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 X-Spam-Level: X-Spam-Status: No, score=-20.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 421C5C07E9E for ; Sun, 4 Jul 2021 23:10:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2DE166194D for ; Sun, 4 Jul 2021 23:10:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231920AbhGDXNP (ORCPT ); Sun, 4 Jul 2021 19:13:15 -0400 Received: from mail.kernel.org ([198.145.29.99]:49476 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231877AbhGDXJ3 (ORCPT ); Sun, 4 Jul 2021 19:09:29 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 109746141C; Sun, 4 Jul 2021 23:06:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1625440013; bh=QscHBCdwyz845ByNO9AmsX1v5TFqG9DVE99wooaq7oI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=gTAvng+9JxIiC15rwveaMIveejq7kfyZJ+zA5PeeGmVpB9zuhwFStJbFj5dKEaSzX bVls625rN4X22QW2LYPiYwPUScwkBdoPsRDuMfvE8VvpAxl0A3zAizI3hr2rvNlUdj xVISDDiohb1FaBrLLjF8V5L2M26RY4TI+llg6FCFgBU4fJp7xUvkY2oR6R6GxJIBNh 8Nztjm8wrLQOQzJ2bN7nNskO13367l5zJxL6QllELhkVlIDbIvo3rRTV+DADvG9sVC Z9mOuiCaUghhY0erD6eNRhwex+scSTBsCOuUhWe5vclX71i8ggCkPBTirQA47XRGy0 gdj7NXIkg2H1Q== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Hans Verkuil , Mauro Carvalho Chehab , Sasha Levin , linux-media@vger.kernel.org Subject: [PATCH AUTOSEL 5.12 27/80] media: cobalt: fix race condition in setting HPD Date: Sun, 4 Jul 2021 19:05:23 -0400 Message-Id: <20210704230616.1489200-27-sashal@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210704230616.1489200-1-sashal@kernel.org> References: <20210704230616.1489200-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org From: Hans Verkuil [ Upstream commit 3d37ef41bed0854805ab9af22c422267510e1344 ] The cobalt_s_bit_sysctrl reads the old register value over PCI, then changes a bit and sets writes the new value to the register. This is used among other things for setting the HPD output pin. But if the HPD is changed for multiple inputs at the same time, then this causes a race condition where a stale value is read. Serialize this function with a mutex. Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Sasha Levin --- drivers/media/pci/cobalt/cobalt-driver.c | 1 + drivers/media/pci/cobalt/cobalt-driver.h | 7 ++++++- 2 files changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/media/pci/cobalt/cobalt-driver.c b/drivers/media/pci/cobalt/cobalt-driver.c index 0695078ef812..1bd8bbe57a30 100644 --- a/drivers/media/pci/cobalt/cobalt-driver.c +++ b/drivers/media/pci/cobalt/cobalt-driver.c @@ -667,6 +667,7 @@ static int cobalt_probe(struct pci_dev *pci_dev, return -ENOMEM; cobalt->pci_dev = pci_dev; cobalt->instance = i; + mutex_init(&cobalt->pci_lock); retval = v4l2_device_register(&pci_dev->dev, &cobalt->v4l2_dev); if (retval) { diff --git a/drivers/media/pci/cobalt/cobalt-driver.h b/drivers/media/pci/cobalt/cobalt-driver.h index bca68572b324..12c33e035904 100644 --- a/drivers/media/pci/cobalt/cobalt-driver.h +++ b/drivers/media/pci/cobalt/cobalt-driver.h @@ -251,6 +251,8 @@ struct cobalt { int instance; struct pci_dev *pci_dev; struct v4l2_device v4l2_dev; + /* serialize PCI access in cobalt_s_bit_sysctrl() */ + struct mutex pci_lock; void __iomem *bar0, *bar1; @@ -320,10 +322,13 @@ static inline u32 cobalt_g_sysctrl(struct cobalt *cobalt) static inline void cobalt_s_bit_sysctrl(struct cobalt *cobalt, int bit, int val) { - u32 ctrl = cobalt_read_bar1(cobalt, COBALT_SYS_CTRL_BASE); + u32 ctrl; + mutex_lock(&cobalt->pci_lock); + ctrl = cobalt_read_bar1(cobalt, COBALT_SYS_CTRL_BASE); cobalt_write_bar1(cobalt, COBALT_SYS_CTRL_BASE, (ctrl & ~(1UL << bit)) | (val << bit)); + mutex_unlock(&cobalt->pci_lock); } static inline u32 cobalt_g_sysstat(struct cobalt *cobalt) -- 2.30.2