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From: Petr Mladek <pmladek@suse.com>
To: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Jan Kara <jack@suse.cz>, Tejun Heo <tj@kernel.org>,
	Calvin Owens <calvinowens@fb.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Mel Gorman <mgorman@techsingularity.net>,
	Steven Rostedt <rostedt@goodmis.org>,
	Ingo Molnar <mingo@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Laura Abbott <labbott@redhat.com>,
	Andy Lutomirski <luto@kernel.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Kees Cook <keescook@chromium.org>,
	linux-kernel@vger.kernel.org,
	Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Subject: Re: [RFC][PATCHv4 6/6] printk: remove zap_locks() function
Date: Thu, 1 Dec 2016 14:15:39 +0100	[thread overview]
Message-ID: <20161201131539.GO21230@pathway.suse.cz> (raw)
In-Reply-To: <20161201125045.GA404@tigerII>

On Thu 2016-12-01 21:50:45, Sergey Senozhatsky wrote:
> On (11/25/16 16:01), Petr Mladek wrote:
> [..]
> > > apart from detecting and reporting printk recursions, that code also
> > > used to zap_lockc() in case of panic. However, zap_locks() does not
> >        	          ^
> > 
> > s/zap_lockc/zap_locks/
> > 
> > > look to be needed anymore:
> > > 
> > > 1) Since commit 08d78658f393 ("panic: release stale console lock to
> > >    always get the logbuf printed out") panic flushing of `logbuf' to
> > >    console ignores the state of `console_sem' by doing
> > >    	panic()
> > > 		console_trylock();
> > > 		console_unlock();
> > > 
> > > 2) Since commit cf9b1106c81c ("printk/nmi: flush NMI messages on the
> > >    system panic") panic attempts to zap the `logbuf_lock' spin_lock to
> > >    successfully flush nmi messages to `logbuf'.
> > 
> > Note that the same code is newly used to flush also the printk_safe
> > per-CPU buffers. It means that logbuf_lock is zapped also when
> > flushing these new buffers.
> 
> 
> not quite. there are several checks that would prevent multiple logbuf_lock
> re-inits:

Ah, I did not meant that the lock was zapped twice. I wanted to say
that we added a new path and that it was handled as well :-)

Best Regards,
Petr

  reply	other threads:[~2016-12-01 13:15 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-10-27 15:49 [RFC][PATCHv4 0/6] printk: use printk_safe to handle printk() recursive calls Sergey Senozhatsky
2016-10-27 15:49 ` [RFC][PATCHv4 1/6] printk: use vprintk_func in vprintk() Sergey Senozhatsky
2016-11-24 16:28   ` Petr Mladek
2016-10-27 15:49 ` [RFC][PATCHv4 2/6] printk: rename nmi.c and exported api Sergey Senozhatsky
2016-11-24 16:35   ` Petr Mladek
2016-12-01  1:07     ` Sergey Senozhatsky
2016-12-01 12:12       ` Petr Mladek
2016-10-27 15:49 ` [RFC][PATCHv4 3/6] printk: introduce per-cpu safe_print seq buffer Sergey Senozhatsky
2016-11-24 16:58   ` Petr Mladek
2016-12-01  1:08     ` Sergey Senozhatsky
2016-12-01  5:32     ` Sergey Senozhatsky
2016-10-27 15:49 ` [RFC][PATCHv4 4/6] printk: report lost messages in printk safe/nmi contexts Sergey Senozhatsky
2016-11-25 11:07   ` Petr Mladek
2016-12-01  2:10     ` Sergey Senozhatsky
2016-12-01 12:50       ` Petr Mladek
2016-10-27 15:49 ` [RFC][PATCHv4 5/6] printk: use printk_safe buffers Sergey Senozhatsky
2016-11-25 14:28   ` Petr Mladek
2016-12-01  2:14     ` Sergey Senozhatsky
2016-10-27 15:49 ` [RFC][PATCHv4 6/6] printk: remove zap_locks() function Sergey Senozhatsky
2016-11-25 15:01   ` Petr Mladek
2016-11-25 15:17     ` Peter Zijlstra
2016-12-01  2:34       ` Sergey Senozhatsky
2016-12-01  5:42         ` Peter Zijlstra
2016-12-01 13:36           ` Petr Mladek
2016-12-02  1:11             ` Sergey Senozhatsky
2016-12-01  2:18     ` Sergey Senozhatsky
2016-12-01 12:50     ` Sergey Senozhatsky
2016-12-01 13:15       ` Petr Mladek [this message]
2016-10-28  3:30 ` [RFC][PATCHv4 0/6] printk: use printk_safe to handle printk() recursive calls Linus Torvalds
2016-10-28  4:05   ` Sergey Senozhatsky

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