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Date: Tue, 12 Sep 2017 09:42:43 +0900
From: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
To: Petr Mladek <pmladek@suse.com>
Cc: Rob Landley <rob@landley.net>, Michael Ellerman <mpe@ellerman.id.au>,
        Yury Norov <ynorov@caviumnetworks.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Prarit Bhargava <prarit@redhat.com>, Yang Shi <yang.shi@linaro.org>,
        Rasmus Villemoes <linux@rasmusvillemoes.dk>,
        Kees Cook <keescook@chromium.org>, Emese Revfy <re.emese@gmail.com>,
        Fabian Frederick <fabf@skynet.be>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Subject: Re: Patch 0727d35de ("Make initramfs honor CONFIG_DEVTMPFS_MOUNT")
 breaks boot
Message-ID: <20170912004243.GA3963@jagdpanzerIV.localdomain>
References: <20170522120550.ekrq6ipfmkdtlxjo@yury-N73SV>
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 <66dd96ec-b170-0bf6-7746-5466270b3e15@landley.net>
 <87fufta2gi.fsf@concordia.ellerman.id.au>
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On (09/11/17 13:45), Petr Mladek wrote:
[..]
> > Except for the second printk line: If you boot with rdinit=/bin/hush
> > then the first time you mount -t devtmpfs /dev /dev after boot (with
> > CONFIG_DEVTMPFS_MOUNT already having mounted it), you get the 0 return
> > value but the last printk() doesn't output? The second and later times
> > you repeat it, both printk() lines are output.
> > 
> > What's up with printk?
> > 
> > (I added the second printk because the _first_ one wasn't outputting
> > that first time. Something is happening to flush the printk() queue
> > instead of writing it out?
> Maybe, we could setup the timer via an irq_work. We already use
> this trick for flushing deferred printk and waking klogd.
> It is not nice but it would be easier than the previous mess.

printk() and printf() have similar behaviour here. both flush on \n.
so let's keep it the way it is?

	-ss