linux-kernel - Re: [PATCH v2 7/9] lib/vsprintf: Replace space with '

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Date:   Wed, 11 Apr 2018 11:47:12 +0200
From:   Petr Mladek <pmladek@...e.com>
To:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc:     "Tobin C . Harding" <me@...in.cc>, linux@...musvillemoes.dk,
        Joe Perches <joe@...ches.com>, linux-kernel@...r.kernel.org,
        Andrew Morton <akpm@...ux-foundation.org>,
        Shunyong Yang <shunyong.yang@...-semitech.com>,
        Joey Zheng <yu.zheng@...-semitech.com>
Subject: Re: [PATCH v2 7/9] lib/vsprintf: Replace space with '_' before crng
 is ready

On Fri 2018-02-16 23:07:09, Andy Shevchenko wrote:
> From: Shunyong Yang <shunyong.yang@...-semitech.com>
> 
> Before crng is ready, output of "%p" composes of "(ptrval)" and
> left padding spaces for alignment as no random address can be
> generated. This seems a little strange when default string width
> is larger than strlen("(ptrval)").
> 
> For example, when irq domain names are built with "%p", the nodes
> under /sys/kernel/debug/irq/domains like this on AArch64 system,
> 
> [root@y irq]# ls domains/
> default                   irqchip@        (ptrval)-2
> irqchip@        (ptrval)-4  \_SB_.TCS0.QIC1  \_SB_.TCS0.QIC3
> irqchip@        (ptrval)  irqchip@        (ptrval)-3
> \_SB_.TCS0.QIC0             \_SB_.TCS0.QIC2
> 
> The name "irqchip@        (ptrval)-2" is not so readable in console
> output.
> 
> This patch replaces space with readable "_" when output needs padding.
> Following is the output after applying the patch,
> 
> [root@y domains]# ls
> default                   irqchip@(____ptrval____)-2
> irqchip@(____ptrval____)-4  \_SB_.TCS0.QIC1  \_SB_.TCS0.QIC3
> irqchip@(____ptrval____)  irqchip@(____ptrval____)-3  \_SB_.TCS0.QIC0
> \_SB_.TCS0.QIC2
> 
> There is same problem in some subsystem's dmesg output. Moreover,
> someone may call "%p" in a similar case. In addition, the timing of
> crng initialization done may vary on different system. So, the change
> is made in vsprintf.c.
> 
> Cc: Joey Zheng <yu.zheng@...-semitech.com>
> Suggested-by: Rasmus Villemoes <linux@...musvillemoes.dk>
> Signed-off-by: Shunyong Yang <shunyong.yang@...-semitech.com>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>

Reviewed-by: Petr Mladek <pmladek@...e.com>

I have pushed it into printk.git, branch for-4.18-vsprintf-cleanup.

Best Regards,
Petr