From nobody Mon Sep 29 20:18:43 2025 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 B5FD4C00140 for ; Mon, 15 Aug 2022 22:39:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1350422AbiHOWjY (ORCPT ); Mon, 15 Aug 2022 18:39:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53188 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1348988AbiHOWcr (ORCPT ); Mon, 15 Aug 2022 18:32:47 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7B6C971714; Mon, 15 Aug 2022 12:49:19 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 3FD2FB8114E; Mon, 15 Aug 2022 19:49:10 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9F2E4C433C1; Mon, 15 Aug 2022 19:49:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1660592949; bh=4pNbcfBY7sSXixtKDEXaS8TRXL9OvdOoDNaQXO+z7ao=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=xzr/na98crRsKbAz3Rfvf4rzOwGiaLiir/9jNxxZP8aJxPn8V3uZjTyubAtwyOq1l CgkRSX837CN2jjIdZ0/XFxdLMwTSZ+H+J3ZvKCkB+NGCIUqcE2s4CAKxMieA+5aYZq Eze0E3mfRu7M3g8AFgANFYLOhFp6yXaFKZMc10rY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= , Guenter Roeck , Sasha Levin Subject: [PATCH 5.19 0191/1157] hwmon: (sht15) Fix wrong assumptions in device remove callback Date: Mon, 15 Aug 2022 19:52:27 +0200 Message-Id: <20220815180447.391756473@linuxfoundation.org> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220815180439.416659447@linuxfoundation.org> References: <20220815180439.416659447@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Uwe Kleine-K=C3=B6nig [ Upstream commit 7d4edccc9bbfe1dcdff641343f7b0c6763fbe774 ] Taking a lock at the beginning of .remove() doesn't prevent new readers. With the existing approach it can happen, that a read occurs just when the lock was taken blocking the reader until the lock is released at the end of the remove callback which then accessed *data that is already freed then. To actually fix this problem the hwmon core needs some adaption. Until this is implemented take the optimistic approach of assuming that all readers are gone after hwmon_device_unregister() and sysfs_remove_group() as most other drivers do. (And once the core implements that, taking the lock would deadlock.) So drop the lock, move the reset to after device unregistration to keep the device in a workable state until it's deregistered. Also add a error message in case the reset fails and return 0 anyhow. (Returning an error code, doesn't stop the platform device unregistration and only results in a little helpful error message before the devm cleanup handlers are called.) Signed-off-by: Uwe Kleine-K=C3=B6nig Link: https://lore.kernel.org/r/20220725194344.150098-1-u.kleine-koenig@pen= gutronix.de Signed-off-by: Guenter Roeck Signed-off-by: Sasha Levin --- drivers/hwmon/sht15.c | 17 ++++++----------- 1 file changed, 6 insertions(+), 11 deletions(-) diff --git a/drivers/hwmon/sht15.c b/drivers/hwmon/sht15.c index 7f4a63959730..ae4d14257a11 100644 --- a/drivers/hwmon/sht15.c +++ b/drivers/hwmon/sht15.c @@ -1020,25 +1020,20 @@ static int sht15_probe(struct platform_device *pdev) static int sht15_remove(struct platform_device *pdev) { struct sht15_data *data =3D platform_get_drvdata(pdev); + int ret; =20 - /* - * Make sure any reads from the device are done and - * prevent new ones beginning - */ - mutex_lock(&data->read_lock); - if (sht15_soft_reset(data)) { - mutex_unlock(&data->read_lock); - return -EFAULT; - } hwmon_device_unregister(data->hwmon_dev); sysfs_remove_group(&pdev->dev.kobj, &sht15_attr_group); + + ret =3D sht15_soft_reset(data); + if (ret) + dev_err(&pdev->dev, "Failed to reset device (%pe)\n", ERR_PTR(ret)); + if (!IS_ERR(data->reg)) { regulator_unregister_notifier(data->reg, &data->nb); regulator_disable(data->reg); } =20 - mutex_unlock(&data->read_lock); - return 0; } =20 --=20 2.35.1