From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7D5A2EE49AD for ; Thu, 24 Aug 2023 14:55:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241884AbjHXOzN (ORCPT ); Thu, 24 Aug 2023 10:55:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38502 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241947AbjHXOzE (ORCPT ); Thu, 24 Aug 2023 10:55:04 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3D90519AD for ; Thu, 24 Aug 2023 07:55:02 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id C704062248 for ; Thu, 24 Aug 2023 14:55:01 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D852AC433C9; Thu, 24 Aug 2023 14:55:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1692888901; bh=opTnSMNIR+R65o7QhROTrAXgr1TSY+y6iHiiIToHdSM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=u+9nS6f5D0YMGNqxRNLN5ei9ZnPd/AS5PWs7L8cSyHm03F8APQmCtWCQj6gIJ1dyJ SrEScuYPC5LcOiLXv4K/egn5yWnFBmnSVdKIgTlPEIKKbEV8Pu/UHgXmbRQe/evd/x NqKHArVzSwPKtwVr8IiRRGUCii98Jm+8oqOOrV0s= 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 5.15 044/139] iio: addac: stx104: Fix race condition for stx104_write_raw() Date: Thu, 24 Aug 2023 16:49:27 +0200 Message-ID: <20230824145025.536921538@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20230824145023.559380953@linuxfoundation.org> References: <20230824145023.559380953@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: William Breathitt Gray [ Upstream commit 9740827468cea80c42db29e7171a50e99acf7328 ] The priv->chan_out_states array and actual DAC value can become mismatched if stx104_write_raw() is called concurrently. Prevent such a race condition by utilizing a mutex. Fixes: 97a445dad37a ("iio: Add IIO support for the DAC on the Apex Embedded Systems STX104") Signed-off-by: William Breathitt Gray Link: https://lore.kernel.org/r/c95c9a77fcef36b2a052282146950f23bbc1ebdc.1680790580.git.william.gray@linaro.org Cc: Signed-off-by: Jonathan Cameron Stable-dep-of: 4f9b80aefb9e ("iio: addac: stx104: Fix race condition when converting analog-to-digital") Signed-off-by: Sasha Levin --- drivers/iio/addac/stx104.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/iio/addac/stx104.c b/drivers/iio/addac/stx104.c index 48a91a95e597b..e110a910235ff 100644 --- a/drivers/iio/addac/stx104.c +++ b/drivers/iio/addac/stx104.c @@ -15,6 +15,7 @@ #include #include #include +#include #include #include @@ -69,10 +70,12 @@ struct stx104_reg { /** * struct stx104_iio - IIO device private data structure + * @lock: synchronization lock to prevent I/O race conditions * @chan_out_states: channels' output states * @reg: I/O address offset for the device registers */ struct stx104_iio { + struct mutex lock; unsigned int chan_out_states[STX104_NUM_OUT_CHAN]; struct stx104_reg __iomem *reg; }; @@ -178,9 +181,12 @@ static int stx104_write_raw(struct iio_dev *indio_dev, if ((unsigned int)val > 65535) return -EINVAL; + mutex_lock(&priv->lock); + priv->chan_out_states[chan->channel] = val; iowrite16(val, &priv->reg->dac[chan->channel]); + mutex_unlock(&priv->lock); return 0; } return -EINVAL; @@ -351,6 +357,8 @@ static int stx104_probe(struct device *dev, unsigned int id) indio_dev->name = dev_name(dev); + mutex_init(&priv->lock); + /* configure device for software trigger operation */ iowrite8(0, &priv->reg->acr); -- 2.40.1