Re: [PATCH v2 7/9] lib/vsprintf: Replace space with '_' before crng is ready

Petr Mladek
2018-04-11T09:47:19Z

On Fri 2018-02-16 23:07:09, Andy Shevchenko wrote:
> From: Shunyong Yang <shunyong.yang@hxt-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@hxt-semitech.com>
> Suggested-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
> Signed-off-by: Shunyong Yang <shunyong.yang@hxt-semitech.com>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

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

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

Best Regards,
Petr