only
location where KERN_UNSUPRESSED can be used directly.

Best Regards,
Petr

  reply	other threads:[~2019-06-12 12:00 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-28  0:24 [RFC] printk/sysrq: Don't play with console_loglevel Dmitry Safonov
2019-05-28  3:21 ` Tetsuo Handa
2019-05-28  4:22   ` Sergey Senozhatsky
2019-05-28  8:02     ` Tetsuo Handa
2019-05-28  8:51       ` Sergey Senozhatsky
2019-05-28 10:15         ` Tetsuo Handa
2019-05-28 13:49           ` Petr Mladek
2019-06-07 17:09           ` Pavel Machek
2019-06-08  2:45             ` Tetsuo Handa
2019-06-11 15:10               ` Petr Mladek
2019-06-12 10:06                 ` Tetsuo Handa
2019-05-28  4:15 ` Sergey Senozhatsky
2019-05-28  4:46   ` Sergey Senozhatsky
2019-05-28 13:42     ` Petr Mladek
2019-05-28 14:21       ` Tetsuo Handa
2019-05-28 15:03         ` Petr Mladek
2019-05-28 15:21           ` Tetsuo Handa
2019-05-28 15:58             ` Dmitry Safonov
2019-05-31 14:11       ` Tetsuo Handa
2019-06-02  6:13         ` [RFC] printk: Introduce per context console loglevel Tetsuo Handa
2019-06-06  7:59           ` Petr Mladek
2019-06-03  6:51       ` [RFC] printk/sysrq: Don't play with console_loglevel Sergey Senozhatsky
2019-06-06  7:10         ` Petr Mladek
2019-06-12  8:36           ` Sergey Senozhatsky
2019-06-12 12:00             ` Petr Mladek [this message]
2019-06-12 14:47               ` Dmitry Safonov

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