From patchwork Wed May 7 07:12:46 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Herve Codina X-Patchwork-Id: 888195 Received: from relay8-d.mail.gandi.net (relay8-d.mail.gandi.net [217.70.183.201]) (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 0899921D5B6; Wed, 7 May 2025 07:13:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.70.183.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746602017; cv=none; b=BwyEBk2Sa98hCLtmbd/tD4mwMNUo0Ko3cNlZW5gP0Q+boZA9aHT1Cnf5VJkm2/mWytMjiyaBgVom96EIr0q0Hhi/3bKy/ROV8zCo3zFIJNIb28dmJWcHKmzjoLIop+pENa4xH19CzPk7Q5zQ/qZSzdQl2shAl8KdP0+m5asYvUQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746602017; c=relaxed/simple; bh=/KlJMDRmtsNfGVkxPtdv7OTdn9lYP2ciCr/3JPzB5fw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=NZC4IWx2qz29dahisaeEmayeTuTyCDRhmakFjYPVdbz32rqLudabQny7u9Xu4IHLT/KXPq4bkte2umFhp96PSQGNRHaQU3QINhGYRAUSMpgkace7k3E7ERtEIx6jXWjKw0fuFG1xTdj8zmWt5fqUHDBDsaXN6FQ4CNGHRme/G98= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com; spf=pass smtp.mailfrom=bootlin.com; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b=SdWV2QMX; arc=none smtp.client-ip=217.70.183.201 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=bootlin.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b="SdWV2QMX" Received: by mail.gandi.net (Postfix) with ESMTPA id 8ECD743B5E; Wed, 7 May 2025 07:13:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1746602013; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=itxan9EuG0FuUpqxKlqCP8iOs9iWcsyZKP4fqZ5Hxr0=; b=SdWV2QMXpGhZJK6TzbcR016k5y/LspDiqBraCC6VrAY8thDpkRIR6ZeEMbXycPhF1DcN70 YwcCzRB6UlEUgP4t8CB1SrIRCWWsy6kC+KWHtMyuPrlh7+41JixOEVTrCOUmfvPR1tzRz0 nDupRUP685f04bv/AFIMR5gHiN+MsTbqgp2u9X1BYIPy/mxrt0dGy6OPIb8Gp3JmXSPIDx affEn+cQhM0VAo3FQ8tl40ia6yCJKz2/ot3V19icUCrvYJYnmp49Eu0n5Xj5mfuCSK8+gN 6PfRra8pj3BZyoC1tAaA/ObN4rYX8PE2eOggHtGYAp2DEgE0T5uQxbFdRmjB4w== From: Herve Codina To: 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 , Herve Codina , Rob Herring , Saravana Kannan , Bjorn Helgaas , Mark Brown , Len Brown , Andy Shevchenko , Daniel Scally , Heikki Krogerus , Sakari Ailus Cc: 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: [PATCH v2 04/26] driver core: Avoid warning when removing a device while its supplier is unbinding Date: Wed, 7 May 2025 09:12:46 +0200 Message-ID: <20250507071315.394857-5-herve.codina@bootlin.com> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250507071315.394857-1-herve.codina@bootlin.com> References: <20250507071315.394857-1-herve.codina@bootlin.com> Precedence: bulk X-Mailing-List: linux-acpi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-GND-State: clean X-GND-Score: -100 X-GND-Cause: gggruggvucftvghtrhhoucdtuddrgeefvddrtddtgddvkeeivdefucetufdoteggodetrfdotffvucfrrhhofhhilhgvmecuifetpfffkfdpucggtfgfnhhsuhgsshgtrhhisggvnecuuegrihhlohhuthemuceftddunecusecvtfgvtghiphhivghnthhsucdlqddutddtmdenucfjughrpefhvfevufffkffojghfggfgsedtkeertdertddtnecuhfhrohhmpefjvghrvhgvucevohguihhnrgcuoehhvghrvhgvrdgtohguihhnrgessghoohhtlhhinhdrtghomheqnecuggftrfgrthhtvghrnhepheffiefgjeeuleeuueffleeufefglefhjefhheeigedukeetieeltddthfffkeffnecukfhppeeltddrkeelrdduieefrdduvdejnecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehinhgvthepledtrdekledrudeifedruddvjedphhgvlhhopehlohgtrghlhhhoshhtrdhlohgtrghlughomhgrihhnpdhmrghilhhfrhhomhephhgvrhhvvgdrtghoughinhgrsegsohhothhlihhnrdgtohhmpdhnsggprhgtphhtthhopeegvddprhgtphhtthhopegrnhgurhgvfieslhhunhhnrdgthhdprhgtphhtthhopehgrhgvghhkhheslhhinhhugihfohhunhgurghtihhonhdrohhrghdprhgtphhtthhopehrrghfrggvlheskhgvrhhnvghlrdhorhhgpdhrtghpthhtohepuggrkhhrsehkvghrnhgvlhdrohhrghdprhgtphhtthhopehshhgrfihnghhuoheskhgvrhhnvghlrdhorhhgpdhrtghpthhtohepshdrh hgruhgvrhesphgvnhhguhhtrhhonhhigidruggvpdhrtghpthhtohepkhgvrhhnvghlsehpvghnghhuthhrohhnihigrdguvgdprhgtphhtthhopehfvghsthgvvhgrmhesghhmrghilhdrtghomh X-GND-Sasl: herve.codina@bootlin.com 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. Signed-off-by: Herve Codina --- drivers/base/core.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/base/core.c b/drivers/base/core.c index 5d6687f38d00..b44f9d371d47 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -1494,7 +1494,8 @@ static void __device_links_no_driver(struct device *dev) 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)); WRITE_ONCE(link->status, DL_STATE_DORMANT); } }