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 1D748158866 for ; Fri, 6 Sep 2024 11:14:37 +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=1725621280; cv=none; b=BIgQ8qq6tYMz7xRUoh9BQd137qGJDcjLExWHPv4WbinY+op4zX6Bp2cyXC7v2qEHXR4/uv9f3NDF1q+rqajLn66QGPFoX6uL1JUmo0jEuD36n1CsnqOfK67I0a6khIwQEVnS6b9vMUPs9nAPGAkxhmixQW9NMefMTf9ypQyYxDg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725621280; c=relaxed/simple; bh=eAIFhx0FH5JXpanUhnpZlqkZc8Pc3ok7YhqXJ4+agok=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=aLzWGKr93/73VWDXv2NGtxQkXM6M4BILHXHNtg1rtitM+SGL25dprrwPS7Van7f72kgmI7uTtRXIeMAHnLqx4hlFlpUr6xgrJ3pxwxSk1VRifLLmDLfXIfaY4JxDuHcyOAVBB9si2ai0DK8fa1bGKlPTrJoZryQsi9bASfS3x+w= 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=PDeudHnr; 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="PDeudHnr" Received: from [192.168.88.20] (91-156-87-48.elisa-laajakaista.fi [91.156.87.48]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 6399E45B; Fri, 6 Sep 2024 13:13:22 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1725621202; bh=eAIFhx0FH5JXpanUhnpZlqkZc8Pc3ok7YhqXJ4+agok=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=PDeudHnr/T1g++vH1/TFcvCObwqH8M1E3MyY3JRYo4Iyi272gDbmUVHiB92Fhyfyd HL+eFNI/tNxtOgDTnHYO1DmGfzKyli5P7U9X71zd3CmOEujTgcYT09CllNflav3e2+ wj/wszG2R5SEm5DZPx8NeR78cpO/XeRlSLRE3PVo= Message-ID: Date: Fri, 6 Sep 2024 14:14:33 +0300 Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: Race in rcar-v4l2.c To: =?UTF-8?Q?Niklas_S=C3=B6derlund?= Cc: linux-media@vger.kernel.org References: <20240906101446.GS3708622@fsdn.se> 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: <20240906101446.GS3708622@fsdn.se> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Hi Niklas, On 06/09/2024 13:14, Niklas Söderlund wrote: > Hi Tomi, > > Thanks for your report. > > I have an on-going series trying to clean this all up [1]. The one > change in the v4l-async core I proposed was however rejected and I have > yet to circle back to figure out a different solution. > > Could you give it a try and see if it also solves this issue? > > 1. [PATCH 0/6] media: rcar-vin: Make use of multiple connections in v4l-async > https://lore.kernel.org/linux-renesas-soc/20240129202254.1126012-1-niklas.soderlund+renesas@ragnatech.se/ The compilation fails (broken in media: rcar-vin: Simplify remote source type detection) with: drivers/media/platform/renesas/rcar-vin/rcar-dma.c:767:24: error: ‘struct rvin_dev’ has no member named ‘is_csi’ If I hack past that, I don't see the warnings anymore. But if I'm not mistaken, rvin_release() is not called at all anymore. I can also see plenty of leaks with kmemleak. Those seem to originate from max96712, but... I don't see max96712's remove() getting called either when I remove the module. I'm testing on Renesas' whitehawk board, with max96712 TPG. If you have that board, and want to try module loading & unloading, you also need to fix the max96712 remove function: - struct max96712_priv *priv = i2c_get_clientdata(client); + struct v4l2_subdev *sd = i2c_get_clientdata(client); + struct max96712_priv *priv = v4l2_get_subdevdata(sd); Tomi > On 2024-09-06 12:57:50 +0300, Tomi Valkeinen wrote: >> Hi Niklas, >> >> There seems to be a race in rcar-v4l2.c, causing >> WARN_ON(entity->use_count < 0) in pipeline_pm_power_one(). >> >> If my understanding is correct, the VIN v4l2 nodes are being created >> (rvin_v4l2_register), meaning they are userspace accessible, but the media >> pipeline as a whole is not ready yet (e.g. media links). >> >> So what happens is that after some video nodes have been created, the >> userspace opens them (I think it's udevd checking the new device nodes), >> causing rvin_open(). rvin_open() goes through the media graph and does some >> PM enabling (I'm not familiar with the legacy v4l2_pipeline_pm_get()). >> However, as the links are not there, it doesn't really enable much at all. >> >> Then the driver goes forward and finishes with the media graph. >> >> Then the userspace closes the opened video nodes, rvin_release() gets called >> and it goes through the media graph, which now contains all the entities, >> and powers them down. As the entities were never powered up, we hit the >> use_count warning. >> >> This happens quite often to me when loading the modules, but I think it can >> be made to happen more often by adding msleep(1000) to the beginning of >> rvin_release(), thus ensuring that the graph setup is finished before the >> rvin_release() proceeds (and hoping that the graph setup was not ready when >> rvin_open() was called). >> >> Tomi >> >