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 BE9862C191; Fri, 8 Mar 2024 20:05:51 +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=1709928351; cv=none; b=aXIJfgqxouBDkvycqrjHyL1ggrqFfjv5Wz6J3utaCVLF+nS6lWFWtWslqT37iyNONH7ZLeRnPNUORtS//2rgmWkHB5wtIGuhrqImv3b5C6eIGQ4dyxKrsDNYAqVhdXzKINlg59978AOfhRENc101+PrYesY3D2CFUGBxr9FDepI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709928351; c=relaxed/simple; bh=Fjbr8IfY/JuQgJCrOKUOPWAPqtOc7XVMJSi1kxk8q3g=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=lgFC7ZnuQVTLIUWe3H4tooYmnFCqg7zQw90PR5SpySHrfvepvNeea7+o/tch5d8MYv6l29R96AbNlj0HvZY1QrQkxwm3hqP11PXmMHuoaYXuk1ZwhqGAowrcxcijM/ER1XBdEBtwoE9BhX2ycYRSmZonfiqD5olc179yZC5hJNk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=E9jKrthm; 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="E9jKrthm" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 12EF0C433F1; Fri, 8 Mar 2024 20:05:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1709928351; bh=Fjbr8IfY/JuQgJCrOKUOPWAPqtOc7XVMJSi1kxk8q3g=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=E9jKrthmWHS+OdgLrwbXboECUrSiykTuI9kCerRbgKkz2bvcXESmeXA80yTdOgpUN S7o4GOEOpvEsVgO0f7+REU2to6D4AE32EJ5VqGoi4wnC0EUwqdCsNrG7M9j3wXtt8h Cq5x4r130Hl9f1bnmzjE9SfToCGdbSmiYwNFZBVx1O77K8A5B0p5/5YbYcyLbBHYDZ t8ygjfbPSI367U8m2GZ4yKyNPfc/P6x0AAXMhGsW4rSfhE2v7HpBbS3xXyOYAV7Dt2 9cUh52J42UfNoelFPa0//kYfpi6xUiVvemlbMMyh8uJ5RNxtl+qZhJdoAl+ekaMEnO e687xCWQTqDLA== Date: Fri, 8 Mar 2024 14:05:48 -0600 From: Rob Herring To: Herve Codina Cc: Greg Kroah-Hartman , "Rafael J. Wysocki" , Frank Rowand , Saravana Kannan , 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 v5 0/2] Synchronize DT overlay removal with devlink removals Message-ID: <20240308200548.GA1189199-robh@kernel.org> References: <20240307111036.225007-1-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: <20240307111036.225007-1-herve.codina@bootlin.com> On Thu, Mar 07, 2024 at 12:09:59PM +0100, Herve Codina wrote: > Hi, > > 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/20240306085007.169771-1-herve.codina@bootlin.com/ > this v5 series: > - Remove a 'Fixes' tag > - Update a comment > - Add 'Tested-by' and ''Reviewed-by' tags > > 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 v4 -> v5 > - Patch 1 > Remove the 'Fixes' tag > Add 'Tested-by: Luca Ceresoli ' > Add 'Reviewed-by: Nuno Sa ' > > - Patch 2 > Update comment as suggested > Add 'Reviewed-by: Saravana Kannan ' > Add 'Tested-by: Luca Ceresoli ' > Add 'Reviewed-by: Nuno Sa ' > > Changes v3 -> v4 > - Patch 1 > Uses flush_workqueue() instead of drain_workqueue(). > > - Patch 2 > Remove unlock/re-lock when calling device_link_wait_removal() > Move device_link_wait_removal() call to of_changeset_destroy() > Update commit log > > 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: dynamic: Synchronize of_changeset_destroy() with the devlink > removals > > drivers/base/core.c | 26 +++++++++++++++++++++++--- > drivers/of/dynamic.c | 12 ++++++++++++ > include/linux/device.h | 1 + > 3 files changed, 36 insertions(+), 3 deletions(-) This looks good to me. I can take this given the user is DT. Looking for a R-by from Saravana and Ack from Greg. A R-by from Rafael would be great too. Rob