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Mon, 27 Apr 2026 01:48:41 -0700 (PDT) Received: from [10.11.12.108] ([79.115.63.228]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-43fe4cc2cacsm79702504f8f.13.2026.04.27.01.48.40 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 27 Apr 2026 01:48:41 -0700 (PDT) Message-ID: <84c292d8-d2a0-4c29-bd28-cc00f66c2f43@linaro.org> Date: Mon, 27 Apr 2026 11:48:38 +0300 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] firmware: samsung: fix stale response flag in acpm_prepare_xfer() To: Titouan Ameline de Cadeville Cc: krzk@kernel.org, alim.akhtar@samsung.com, linux-kernel@vger.kernel.org, linux-samsung-soc@vger.kernel.org, linux-arm-kernel@lists.infradead.org References: <20260426210255.73674-1-titouan.ameline@gmail.com> Content-Language: en-US From: Tudor Ambarus In-Reply-To: <20260426210255.73674-1-titouan.ameline@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260427_014844_424014_146A64E1 X-CRM114-Status: GOOD ( 17.62 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi, Thanks for the patch! On 4/27/26 12:02 AM, Titouan Ameline de Cadeville wrote: > acpm_prepare_xfer() only ever set rx_data->response to true, never > false. A reused sequence number slot could therefore inherit a stale > true from a previous transfer that expected a response, causing > acpm_get_rx() to enter the response-copy path for a fire-and-forget > transfer whose rxd is NULL. > > Unconditionally assign the correct boolean value so the slot is fully > reset on every reuse. > How did you find this? Sashiko identified this too when reviewing the ACPM thermal patches. I sent some fixes last week, where this bug is squashed as well: https://lore.kernel.org/linux-samsung-soc/20260423-acpm-fixes-sashiko-reports-v1-0-2217b790925e@linaro.org/T/#m1c32aa4c84ea7e3909bc8fe7599585b71e95d8b5 Thanks! ta > Fixes: a88927b534ba ("firmware: add Exynos ACPM protocol driver") > Signed-off-by: Titouan Ameline de Cadeville > --- > drivers/firmware/samsung/exynos-acpm.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/drivers/firmware/samsung/exynos-acpm.c b/drivers/firmware/samsung/exynos-acpm.c > index 16c46ed60837..2fee6bb60efc 100644 > --- a/drivers/firmware/samsung/exynos-acpm.c > +++ b/drivers/firmware/samsung/exynos-acpm.c > @@ -380,8 +380,7 @@ static void acpm_prepare_xfer(struct acpm_chan *achan, > /* Clear data for upcoming responses */ > rx_data = &achan->rx_data[achan->seqnum - 1]; > memset(rx_data->cmd, 0, sizeof(*rx_data->cmd) * rx_data->n_cmd); > - if (xfer->rxd) > - rx_data->response = true; > + rx_data->response = !!xfer->rxd; > > /* Flag the index based on seqnum. (seqnum: 1~63, bitmap: 0~62) */ > set_bit(achan->seqnum - 1, achan->bitmap_seqnum);