From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4A12911731 for ; Thu, 24 Aug 2023 14:59:52 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C548BC433C8; Thu, 24 Aug 2023 14:59:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1692889192; bh=jtzxm85/7FGHSl1UcsSqflXZbGwlIKrqYPKTjC4haQY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XgnyhdqKCaUXi4aty3A2cMw79+pWTltOAxQAHTkkvL1ARe3p8nW9Zic8RyIkymQQz 1rvVogWMC1K9tKRQPTsXzcyuZR4MFmODbnpnR7iTratJDSAuFOlGMcmCBxisjlz53Z xgjQXb8Oco5/Tuw53IjLPeV3be+gAtkR+NKgmQxA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, William Breathitt Gray , Stable@vger.kernel.org, Jonathan Cameron , Sasha Levin Subject: [PATCH 5.10 047/135] iio: addac: stx104: Fix race condition when converting analog-to-digital Date: Thu, 24 Aug 2023 16:49:50 +0200 Message-ID: <20230824145028.972189144@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20230824145027.008282920@linuxfoundation.org> References: <20230824145027.008282920@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: William Breathitt Gray [ Upstream commit 4f9b80aefb9e2f542a49d9ec087cf5919730e1dd ] The ADC conversion procedure requires several device I/O operations performed in a particular sequence. If stx104_read_raw() is called concurrently, the ADC conversion procedure could be clobbered. Prevent such a race condition by utilizing a mutex. Fixes: 4075a283ae83 ("iio: stx104: Add IIO support for the ADC channels") Signed-off-by: William Breathitt Gray Link: https://lore.kernel.org/r/2ae5e40eed5006ca735e4c12181a9ff5ced65547.1680790580.git.william.gray@linaro.org Cc: Signed-off-by: Jonathan Cameron Signed-off-by: Sasha Levin --- drivers/iio/adc/stx104.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/iio/adc/stx104.c b/drivers/iio/adc/stx104.c index e110a910235ff..b658a75d4e3a8 100644 --- a/drivers/iio/adc/stx104.c +++ b/drivers/iio/adc/stx104.c @@ -117,6 +117,8 @@ static int stx104_read_raw(struct iio_dev *indio_dev, return IIO_VAL_INT; } + mutex_lock(&priv->lock); + /* select ADC channel */ iowrite8(chan->channel | (chan->channel << 4), ®->achan); @@ -127,6 +129,8 @@ static int stx104_read_raw(struct iio_dev *indio_dev, while (ioread8(®->cir_asr) & BIT(7)); *val = ioread16(®->ssr_ad); + + mutex_unlock(&priv->lock); return IIO_VAL_INT; case IIO_CHAN_INFO_OFFSET: /* get ADC bipolar/unipolar configuration */ -- 2.40.1