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Fri, 06 Nov 2026 09:37:03 -0800 (PST) Received: from google.com ([2a00:79e0:2ebe:8:64e:8358:c9cb:c17b]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-3b0f76ff45fsm983355a91.17.2026.11.06.09.36.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 06 Nov 2026 09:37:00 -0800 (PST) Date: Fri, 6 Nov 2026 09:36:57 -0800 From: Dmitry Torokhov To: Liu Chao Cc: Markus Schneider-Pargmann , Frank Li , Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam , Juergen Borleis , Denis Carikli , Lee Jones , fangxy@xiaopeng.com, linux-input@vger.kernel.org, imx@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH] Input: mx25-tcq - clamp the FIFO sample count to the buffer size Message-ID: References: <20261106075127.3105907-1-liuc63@xiaopeng.com> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261106075127.3105907-1-liuc63@xiaopeng.com> Hi Liu, On Fri, Nov 06, 2026 at 03:51:27PM +0800, Liu Chao wrote: > MX25_ADCQ_SR_FDN() reports up to 31 pending samples. The IRQ thread > aligns the count down to a multiple of the sample count but never > bounds it by the size of sample_buf, so a FIFO backlog larger than > TSC_MAX_SAMPLES overruns the stack buffer. > > Clamp the count before the alignment so that the result stays a > multiple of sample_count. > > Fixes: 4f7ed234f2a5 ("Input: touchscreen: Add imx25 TCQ driver") > Cc: stable@vger.kernel.org This is a platform device, not something that can be randomly connected. SO barring silicon issues the condition should never happen. I do not think this makes sense to backport this. > Signed-off-by: Liu Chao > --- > drivers/input/touchscreen/fsl-imx25-tcq.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/input/touchscreen/fsl-imx25-tcq.c b/drivers/input/touchscreen/fsl-imx25-tcq.c > index ff270b3b8572..fa8d8b736723 100644 > --- a/drivers/input/touchscreen/fsl-imx25-tcq.c > +++ b/drivers/input/touchscreen/fsl-imx25-tcq.c > @@ -319,6 +319,7 @@ static irqreturn_t mx25_tcq_irq_thread(int irq, void *dev_id) > */ > regmap_read(priv->regs, MX25_ADCQ_SR, &stats); > samples = MX25_ADCQ_SR_FDN(stats); > + samples = min_t(unsigned int, samples, TSC_MAX_SAMPLES); Why is it valid to clamp instead of refusing invalid data? > samples -= samples % priv->sample_count; > > if (!samples) Thanks. -- Dmitry