From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [134.134.136.65]) (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 B5350182A3 for ; Wed, 3 Jan 2024 08:20:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="FDRUBsCK" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1704270028; x=1735806028; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=0Ul4OlGMi2BplcTsZp5Kk6kGh3sCmw9tmO1+Lmr7FJM=; b=FDRUBsCKhDMTybReWXmttXSqdzqlfeUwscNBw9dOgizvQoZSPp34Akag hiQyaEiYQvOvc5GYTqqQ5NK0omuai2U9bFGRrdHWz+MvCMrav13iijf24 1vq1lu/2kRRwE0KmaHzyvdYq7DkPj5hLa387qswA6u8e1cccP6YdVzlTP BRYJDK4h6UNiMPHzLiUe5YNFcuMJzCj//WUiaGXt+Jt7LiTnZiY29PdnH ee+tIujiOh6wHNCvJVrqbccmh7qzh/hHxCUwWJRdT/rjOAPnt1ygLOKBs bqKT1Sjhg53m3DQBBcI+5v0654ZpoC5D+Gi1CsnTnKmfX11ad6QoP5YhF g==; X-IronPort-AV: E=McAfee;i="6600,9927,10941"; a="400789293" X-IronPort-AV: E=Sophos;i="6.04,327,1695711600"; d="scan'208";a="400789293" Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Jan 2024 00:20:28 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10941"; a="779928866" X-IronPort-AV: E=Sophos;i="6.04,327,1695711600"; d="scan'208";a="779928866" Received: from sgruszka-mobl.ger.corp.intel.com (HELO localhost) ([10.252.51.153]) by orsmga002-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Jan 2024 00:20:25 -0800 Date: Wed, 3 Jan 2024 09:20:23 +0100 From: Stanislaw Gruszka To: Heiner Kallweit Cc: Johannes Berg , Przemek Kitszel , netdev@vger.kernel.org, Marc MERLIN , Jesse Brandeburg , Tony Nguyen , intel-wired-lan@lists.osuosl.org, Aleksandr Loktionov Subject: Re: [RFC PATCH] net: ethtool: do runtime PM outside RTNL Message-ID: References: <20231204200710.40c291e60cea.I2deb5804ef1739a2af307283d320ef7d82456494@changeid> <709eff7500f2da223df9905ce49c026a881cb0e0.camel@sipsolutions.net> <3e7ae1f5-77e3-a561-2d6b-377026b1fd26@intel.com> <64684afc-3dbb-453e-9c90-bf2a86e70c50@gmail.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <64684afc-3dbb-453e-9c90-bf2a86e70c50@gmail.com> On Wed, Dec 06, 2023 at 12:59:09PM +0100, Heiner Kallweit wrote: > On 06.12.2023 10:37, Johannes Berg wrote: > > On Wed, 2023-12-06 at 09:46 +0100, Przemek Kitszel wrote: > >> > >> That sounds right too; one could argue if your fix is orthogonal to that > >> or not. I would say that your fix makes core net code more robust > >> against drivers from past millennia. :) > >> igc folks are notified, no idea how much time it would take to propose > >> a fix. > > > > Maybe it should be on whoever added runtime pm to ethtool ;-) > > > > Heiner, the igc driver was already doing this when you added > > pm_runtime_get_sync() ops, was there a discussion at the time, or just > > missed? > > > I think it went unnoticed at that time that igc is acquiring RTNL > in runtime-resume. I'm just astonished that this pops up only now, > considering that the change was done more than 2 yrs ago. PM runtime is disabled by default for igc (driver do not call pm_runtime_allow()). It has to be enabled explicitly by user write to pci sysfs power/control file. And after that link up/down or ethtool has to be used to trigger this deadlock, so quite unlikely scenario. Is possible though, that some power saving daemon start enabling pm runtime for devices, so that why issue become visible. Regards Stanislaw