From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Fri, 23 Aug 2013 17:22:15 +0200 (CEST) Received: from mailout2.w1.samsung.com ([210.118.77.12]:49596 "EHLO mailout2.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by eddie.linux-mips.org with ESMTP id S6822345Ab3HWPWL0FyGV (ORCPT ); Fri, 23 Aug 2013 17:22:11 +0200 Received: from eucpsbgm2.samsung.com (unknown [203.254.199.245]) by mailout2.w1.samsung.com (Oracle Communications Messaging Server 7u4-24.01(7.0.4.24.0) 64bit (built Nov 17 2011)) with ESMTP id <0MRZ0040PPCD27B0@mailout2.w1.samsung.com>; Fri, 23 Aug 2013 16:22:03 +0100 (BST) X-AuditID: cbfec7f5-b7ef66d00000795a-f2-52177e1bde11 Received: from eusync3.samsung.com ( [203.254.199.213]) by eucpsbgm2.samsung.com (EUCPMTA) with SMTP id BD.F5.31066.B1E77125; Fri, 23 Aug 2013 16:22:03 +0100 (BST) Received: from [106.116.147.32] by eusync3.samsung.com (Oracle Communications Messaging Server 7u4-23.01(7.0.4.23.0) 64bit (built Aug 10 2011)) with ESMTPA id <0MRZ00BQTPCQLJ70@eusync3.samsung.com>; Fri, 23 Aug 2013 16:22:03 +0100 (BST) Message-id: <52177E19.3080106@samsung.com> Date: Fri, 23 Aug 2013 17:22:01 +0200 From: Sylwester Nawrocki User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/17.0 Thunderbird/17.0 MIME-version: 1.0 To: linux-arm-kernel@lists.infradead.org Cc: Sylwester Nawrocki , linux@arm.linux.org.uk, mturquette@linaro.org, jiada_wang@mentor.com, broonie@kernel.org, vapier@gentoo.org, ralf@linux-mips.org, kyungmin.park@samsung.com, myungjoo.ham@samsung.com, shawn.guo@linaro.org, sebastian.hesselbarth@gmail.com, LW@KARO-electronics.de, t.figa@samsung.com, g.liakhovetski@gmx.de, laurent.pinchart@ideasonboard.com, linux-kernel@vger.kernel.org, uclinux-dist-devel@blackfin.uclinux.org, linux-mips@linux-mips.org, linux-sh@vger.kernel.org Subject: Re: [PATCH v3 2/5] clkdev: Fix race condition in clock lookup from device tree References: <1377270227-1030-1-git-send-email-s.nawrocki@samsung.com> <1377270227-1030-3-git-send-email-s.nawrocki@samsung.com> In-reply-to: <1377270227-1030-3-git-send-email-s.nawrocki@samsung.com> Content-type: text/plain; charset=ISO-8859-1 Content-transfer-encoding: 7bit X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFlrMIsWRmVeSWpSXmKPExsVy+t/xq7rSdeJBBi2bRSymPnzCZvF+4zwm i54/lRZnm96wW3ROXMJusenxNVaLy7vmsFlMmDqJ3WLOnynMFrcv81oceLKczeLphItsFrcb V7BZXNqjYnH4TTurxfufjhZP1y1htlg/4zWLxcKGL+wWNyf8YHYQ8Whp7mHzWDnd2+Py9zfM Hjtn3WX3+PAxzmN2x0xWj/nTHzF7bFrVyeZx59oeNo+jK9cyeWxeUu+x+2sTo0ffllWMHp83 yQXwRXHZpKTmZJalFunbJXBlHN/zn73gG3vF3pu/WBoYz7F1MXJySAiYSHzof8QCYYtJXLi3 HiwuJLCUUWLuH1YI+xOjxL4dziA2r4CWxOa+h2D1LAKqEp/vfWQHsdkEDCV6j/YxgtiiAgES i5ecY4eoF5T4MfkeWL2IgIbElK7HYHFmgV4WiUOLjbsYOTiEBSIlZmwACnMBrWpklFjcPx/s Bk4BN4lrzfOYIep1JPa3TmODsOUlNq95yzyBUWAWkhWzkJTNQlK2gJF5FaNoamlyQXFSeq6R XnFibnFpXrpecn7uJkZIxH7dwbj0mNUhRgEORiUe3gnOYkFCrIllxZW5hxglOJiVRHifVosH CfGmJFZWpRblxxeV5qQWH2Jk4uCUamA89Z1jp1H5jYQnTTvYEzp8Kzh/v5tve/Uei8j+n3df SujeNJFWq78T/sHoWunS/byBl4J7Tjr6zfjyX2ejj+xrjnWXf7DquS+Vb2fQzlPUNwl0mDw5 QtrVe3qlt8jXxScWRUid5O8y0WhI2Tn9Wotq7sxTt4SOb3bxLXkdt14ze8Xjw52uFcpKLMUZ iYZazEXFiQAP3jeLtgIAAA== Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 37665 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: s.nawrocki@samsung.com Precedence: bulk List-help: List-unsubscribe: List-software: Ecartis version 1.0.0 List-Id: linux-mips X-List-ID: linux-mips List-subscribe: List-owner: List-post: List-archive: X-list: linux-mips On 08/23/2013 05:03 PM, Sylwester Nawrocki wrote: > There is currently a race condition in the device tree part of clk_get() > function, since the pointer returned from of_clk_get_by_name() may become > invalid before __clk_get() call. I.e. due to the clock provider driver > remove() callback being called in between of_clk_get_by_name() and > __clk_get(). > > Fix this by doing both the look up and __clk_get() operations with the > clock providers list mutex held. This ensures that the clock pointer > returned from __of_clk_get_from_provider() call and passed to __clk_get() > is valid, as long as the clock supplier module first removes its clock > provider instance and then does clk_unregister() on the corresponding > clocks. > > Signed-off-by: Sylwester Nawrocki > Signed-off-by: Kyungmin Park Oops, I missed to add: Reviewed-by: Mike Turquette > Acked-by: Russell King From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sylwester Nawrocki Date: Fri, 23 Aug 2013 15:22:01 +0000 Subject: Re: [PATCH v3 2/5] clkdev: Fix race condition in clock lookup from device tree Message-Id: <52177E19.3080106@samsung.com> List-Id: References: <1377270227-1030-1-git-send-email-s.nawrocki@samsung.com> <1377270227-1030-3-git-send-email-s.nawrocki@samsung.com> In-Reply-To: <1377270227-1030-3-git-send-email-s.nawrocki@samsung.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-arm-kernel@lists.infradead.org On 08/23/2013 05:03 PM, Sylwester Nawrocki wrote: > There is currently a race condition in the device tree part of clk_get() > function, since the pointer returned from of_clk_get_by_name() may become > invalid before __clk_get() call. I.e. due to the clock provider driver > remove() callback being called in between of_clk_get_by_name() and > __clk_get(). > > Fix this by doing both the look up and __clk_get() operations with the > clock providers list mutex held. This ensures that the clock pointer > returned from __of_clk_get_from_provider() call and passed to __clk_get() > is valid, as long as the clock supplier module first removes its clock > provider instance and then does clk_unregister() on the corresponding > clocks. > > Signed-off-by: Sylwester Nawrocki > Signed-off-by: Kyungmin Park Oops, I missed to add: Reviewed-by: Mike Turquette > Acked-by: Russell King From mboxrd@z Thu Jan 1 00:00:00 1970 From: s.nawrocki@samsung.com (Sylwester Nawrocki) Date: Fri, 23 Aug 2013 17:22:01 +0200 Subject: [PATCH v3 2/5] clkdev: Fix race condition in clock lookup from device tree In-Reply-To: <1377270227-1030-3-git-send-email-s.nawrocki@samsung.com> References: <1377270227-1030-1-git-send-email-s.nawrocki@samsung.com> <1377270227-1030-3-git-send-email-s.nawrocki@samsung.com> Message-ID: <52177E19.3080106@samsung.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 08/23/2013 05:03 PM, Sylwester Nawrocki wrote: > There is currently a race condition in the device tree part of clk_get() > function, since the pointer returned from of_clk_get_by_name() may become > invalid before __clk_get() call. I.e. due to the clock provider driver > remove() callback being called in between of_clk_get_by_name() and > __clk_get(). > > Fix this by doing both the look up and __clk_get() operations with the > clock providers list mutex held. This ensures that the clock pointer > returned from __of_clk_get_from_provider() call and passed to __clk_get() > is valid, as long as the clock supplier module first removes its clock > provider instance and then does clk_unregister() on the corresponding > clocks. > > Signed-off-by: Sylwester Nawrocki > Signed-off-by: Kyungmin Park Oops, I missed to add: Reviewed-by: Mike Turquette > Acked-by: Russell King