linux-kernel - Re: [PATCH v2] console: console: Complete exception handling in newport

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Message-ID: <081f8192-1708-80ff-6eef-885d72bdf5c5@samsung.com>
Date:   Thu, 23 Apr 2020 16:55:35 +0200
From:   Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
To:     Dejin Zheng <zhengdejin5@...il.com>
Cc:     gregkh@...uxfoundation.org, tglx@...utronix.de,
        FlorianSchandinat@....de, ralf@...ux-mips.org,
        tsbogend@...ha.franken.de, dri-devel@...ts.freedesktop.org,
        linux-fbdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        Andy Shevchenko <andy.shevchenko@...il.com>
Subject: Re: [PATCH v2] console: console: Complete exception handling in
 newport_probe()


Hi,

I believe that the patch summary line should be:

"[PATCH v2] console: newport_con: ..."

On 4/23/20 4:26 PM, Dejin Zheng wrote:
> A call of the function ¡°do_take_over_console¡± can fail here.
> The corresponding system resources were not released then.
> Thus add a call of the function ¡°iounmap¡± together with the check
> of a failure predicate.
> 
> Fixes: e84de0c6190503 ("MIPS: GIO bus support for SGI IP22/28")

I cannot see how this patch fixes commit e84de0c6190503
(AFAICS npregs has also been leaked on error before)?

> CC: Andy Shevchenko <andy.shevchenko@...il.com>
> Signed-off-by: Dejin Zheng <zhengdejin5@...il.com>
> ---
> v1 -> v2:
> 	- modify the commit comments by Markus'suggestion.
> 
>  drivers/video/console/newport_con.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/video/console/newport_con.c b/drivers/video/console/newport_con.c
> index 00dddf6e08b0..6bfc8e3ffd4a 100644
> --- a/drivers/video/console/newport_con.c
> +++ b/drivers/video/console/newport_con.c
> @@ -720,6 +720,9 @@ static int newport_probe(struct gio_device *dev,
>  	console_lock();
>  	err = do_take_over_console(&newport_con, 0, MAX_NR_CONSOLES - 1, 1);
>  	console_unlock();
> +
> +	if (err)
> +		iounmap((void *)npregs);

Looks OK but while you are at it, could you please also add missing
release_mem_region() on error and on device removal:

	newport_addr = dev->resource.start + 0xF0000;
	if (!request_mem_region(newport_addr, 0x10000, "Newport"))
		return -ENODEV;

	npregs = (struct newport_regs *)/* ioremap cannot fail */
		ioremap(newport_addr, sizeof(struct newport_regs));
	console_lock();
	err = do_take_over_console(&newport_con, 0, MAX_NR_CONSOLES - 1, 1);
	console_unlock();
	return err;
}

static void newport_remove(struct gio_device *dev)
{
	give_up_console(&newport_con);
	iounmap((void *)npregs);
}

?

>  	return err;
>  }
>  

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics