From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) (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 AB22413C689 for ; Mon, 6 Jan 2025 15:16:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.167.242.64 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736176598; cv=none; b=dqlBf15DIVNOSePx1zbQ5IP9sXXkA1LowiS5S+xIz8Bgbs0aVmkwM+xvNjP1aVPU+f61ZXlBBqhFCk3mAA2gpm/DKSrq0V1aloonog/jppPQ6B7q5Yg+E1dUgUGMpWZ/ZxBz64Bj2yuls53OYplRHIKc+oY/QGqx51W+D1K3Ink= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736176598; c=relaxed/simple; bh=DtPNeIfi4V0W0cwS02OqtYY/i4Np6KLqWDu8rB6A8BE=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=ubXvdiT5vQKn7lljybvyFgwm0vZU/WV8A6w32gnSkZcMzlILkB24SyyQcglqwXDJSnxQPqvNyjU7CZ3VNeRpEQnFi2DD/lQbxlCuMC+QLWPhNhRB/SkA+cPBQqXfx88GdMs5BcQfg8VyQZflgkMgu+tMtxnLmZQIwiK3oFndlnk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=ideasonboard.com; spf=pass smtp.mailfrom=ideasonboard.com; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b=nQFUith3; arc=none smtp.client-ip=213.167.242.64 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="nQFUith3" Received: from [192.168.88.20] (91-158-153-178.elisa-laajakaista.fi [91.158.153.178]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 375302A5; Mon, 6 Jan 2025 16:15:31 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1736176531; bh=DtPNeIfi4V0W0cwS02OqtYY/i4Np6KLqWDu8rB6A8BE=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=nQFUith3HpZWxxJK0hITV9/k+6B4H7S9tKWS5yQTwdhKpQw15Y519v7BS3S6OO1Pd Lr0Radk8IerpYpoNx+wnDyZy5OVdfjUnTzqh3OIKZYpF6QkfTLo1zHO3S9GSpvhznE AGjt2Zb7JDGYlOY3HqGOa2sYz8B7YjDNqRAc/u2s= Message-ID: <922c3edf-c52c-42ef-a096-e02f74e01f85@ideasonboard.com> Date: Mon, 6 Jan 2025 17:16:19 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3] driver core: fw_devlink: Stop trying to optimize cycle detection logic To: Saravana Kannan , Greg Kroah-Hartman , "Rafael J. Wysocki" Cc: Francesco , Geert Uytterhoeven , kernel-team@android.com, linux-kernel@vger.kernel.org, Jai Luthra References: <20241030171009.1853340-1-saravanak@google.com> Content-Language: en-US From: Tomi Valkeinen Autocrypt: addr=tomi.valkeinen@ideasonboard.com; keydata= xsFNBE6ms0cBEACyizowecZqXfMZtnBniOieTuFdErHAUyxVgtmr0f5ZfIi9Z4l+uUN4Zdw2 wCEZjx3o0Z34diXBaMRJ3rAk9yB90UJAnLtb8A97Oq64DskLF81GCYB2P1i0qrG7UjpASgCA Ru0lVvxsWyIwSfoYoLrazbT1wkWRs8YBkkXQFfL7Mn3ZMoGPcpfwYH9O7bV1NslbmyJzRCMO eYV258gjCcwYlrkyIratlHCek4GrwV8Z9NQcjD5iLzrONjfafrWPwj6yn2RlL0mQEwt1lOvn LnI7QRtB3zxA3yB+FLsT1hx0va6xCHpX3QO2gBsyHCyVafFMrg3c/7IIWkDLngJxFgz6DLiA G4ld1QK/jsYqfP2GIMH1mFdjY+iagG4DqOsjip479HCWAptpNxSOCL6z3qxCU8MCz8iNOtZk DYXQWVscM5qgYSn+fmMM2qN+eoWlnCGVURZZLDjg387S2E1jT/dNTOsM/IqQj+ZROUZuRcF7 0RTtuU5q1HnbRNwy+23xeoSGuwmLQ2UsUk7Q5CnrjYfiPo3wHze8avK95JBoSd+WIRmV3uoO rXCoYOIRlDhg9XJTrbnQ3Ot5zOa0Y9c4IpyAlut6mDtxtKXr4+8OzjSVFww7tIwadTK3wDQv Bus4jxHjS6dz1g2ypT65qnHen6mUUH63lhzewqO9peAHJ0SLrQARAQABzTBUb21pIFZhbGtl aW5lbiA8dG9taS52YWxrZWluZW5AaWRlYXNvbmJvYXJkLmNvbT7CwY4EEwEIADgWIQTEOAw+ ll79gQef86f6PaqMvJYe9QUCX/HruAIbAwULCQgHAgYVCgkICwIEFgIDAQIeAQIXgAAKCRD6 PaqMvJYe9WmFD/99NGoD5lBJhlFDHMZvO+Op8vCwnIRZdTsyrtGl72rVh9xRfcSgYPZUvBuT VDxE53mY9HaZyu1eGMccYRBaTLJSfCXl/g317CrMNdY0k40b9YeIX10feiRYEWoDIPQ3tMmA 0nHDygzcnuPiPT68JYZ6tUOvAt7r6OX/litM+m2/E9mtp8xCoWOo/kYO4mOAIoMNvLB8vufi uBB4e/AvAjtny4ScuNV5c5q8MkfNIiOyag9QCiQ/JfoAqzXRjVb4VZG72AKaElwipiKCWEcU R4+Bu5Qbaxj7Cd36M/bI54OrbWWETJkVVSV1i0tghCd6HHyquTdFl7wYcz6cL1hn/6byVnD+ sR3BLvSBHYp8WSwv0TCuf6tLiNgHAO1hWiQ1pOoXyMEsxZlgPXT+wb4dbNVunckwqFjGxRbl Rz7apFT/ZRwbazEzEzNyrBOfB55xdipG/2+SmFn0oMFqFOBEszXLQVslh64lI0CMJm2OYYe3 PxHqYaztyeXsx13Bfnq9+bUynAQ4uW1P5DJ3OIRZWKmbQd/Me3Fq6TU57LsvwRgE0Le9PFQs dcP2071rMTpqTUteEgODJS4VDf4lXJfY91u32BJkiqM7/62Cqatcz5UWWHq5xeF03MIUTqdE qHWk3RJEoWHWQRzQfcx6Fn2fDAUKhAddvoopfcjAHfpAWJ+ENc7BTQROprNHARAAx0aat8GU hsusCLc4MIxOQwidecCTRc9Dz/7U2goUwhw2O5j9TPqLtp57VITmHILnvZf6q3QAho2QMQyE DDvHubrdtEoqaaSKxKkFie1uhWNNvXPhwkKLYieyL9m2JdU+b88HaDnpzdyTTR4uH7wk0bBa KbTSgIFDDe5lXInypewPO30TmYNkFSexnnM3n1PBCqiJXsJahE4ZQ+WnV5FbPUj8T2zXS2xk 0LZ0+DwKmZ0ZDovvdEWRWrz3UzJ8DLHb7blPpGhmqj3ANXQXC7mb9qJ6J/VSl61GbxIO2Dwb xPNkHk8fwnxlUBCOyBti/uD2uSTgKHNdabhVm2dgFNVuS1y3bBHbI/qjC3J7rWE0WiaHWEqy UVPk8rsph4rqITsj2RiY70vEW0SKePrChvET7D8P1UPqmveBNNtSS7In+DdZ5kUqLV7rJnM9 /4cwy+uZUt8cuCZlcA5u8IsBCNJudxEqBG10GHg1B6h1RZIz9Q9XfiBdaqa5+CjyFs8ua01c 9HmyfkuhXG2OLjfQuK+Ygd56mV3lq0aFdwbaX16DG22c6flkkBSjyWXYepFtHz9KsBS0DaZb 4IkLmZwEXpZcIOQjQ71fqlpiXkXSIaQ6YMEs8WjBbpP81h7QxWIfWtp+VnwNGc6nq5IQDESH mvQcsFS7d3eGVI6eyjCFdcAO8eMAEQEAAcLBXwQYAQIACQUCTqazRwIbDAAKCRD6PaqMvJYe 9fA7EACS6exUedsBKmt4pT7nqXBcRsqm6YzT6DeCM8PWMTeaVGHiR4TnNFiT3otD5UpYQI7S suYxoTdHrrrBzdlKe5rUWpzoZkVK6p0s9OIvGzLT0lrb0HC9iNDWT3JgpYDnk4Z2mFi6tTbq xKMtpVFRA6FjviGDRsfkfoURZI51nf2RSAk/A8BEDDZ7lgJHskYoklSpwyrXhkp9FHGMaYII m9EKuUTX9JPDG2FTthCBrdsgWYPdJQvM+zscq09vFMQ9Fykbx5N8z/oFEUy3ACyPqW2oyfvU CH5WDpWBG0s5BALp1gBJPytIAd/pY/5ZdNoi0Cx3+Z7jaBFEyYJdWy1hGddpkgnMjyOfLI7B CFrdecTZbR5upjNSDvQ7RG85SnpYJTIin+SAUazAeA2nS6gTZzumgtdw8XmVXZwdBfF+ICof 92UkbYcYNbzWO/GHgsNT1WnM4sa9lwCSWH8Fw1o/3bX1VVPEsnESOfxkNdu+gAF5S6+I6n3a ueeIlwJl5CpT5l8RpoZXEOVtXYn8zzOJ7oGZYINRV9Pf8qKGLf3Dft7zKBP832I3PQjeok7F yjt+9S+KgSFSHP3Pa4E7lsSdWhSlHYNdG/czhoUkSCN09C0rEK93wxACx3vtxPLjXu6RptBw 3dRq7n+mQChEB1am0BueV1JZaBboIL0AGlSJkm23kw== In-Reply-To: <20241030171009.1853340-1-saravanak@google.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Hi Saravana, On 30/10/2024 19:10, Saravana Kannan wrote: > In attempting to optimize fw_devlink runtime, I introduced numerous cycle > detection bugs by foregoing cycle detection logic under specific > conditions. Each fix has further narrowed the conditions for optimization. > > It's time to give up on these optimization attempts and just run the cycle > detection logic every time fw_devlink tries to create a device link. > > The specific bug report that triggered this fix involved a supplier fwnode > that never gets a device created for it. Instead, the supplier fwnode is > represented by the device that corresponds to an ancestor fwnode. > > In this case, fw_devlink didn't do any cycle detection because the cycle > detection logic is only run when a device link is created between the > devices that correspond to the actual consumer and supplier fwnodes. > > With this change, fw_devlink will run cycle detection logic even when > creating SYNC_STATE_ONLY proxy device links from a device that is an > ancestor of a consumer fwnode. > > Reported-by: Tomi Valkeinen > Closes: https://lore.kernel.org/all/1a1ab663-d068-40fb-8c94-f0715403d276@ideasonboard.com/ > Fixes: 6442d79d880c ("driver core: fw_devlink: Improve detection of overlapping cycles") > Tested-by: Tomi Valkeinen > Signed-off-by: Saravana Kannan > --- > drivers/base/core.c | 55 ++++++++++++++++++++------------------------- > 1 file changed, 24 insertions(+), 31 deletions(-) > > Tomi, > > Thanks for all the testing and debugging help! And do use > post-init-providers even with this patch to improve ordering > enforcement. I probably should change the cycle log from info to warn in > a separate patch :) I've had this patch in one of my WIP branches for a while. Today I started debugging a kmemleak in the branch, which I thought was related to my changes. However, it ended up being this patch. One of the drivers touched in my WIP branch is drivers/media/i2c/ds90ub960.c. It does a i2c_new_client_device() and, at remove time, i2c_unregister_device(). Without this patch, with some debug prints, I see that the newly created i2c client has a kref count of 11, and when i2c_unregister_device() is called, I see kref dropping to 0 and i2c_client_dev_release() being called. With this patch, after i2c_new_client_device(), I see a kref of 16, and after i2c_unregister_device(), a kref of 5 (and i2c_client_dev_release() not called). So five new refs were added, and not released... Any thoughts? Tomi