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Date: Fri, 29 Mar 2024 10:39:21 +0100
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Gong Ruiqi <gongruiqi1@huawei.com>
Cc: Jiri Slaby <jirislaby@kernel.org>,
	Hugo Villeneuve <hvilleneuve@dimonoff.com>,
	Jon Ringle <jringle@gridpoint.com>, linux-serial@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	Wang Weiyang <wangweiyang2@huawei.com>, stable@vger.kernel.org
Subject: Re: [PATCH stable 5.10] serial: sc16is7xx: convert from _raw_ to
 _noinc_ regmap functions for FIFO
Message-ID: <2024032926-wielder-recreate-be4a@gregkh>
References: <20240318025259.1412353-1-gongruiqi1@huawei.com>
 <07a3c30d-5a81-4b99-8090-38753b650432@huawei.com>
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In-Reply-To: <07a3c30d-5a81-4b99-8090-38753b650432@huawei.com>

On Mon, Mar 18, 2024 at 11:14:13AM +0800, Gong Ruiqi wrote:
> Oops. + Cc stable@vger.kernel.org
> 
> On 2024/03/18 10:52, GONG, Ruiqi wrote:
> > From: Hugo Villeneuve <hvilleneuve@dimonoff.com>
> > 
> > commit dbf4ab821804df071c8b566d9813083125e6d97b upstream.
> > 
> > The SC16IS7XX IC supports a burst mode to access the FIFOs where the
> > initial register address is sent ($00), followed by all the FIFO data
> > without having to resend the register address each time. In this mode, the
> > IC doesn't increment the register address for each R/W byte.
> > 
> > The regmap_raw_read() and regmap_raw_write() are functions which can
> > perform IO over multiple registers. They are currently used to read/write
> > from/to the FIFO, and although they operate correctly in this burst mode on
> > the SPI bus, they would corrupt the regmap cache if it was not disabled
> > manually. The reason is that when the R/W size is more than 1 byte, these
> > functions assume that the register address is incremented and handle the
> > cache accordingly.
> > 
> > Convert FIFO R/W functions to use the regmap _noinc_ versions in order to
> > remove the manual cache control which was a workaround when using the
> > _raw_ versions. FIFO registers are properly declared as volatile so
> > cache will not be used/updated for FIFO accesses.
> > 
> > Fixes: dfeae619d781 ("serial: sc16is7xx")
> > Cc:  <stable@vger.kernel.org>
> > Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
> > Link: https://lore.kernel.org/r/20231211171353.2901416-6-hugo@hugovil.com
> > Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > Cc: Hugo Villeneuve <hvilleneuve@dimonoff.com>
> > Signed-off-by: GONG, Ruiqi <gongruiqi1@huawei.com>
> > ---
> > 
> > The mainline commit dbf4ab821804 ("serial: sc16is7xx: convert from _raw_
> > to _noinc_ regmap functions for FIFO") by Hugo has been assigned to be
> > CVE-2023-52488, but for stable branches lower than 6.1 there's no
> > official backport.
> > 
> > I made up this backport patch for 5.10, and its correctness has been
> > confirmed in previous communication with Hugo. Let's publicize it and
> > merge it into upstream.

I can not take this only in 5.10, it needs to also go into 5.15.y first,
right?

Please resend a 5.15.y and this 5.10.y version when you have both of
them (the 5.10.y version wasn't sent to stable@k.o so it's hard to track
down), and we will be glad to take them both.

thanks,

greg k-h