From mboxrd@z Thu Jan  1 00:00:00 1970
From: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Subject: Re: [RFC][PATCH 0/6] Use printk_safe context for TTY and UART port
 locks
Date: Wed, 20 Jun 2018 11:56:41 +0900
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To: Steven Rostedt <rostedt@goodmis.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>, Petr Mladek <pmladek@suse.com>, Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>, One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Jiri Slaby <jslaby@suse.com>, Peter Zijlstra <peterz@infradead.org>, Andrew Morton <akpm@linux-foundation.org>, Dmitry Vyukov <dvyukov@google.com>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, linux-serial <linux-serial@vger.kernel.org>, SergeySenozhatsky <sergey.senozhatsky@gmail.com>
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On (06/19/18 22:34), Steven Rostedt wrote:
> 
> > There is no valid reason why an UART driver should do a printk() of
> > any sort inside the critical region where the console is locked.
> > 
> > Just remove those printk's, don't add new crazy locking.
> 
> Perhaps we should do an audit of the console drivers and remove all
> printk, pr_* , WARN*, BUG* from them.

I think I did a terrible job explaining my motivation.

Sorry for that!


What I tried to address with my patch set was not a direct uart->printk,
but mostly all those

        uart-> tty / core kernel / who knows what else -> printk

cases. When are in that special context "called from uart driver" which
can backfire on us.

	-ss