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d=samsung.com; s=mail20170921; t=1772442486; bh=Ai2dOvOVRVVKUuflEzxhN3/sTsEiQpOTLnNvNlY3510=; h=Date:Subject:To:Cc:From:In-Reply-To:References:From; b=T7n1/OJYDFt+AI0ihYeP0Wlxo0IAQi1pePkAhHzBiQgRil4XI/6vQLyGcytm7OpTW ytBxDTBfxR2aer69NEO7bFKBBicb5mHxs6CNLt6iNvZ5oBgel6yVggl7rnce7umvdk RzAWwDOxPPMXjnZ//TFKH7tsQrdB4UN28+WvZFNM= Received: from eusmtip2.samsung.com (unknown [203.254.199.222]) by eucas1p1.samsung.com (KnoxPortal) with ESMTPA id 20260302090806eucas1p15686744857ca873135b57febcc3843fa~Y_wz3YHiq2681326813eucas1p1e; Mon, 2 Mar 2026 09:08:06 +0000 (GMT) Received: from [106.210.134.192] (unknown [106.210.134.192]) by eusmtip2.samsung.com (KnoxPortal) with ESMTPA id 20260302090806eusmtip2cef48814219a002b980f8498c00cbf1c~Y_wzkC9Ey1533915339eusmtip2Z; Mon, 2 Mar 2026 09:08:06 +0000 (GMT) Message-ID: Date: Mon, 2 Mar 2026 10:08:05 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Betterbird (Windows) Subject: Re: [PATCH] gpio: Fix lockdep warnings in gpiolib_{cdev,sysfs}_register() To: Tzung-Bi Shih , Bartosz Golaszewski , Linus Walleij Cc: linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org Content-Language: en-US From: Marek Szyprowski In-Reply-To: <20260228131430.102388-1-tzungbi@kernel.org> Content-Transfer-Encoding: 7bit X-CMS-MailID: 20260302090806eucas1p15686744857ca873135b57febcc3843fa X-Msg-Generator: CA Content-Type: text/plain; charset="utf-8" X-RootMTR: 20260228131459eucas1p1b5deb465c52d0990a6920b0d8981975f X-EPHeader: CA X-CMS-RootMailID: 20260228131459eucas1p1b5deb465c52d0990a6920b0d8981975f References: <20260228131430.102388-1-tzungbi@kernel.org> On 28.02.2026 14:14, Tzung-Bi Shih wrote: > A lockdep warning is reported in gpiolib-cdev driver: > > WARNING: drivers/gpio/gpiolib-cdev.c:2735 at > gpiolib_cdev_register+0x114/0x140, CPU#1: swapper/0/1 > Modules linked in: > CPU: 1 UID: 0 PID: 1 Comm: swapper/0 Not tainted > 7.0.0-rc1-next-20260227-00065-g6af4b9cfeded #12259 PREEMPT > Hardware name: Samsung Exynos (Flattened Device Tree) > Call trace: > unwind_backtrace from show_stack+0x10/0x14 > show_stack from dump_stack_lvl+0x68/0x88 > dump_stack_lvl from __warn+0x94/0x210 > __warn from warn_slowpath_fmt+0x1b0/0x1bc > warn_slowpath_fmt from gpiolib_cdev_register+0x114/0x140 > gpiolib_cdev_register from gpiochip_setup_dev+0x4c/0xd0 > gpiochip_setup_dev from gpiochip_add_data_with_key+0x960/0xad4 > gpiochip_add_data_with_key from devm_gpiochip_add_data_with_key+0x20/0x5c > > This is because the SRCU wasn't held in gpiolib_cdev_register() when the > caller is from gpiochip_add_data_with_key() instead of > gpiochip_setup_devs(). gpiochip_sysfs_register() shares the similar > concern. > > Given that both gpiolib_cdev_register() and gpiochip_sysfs_register() > are only called from gpiolib but no external users. Remove the lockdep > checks to fix the warnings. > > Reported-by: Marek Szyprowski > Closes: https://lore.kernel.org/all/506ce9b3-d492-4fce-9d02-330e411911e2@samsung.com/ > Fixes: cf674f1a0c98 ("gpio: Ensure struct gpio_chip for gpiochip_setup_dev()") > Signed-off-by: Tzung-Bi Shih Tested-by: Marek Szyprowski > --- > drivers/gpio/gpiolib-cdev.c | 2 -- > drivers/gpio/gpiolib-sysfs.c | 2 -- > 2 files changed, 4 deletions(-) > > diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c > index 7ebdb4993a74..f36b7c06996d 100644 > --- a/drivers/gpio/gpiolib-cdev.c > +++ b/drivers/gpio/gpiolib-cdev.c > @@ -2732,8 +2732,6 @@ int gpiolib_cdev_register(struct gpio_chip *gc, dev_t devt) > struct gpio_device *gdev = gc->gpiodev; > int ret; > > - lockdep_assert_held(&gdev->srcu); > - > cdev_init(&gdev->chrdev, &gpio_fileops); > gdev->chrdev.owner = THIS_MODULE; > gdev->dev.devt = MKDEV(MAJOR(devt), gdev->id); > diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c > index 748a3eb1bf35..fc06b0c2881b 100644 > --- a/drivers/gpio/gpiolib-sysfs.c > +++ b/drivers/gpio/gpiolib-sysfs.c > @@ -990,8 +990,6 @@ int gpiochip_sysfs_register(struct gpio_chip *gc) > struct device *parent; > int err; > > - lockdep_assert_held(&gdev->srcu); > - > /* > * Many systems add gpio chips for SOC support very early, > * before driver model support is available. In those cases we Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland