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Date: Thu, 2 Feb 2017 16:37:54 +0100
From: Petr Mladek <pmladek@suse.com>
To: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>,
        Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Jan Kara <jack@suse.cz>, Tejun Heo <tj@kernel.org>,
        Calvin Owens <calvinowens@fb.com>, Ingo Molnar <mingo@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Andy Lutomirski <luto@kernel.org>,
        Peter Hurley <peter@hurleysoftware.com>, linux-kernel@vger.kernel.org
Subject: Re: [PATCHv7 4/8] printk: always use deferred printk when flush
 printk_safe lines
Message-ID: <20170202153753.GF23754@pathway.suse.cz>
References: <20161227141611.940-1-sergey.senozhatsky@gmail.com>
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 <20170201110648.33651ee8@gandalf.local.home>
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On Thu 2017-02-02 15:05:38, Sergey Senozhatsky wrote:
> On (02/01/17 11:06), Steven Rostedt wrote:
> [..]
> > >  static void printk_safe_flush_line(const char *text, int len)
> > >  {
> > >  	/*
> > > -	 * The buffers are flushed in NMI only on panic.  The messages must
> > > -	 * go only into the ring buffer at this stage.  Consoles will get
> > > -	 * explicitly called later when a crashdump is not generated.
> > > +	 * Avoid any console drivers calls from here, because we may be
> > > +	 * in NMI or printk_safe context (when in panic). The messages
> > > +	 * must go only into the ring buffer at this stage.  Consoles will
> > > +	 * get explicitly called later when a crashdump is not generated.
> > >  	 */
> > > -	if (in_nmi())
> > > -		printk_deferred("%.*s", len, text);
> > > -	else
> > > -		printk("%.*s", len, text);
> > > +	printk_deferred("%.*s", len, text);
> > >  }
> > 
> > The helper function was there because of the if statement. Just nuke
> > this function and call printk_deferred() directly. You can move the
> > comment to the caller.
> 
> indeed. thanks.
> 
> Petr, how would you prefer to handle this?

I am still learning how to manage the patches in the printk.git tree.

I would like to add Steven's Reviewed-by tags, links to the mails,
and list of CC-ed people. IMHO, the only way is to rebase the for-4.11
and for-next branches. Then I could do the above suggested change during
the rebase.

Any other solutions are welcome. I will wait with the rebase at least
until Monday. We are discussing the lockdep in the 6th patch anyway.

Best Regards,
Petr