linux-kernel - Re: [PATCH v2 0/3] printk: Deadlock in NMI regression

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Message-ID: <20180627143419.r75lat5cwzw3hns2@pathway.suse.cz>
Date:   Wed, 27 Jun 2018 16:34:19 +0200
From:   Petr Mladek <pmladek@...e.com>
To:     Sergey Senozhatsky <sergey.senozhatsky@...il.com>
Cc:     Steven Rostedt <rostedt@...dmis.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>,
        Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>,
        linux-kernel@...r.kernel.org, stable@...r.kernel.org
Subject: Re: [PATCH v2 0/3] printk: Deadlock in NMI regression

On Wed 2018-06-27 23:16:12, Sergey Senozhatsky wrote:
> On (06/27/18 16:08), Petr Mladek wrote:
> > The commit 719f6a7040f1bdaf96 ("printk: Use the main logbuf in NMI
> > when logbuf_lock is available") brought back the possible deadlocks
> > in printk() and NMI.
> > 
> > This is rework of the proposed fix, see
> > https://lkml.kernel.org/r/20180606111557.xzs6l3lkvg7lq3ts@pathway.suse.cz

Grr, the right link is
https://lkml.kernel.org/r/20180608104825.e7xoxteelaxnwx66@pathway.suse.cz


> > I realized that we could rather easily move the check to vprintk_func()
> > and still avoid any race. I believe that this is a win-win solution.
> > 
> > 
> > Changes against v1:
> > 
> >   + Move the check from vprintk_emit() to vprintk_func()
> >   + More straightforward commit message
> >   + Fix build with CONFIG_PRINTK_NMI disabled
> 
> Did I miss out V1?

It is the above fixed link. I am sorry for the confusion.


> > Petr Mladek (3):
> >   printk: Split the code for storing a message into the log buffer
> >   printk: Create helper function to queue deferred console handling
> >   printk/nmi: Prevent deadlock when accessing the main log buffer in NMI
> 
> Patch 3/3 is not in my mailbox, somehow [I checked the spam folder].
> I'm not Cc-ed or the message got lost somewhere before it reached my
> gmail?

Ah, the following line somehow confused git send-mail and the message
had broken list of recipients:

Cc: stable@...r.kernel.org # 4.13+

I have sent it once again as you have already noticed.

Best Regards,
Petr