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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,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 41F55C433E2 for ; Thu, 28 May 2020 11:56:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 22B1F2074B for ; Thu, 28 May 2020 11:56:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590666985; bh=5EMxD/AfSpLyjuXNqb5ixny+nHiT+Kx9uhypSmTttzI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=EAfeX17T7JEuOtB6Ea0D0pAUy/BEgpleANiofpFfz8RJAdgLpDApCfd4uafh3X5cR /nSCH9W8/TXh24xVyctc7/WV97CiRBEWolfc9wl4FFce2hxY9vNla9lBBnVu6iQ+rt OyZ+uEYvHRIsFWTX9HCMzas/qhemiGDN7HJG4olM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388714AbgE1L4X (ORCPT ); Thu, 28 May 2020 07:56:23 -0400 Received: from mail.kernel.org ([198.145.29.99]:48130 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388647AbgE1L4M (ORCPT ); Thu, 28 May 2020 07:56:12 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id CC37E21531; Thu, 28 May 2020 11:56:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590666971; bh=5EMxD/AfSpLyjuXNqb5ixny+nHiT+Kx9uhypSmTttzI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=eoXXFhoyH60ylIhe285pCSmxnHsUiCzb3InJOF0+bK6niT8A7gDnAycxEAV7g78H8 d7yQSaJ7JxwU89zvyavV+ktULkJ7zHdsgVc5aPzqr90sx+AnALUtv+Qo4L04trRCzR 5fBWfp1HBFwsjO+iU1KPiNj78HYeQ3STLXlzU1BM= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Atsushi Nemoto , Thor Thayer , Wolfram Sang , Sasha Levin , linux-i2c@vger.kernel.org Subject: [PATCH AUTOSEL 5.6 09/47] i2c: altera: Fix race between xfer_msg and isr thread Date: Thu, 28 May 2020 07:55:22 -0400 Message-Id: <20200528115600.1405808-9-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200528115600.1405808-1-sashal@kernel.org> References: <20200528115600.1405808-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Atsushi Nemoto [ Upstream commit 5d4c7977499a736f3f80826bdc9744344ad55589 ] Use a mutex to protect access to idev->msg_len, idev->buf, etc. which are modified by both altr_i2c_xfer_msg() and altr_i2c_isr(). This is the minimal fix for easy backporting. A cleanup to remove the spinlock will be added later. Signed-off-by: Atsushi Nemoto Acked-by: Thor Thayer [wsa: updated commit message] Signed-off-by: Wolfram Sang Signed-off-by: Sasha Levin --- drivers/i2c/busses/i2c-altera.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/drivers/i2c/busses/i2c-altera.c b/drivers/i2c/busses/i2c-altera.c index 92d2c706c2a7..a60042431370 100644 --- a/drivers/i2c/busses/i2c-altera.c +++ b/drivers/i2c/busses/i2c-altera.c @@ -70,6 +70,7 @@ * @isr_mask: cached copy of local ISR enables. * @isr_status: cached copy of local ISR status. * @lock: spinlock for IRQ synchronization. + * @isr_mutex: mutex for IRQ thread. */ struct altr_i2c_dev { void __iomem *base; @@ -86,6 +87,7 @@ struct altr_i2c_dev { u32 isr_mask; u32 isr_status; spinlock_t lock; /* IRQ synchronization */ + struct mutex isr_mutex; }; static void @@ -245,10 +247,11 @@ static irqreturn_t altr_i2c_isr(int irq, void *_dev) struct altr_i2c_dev *idev = _dev; u32 status = idev->isr_status; + mutex_lock(&idev->isr_mutex); if (!idev->msg) { dev_warn(idev->dev, "unexpected interrupt\n"); altr_i2c_int_clear(idev, ALTR_I2C_ALL_IRQ); - return IRQ_HANDLED; + goto out; } read = (idev->msg->flags & I2C_M_RD) != 0; @@ -301,6 +304,8 @@ static irqreturn_t altr_i2c_isr(int irq, void *_dev) complete(&idev->msg_complete); dev_dbg(idev->dev, "Message Complete\n"); } +out: + mutex_unlock(&idev->isr_mutex); return IRQ_HANDLED; } @@ -312,6 +317,7 @@ static int altr_i2c_xfer_msg(struct altr_i2c_dev *idev, struct i2c_msg *msg) u32 value; u8 addr = i2c_8bit_addr_from_msg(msg); + mutex_lock(&idev->isr_mutex); idev->msg = msg; idev->msg_len = msg->len; idev->buf = msg->buf; @@ -336,6 +342,7 @@ static int altr_i2c_xfer_msg(struct altr_i2c_dev *idev, struct i2c_msg *msg) altr_i2c_int_enable(idev, imask, true); altr_i2c_fill_tx_fifo(idev); } + mutex_unlock(&idev->isr_mutex); time_left = wait_for_completion_timeout(&idev->msg_complete, ALTR_I2C_XFER_TIMEOUT); @@ -409,6 +416,7 @@ static int altr_i2c_probe(struct platform_device *pdev) idev->dev = &pdev->dev; init_completion(&idev->msg_complete); spin_lock_init(&idev->lock); + mutex_init(&idev->isr_mutex); ret = device_property_read_u32(idev->dev, "fifo-size", &idev->fifo_size); -- 2.25.1