linux-kernel - Re: [PATCH 02/18] serial: sc16is7xx: fix invalid sc16is7xx

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Message-ID: <ZYMK-l03S86Nw19I@smile.fi.intel.com>
Date: Wed, 20 Dec 2023 17:40:42 +0200
From: Andy Shevchenko <andriy.shevchenko@...el.com>
To: Hugo Villeneuve <hugo@...ovil.com>
Cc: gregkh@...uxfoundation.org, jirislaby@...nel.org, jringle@...dpoint.com,
	kubakici@...pl, phil@...pberrypi.org, bo.svangard@...eddedart.se,
	linux-kernel@...r.kernel.org, linux-serial@...r.kernel.org,
	Hugo Villeneuve <hvilleneuve@...onoff.com>, stable@...r.kernel.org,
	Yury Norov <yury.norov@...il.com>
Subject: Re: [PATCH 02/18] serial: sc16is7xx: fix invalid sc16is7xx_lines
 bitfield in case of probe error

On Tue, Dec 19, 2023 at 12:18:46PM -0500, Hugo Villeneuve wrote:
> From: Hugo Villeneuve <hvilleneuve@...onoff.com>
> 
> If an error occurs during probing, the sc16is7xx_lines bitfield may be left
> in a state that doesn't represent the correct state of lines allocation.
> 
> For example, in a system with two SC16 devices, if an error occurs only
> during probing of channel (port) B of the second device, sc16is7xx_lines
> final state will be 00001011b instead of the expected 00000011b.
> 
> This is caused in part because of the "i--" in the for/loop located in
> the out_ports: error path.
> 
> Fix this by checking the return value of uart_add_one_port() and set line
> allocation bit only if this was successful. This allows the refactor of
> the obfuscated for(i--...) loop in the error path, and properly call
> uart_remove_one_port() only when needed, and properly unset line allocation
> bits.
> 
> Also use same mechanism in remove() when calling uart_remove_one_port().

Yes, this seems to be the correct one to fix the problem described in
the patch 1. I dunno why the patch 1 even exists.

As for Yury's patch, you are doing fixes, so your stuff has priority on his.

-- 
With Best Regards,
Andy Shevchenko