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From: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
To: Petr Mladek <pmladek@suse.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
	Maninder Singh <maninder1.s@samsung.com>,
	sergey.senozhatsky@gmail.com, rostedt@goodmis.org,
	linux-kernel@vger.kernel.org, a.sahrawat@samsung.com,
	pankaj.m@samsung.com, v.narang@samsung.com
Subject: Re: [PATCH 2/2] printk: make sure to print log on console.
Date: Fri, 1 Jun 2018 18:37:38 +0900	[thread overview]
Message-ID: <20180601093738.GC1841@jagdpanzerIV> (raw)
In-Reply-To: <20180601090942.ek3j4bpbhschljrw@pathway.suse.cz>

On (06/01/18 11:09), Petr Mladek wrote:
> > [...]
> > 
> > > So I'd say that most likely the following scenarios can suffer:
> > > 
> > > - NMI comes in, sets loglevel to X, printk-s some data, restores the
> > >   loglevel back to Y
> > > - IRQ comes in [like sysrq, etc] comes in and does the same thing
> > > - software exception comes in and does the same thing [e.g. bust_spinlocks()
> > >   at arch/s390/mm/fault.c]
> 
> I forgot to say that it was a great point and analyze.

Thanks :)

> > My view is:
> > 
> > The race with another printk() (console_lock owner) is much more
> > likely than a race between two CPUs manipulating console_loglevel.
> > 
> > The proposed patch seems to be in the right direction. It is supposed
> > to fix the most likely scenario. We could block it and request full
> > solution but I wonder if it is worth it.
> > 
> > I am personally fine with this partial solution for now. We could
> > always make it better if people meet the other scenarios.
> 
> I am still fine with the partial solution. Well, I will think
> more about it before approving any patch.

Same here. I don't mind the patch and can agree with this partial
solution [may be we are missing more cases?]. Probably will need
a little bit more time.

	-ss

  reply	other threads:[~2018-06-01  9:37 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CGME20180531102246epcas5p2f1cbc6ff217172e12e2f78bb88eb4a7e@epcas5p2.samsung.com>
2018-05-31 10:19 ` Maninder Singh
2018-05-31 10:52   ` Sergey Senozhatsky
2018-05-31 12:21     ` Petr Mladek
2018-06-01  4:40       ` Sergey Senozhatsky
2018-06-01  8:53         ` Petr Mladek
2018-06-01  9:09           ` Petr Mladek
2018-06-01  9:37             ` Sergey Senozhatsky [this message]
2018-06-01  9:18           ` Sergey Senozhatsky
     [not found]       ` <CGME20180531102246epcas5p2f1cbc6ff217172e12e2f78bb88eb4a7e@epcms5p5>
2018-06-01  8:42         ` Vaneet Narang
2018-06-01  9:34           ` Sergey Senozhatsky
2018-05-31 13:27   ` Petr Mladek

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