From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.14]) (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 7B8361FDA61; Wed, 7 May 2025 15:15:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.14 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746630950; cv=none; b=Tz2+7UTDWpPkfMG/2V42hWhkwjPExzU2316FSbP1/hZeJu0a5NWUuli9zgetclUP4tTUAnWhD8PzYwzmvSroNUm6JDXvjbkcBS/aHoqfl4MrPN7pAMn0PsseLqWm/yeKrgv1Qa9KkBIAeGt6abzRaf52wwiGCXY6ruwbeTnLfmE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746630950; c=relaxed/simple; bh=yO+CLLJleqQCOJ1P7Cw9+o2RW0jsGz/mD7j9rcWCyFk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=erYOFfOwJLpeg7FTnqWPECC9AJwDqdCRYOmCCW7hBeCQxQH8J+edYGm2+NQPo8qkSQBFIZEXWaB2B6+qJWhwnDwRM41NTmoB2y3gypKkPf0hXtsJ9YTO+5q/eNWS9TMjGEQkvv1Lo5lQ7SRI2Nbg2/v7NtUT8Mg5gWeKcdBu+ik= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=none smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=Yy44zIO9; arc=none smtp.client-ip=192.198.163.14 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="Yy44zIO9" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1746630949; x=1778166949; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=yO+CLLJleqQCOJ1P7Cw9+o2RW0jsGz/mD7j9rcWCyFk=; b=Yy44zIO9S8es7yCDyOqM/+Bmx2BiBh12nDbqIb322z+UvoZMnQk0Ifcx LH/HvLGt8VzdfLnnCoqPIb3+qRlGR0FM3nw/Ski5f7aXWLR7OhMmpZa28 FqtKkwOckmSWKXK+tO/+j5tHoA32iSJuVO43Q67UhSVLNCunj4ZS31U8A c8GsWCWUCceNjYyguH+Fi+GsdG54u3Ls3RF4Lj2H2n+ldMArYk8u/wKxk +DRph4ibvsJy5fKTa/1PjtwJGr8TI14eoS/cEuiZe5t8xc1wVyQh006VO e0EUQEhy7Qb1TUs4bTWTotfZ4jVoCr8I7bEzGQV+mdrs9kZM4G+a1YW43 Q==; X-CSE-ConnectionGUID: mG/VuD5BThS7DPpV4/tNQw== X-CSE-MsgGUID: tUMIjCwfSaqpZZ5qtc3QoQ== X-IronPort-AV: E=McAfee;i="6700,10204,11426"; a="48480563" X-IronPort-AV: E=Sophos;i="6.15,269,1739865600"; d="scan'208";a="48480563" Received: from orviesa006.jf.intel.com ([10.64.159.146]) by fmvoesa108.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 May 2025 08:15:47 -0700 X-CSE-ConnectionGUID: OcLle1K7QPmnpTiiYJJHXQ== X-CSE-MsgGUID: jQAKSpd0R9iEv0m2vr7j7w== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.15,269,1739865600"; d="scan'208";a="135906012" Received: from smile.fi.intel.com ([10.237.72.55]) by orviesa006.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 May 2025 08:15:38 -0700 Received: from andy by smile.fi.intel.com with local (Exim 4.98.2) (envelope-from ) id 1uCgUg-00000003lXp-2GW9; Wed, 07 May 2025 18:15:34 +0300 Date: Wed, 7 May 2025 18:15:34 +0300 From: Andy Shevchenko To: Herve Codina Cc: Andrew Lunn , Greg Kroah-Hartman , "Rafael J. Wysocki" , Danilo Krummrich , Shawn Guo , Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam , Michael Turquette , Stephen Boyd , Andi Shyti , Wolfram Sang , Peter Rosin , Derek Kiernan , Dragan Cvetic , Arnd Bergmann , Rob Herring , Saravana Kannan , Bjorn Helgaas , Mark Brown , Len Brown , Daniel Scally , Heikki Krogerus , Sakari Ailus , Wolfram Sang , Geert Uytterhoeven , linux-kernel@vger.kernel.org, imx@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-clk@vger.kernel.org, linux-i2c@vger.kernel.org, devicetree@vger.kernel.org, linux-pci@vger.kernel.org, linux-spi@vger.kernel.org, linux-acpi@vger.kernel.org, Allan Nielsen , Horatiu Vultur , Steen Hegelund , Luca Ceresoli , Thomas Petazzoni Subject: Re: [PATCH v2 04/26] driver core: Avoid warning when removing a device while its supplier is unbinding Message-ID: References: <20250507071315.394857-1-herve.codina@bootlin.com> <20250507071315.394857-5-herve.codina@bootlin.com> Precedence: bulk X-Mailing-List: linux-acpi@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: <20250507071315.394857-5-herve.codina@bootlin.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo On Wed, May 07, 2025 at 09:12:46AM +0200, Herve Codina wrote: > During driver removal, the following warning can appear: > WARNING: CPU: 1 PID: 139 at drivers/base/core.c:1497 __device_links_no_driver+0xcc/0xfc > ... > Call trace: > __device_links_no_driver+0xcc/0xfc (P) > device_links_driver_cleanup+0xa8/0xf0 > device_release_driver_internal+0x208/0x23c > device_links_unbind_consumers+0xe0/0x108 > device_release_driver_internal+0xec/0x23c > device_links_unbind_consumers+0xe0/0x108 > device_release_driver_internal+0xec/0x23c > device_links_unbind_consumers+0xe0/0x108 > device_release_driver_internal+0xec/0x23c > driver_detach+0xa0/0x12c > bus_remove_driver+0x6c/0xbc > driver_unregister+0x30/0x60 > pci_unregister_driver+0x20/0x9c > lan966x_pci_driver_exit+0x18/0xa90 [lan966x_pci] > > This warning is triggered when a consumer is removed because the links > status of its supplier is not DL_DEV_DRIVER_BOUND and the link flag > DL_FLAG_SYNC_STATE_ONLY is not set. > > The topology in terms of consumers/suppliers used was the following > (consumer ---> supplier): > > i2c -----------> OIC ----> PCI device > | ^ > | | > +---> pinctrl ---+ > > When the PCI device is removed, the OIC (interrupt controller) has to be > removed. In order to remove the OIC, pinctrl and i2c need to be removed > and to remove pinctrl, i2c need to be removed. The removal order is: > 1) i2c > 2) pinctrl > 3) OIC > 4) PCI device > > In details, the removal sequence is the following (with 0000:01:00.0 the > PCI device): > driver_detach: call device_release_driver_internal(0000:01:00.0)... > device_links_busy(0000:01:00.0): > links->status = DL_DEV_UNBINDING > device_links_unbind_consumers(0000:01:00.0): > 0000:01:00.0--oic link->status = DL_STATE_SUPPLIER_UNBIND > call device_release_driver_internal(oic)... > device_links_busy(oic): > links->status = DL_DEV_UNBINDING > device_links_unbind_consumers(oic): > oic--pinctrl link->status = DL_STATE_SUPPLIER_UNBIND > call device_release_driver_internal(pinctrl)... > device_links_busy(pinctrl): > links->status = DL_DEV_UNBINDING > device_links_unbind_consumers(pinctrl): > pinctrl--i2c link->status = DL_STATE_SUPPLIER_UNBIND > call device_release_driver_internal(i2c)... > device_links_busy(i2c): links->status = DL_DEV_UNBINDING > __device_links_no_driver(i2c)... > pinctrl--i2c link->status is DL_STATE_SUPPLIER_UNBIND > oic--i2c link->status is DL_STATE_ACTIVE > oic--i2c link->supplier->links.status is DL_DEV_UNBINDING > > The warning is triggered by the i2c removal because the OIC (supplier) > links status is not DL_DEV_DRIVER_BOUND. Its links status is indeed set > to DL_DEV_UNBINDING. > > It is perfectly legit to have the links status set to DL_DEV_UNBINDING > in that case. Indeed we had started to unbind the OIC which triggered > the consumer unbinding and didn't finish yet when the i2c is unbound. > > Avoid the warning when the supplier links status is set to > DL_DEV_UNBINDING and thus support this removal sequence without any > warnings. ... > if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) { > WRITE_ONCE(link->status, DL_STATE_AVAILABLE); > } else { > - WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY)); > + if (link->supplier->links.status != DL_DEV_UNBINDING) > + WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY)); Why not WARN_ON(link->supplier->links.status != DL_DEV_UNBINDING && !(link->flags & DL_FLAG_SYNC_STATE_ONLY)); > WRITE_ONCE(link->status, DL_STATE_DORMANT); > } -- With Best Regards, Andy Shevchenko