From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C348745C1C; Mon, 4 Mar 2024 15:02:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709564572; cv=none; b=Kz5VhIYpzirqUIUSJJ45LddlPxrcqFzxFIL56CDT75hJaX9lEvsKomH2XyXuj0dZllpkukt6hk/FmjOsDY3JopaNuruJ3oGtwh8FlYdxCs362ReFkgsgtc+c7HAnMKqCGMhFFZYAHnuv+/GLt5Hoid2wUAODP0lThQ6KQ18gBmM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709564572; c=relaxed/simple; bh=NJq21IcMWpBFi3GGq2wDJ4XI/iHf+aVc6N3sYqI37K4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=kET5vrKOGqZeYj/GWGBlB5nSSpT/yfJXiZGtCr8DfVx15+YwKUC1CeEhXbxnjo3Ep1/uWv/3l9wSSAiqwYs1bTaqujxH8/Bn8L89IxQ8wEHHraVXtdjWYUDvzEu85sudeDZbDeemKpKudUbODgh3WQ7C989KegMD/p0U7F6btrE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=pPl++o7H; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="pPl++o7H" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0B4D6C433C7; Mon, 4 Mar 2024 15:02:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1709564572; bh=NJq21IcMWpBFi3GGq2wDJ4XI/iHf+aVc6N3sYqI37K4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=pPl++o7H+Cp4Q6tf5O3Gj21PmjH/SJB5KIG/HCbhHd+d2INNQ1h7QmlnC8Vb9W32V Tg3WhQHabCbF9Qjg58PGwYUQ4lDBiAhASMp06MukKsYJRoUKpHoF+Ue/C+k/4hO1Di lUUmjRjzJmjGy6CKSG2AHh05sP4j9rWWJwqjT1CrPyMUbkmIh5/BVJmf6QG75f9TP5 gNBJPT3gjkBkquIWINkwlFbbzcfuBLF2ysl3ITRfkAZleDFoJ1hTECubVUrvwHJN0M T7itKqVY1rEOQOvLQJDfPZCdjHyvXE5Xdom4cy8ERuvXU02nA5nVeYNZs8fBA6QX/I 4m8OF9OtZra1g== Date: Mon, 4 Mar 2024 09:02:48 -0600 From: Rob Herring To: Herve Codina , Saravana Kannan Cc: Greg Kroah-Hartman , "Rafael J. Wysocki" , Frank Rowand , Lizhi Hou , Max Zhen , Sonal Santan , Stefano Stabellini , Jonathan Cameron , linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, Allan Nielsen , Horatiu Vultur , Steen Hegelund , Luca Ceresoli , Nuno Sa , Thomas Petazzoni Subject: Re: [PATCH v3 0/2] Synchronize DT overlay removal with devlink removals Message-ID: <20240304150248.GA211460-robh@kernel.org> References: <20240229105204.720717-1-herve.codina@bootlin.com> Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20240229105204.720717-1-herve.codina@bootlin.com> On Thu, Feb 29, 2024 at 11:52:01AM +0100, Herve Codina wrote: > Hi, Please CC Saravana on this. > > In the following sequence: > of_platform_depopulate(); /* Remove devices from a DT overlay node */ > of_overlay_remove(); /* Remove the DT overlay node itself */ > > Some warnings are raised by __of_changeset_entry_destroy() which was > called from of_overlay_remove(): > ERROR: memory leak, expected refcount 1 instead of 2 ... > > The issue is that, during the device devlink removals triggered from the > of_platform_depopulate(), jobs are put in a workqueue. > These jobs drop the reference to the devices. When a device is no more > referenced (refcount == 0), it is released and the reference to its > of_node is dropped by a call to of_node_put(). > These operations are fully correct except that, because of the > workqueue, they are done asynchronously with respect to function calls. > > In the sequence provided, the jobs are run too late, after the call to > __of_changeset_entry_destroy() and so a missing of_node_put() call is > detected by __of_changeset_entry_destroy(). > > This series fixes this issue introducing device_link_wait_removal() in > order to wait for the end of jobs execution (patch 1) and using this > function to synchronize the overlay removal with the end of jobs > execution (patch 2). > > Compared to the previous iteration: > https://lore.kernel.org/linux-kernel/20231130174126.688486-1-herve.codina@bootlin.com/ > this v3 series: > - add the missing device.h > > This series handles cases reported by Luca [1] and Nuno [2]. > [1]: https://lore.kernel.org/all/20231220181627.341e8789@booty/ > [2]: https://lore.kernel.org/all/20240205-fix-device-links-overlays-v2-2-5344f8c79d57@analog.com/ > > Best regards, > Hervé > > Changes v2 -> v3 > - Patch 1 > No changes > > - Patch 2 > Add missing device.h > > Changes v1 -> v2 > - Patch 1 > Rename the workqueue to 'device_link_wq' > Add 'Fixes' tag and Cc stable > > - Patch 2 > Add device.h inclusion. > Call device_link_wait_removal() later in the overlay removal > sequence (i.e. in free_overlay_changeset() function). > Drop of_mutex lock while calling device_link_wait_removal(). > Add 'Fixes' tag and Cc stable > > Herve Codina (2): > driver core: Introduce device_link_wait_removal() > of: overlay: Synchronize of_overlay_remove() with the devlink removals > > drivers/base/core.c | 26 +++++++++++++++++++++++--- > drivers/of/overlay.c | 10 +++++++++- > include/linux/device.h | 1 + > 3 files changed, 33 insertions(+), 4 deletions(-) > > -- > 2.43.0 >