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b=rsBM2xylS0BiWLUWv1nP+zNOLjC/BK5r0XsKkZJ0ptRPDi47AEUhvI1YI6dp8Id++TqltMMBKVl5W2kox8ixyDHLIfQs9Ar17xWlD6i4//pe2LJInxlSl2mKYBtbw0YazlXsJzJ6rbwyPbzsVvAi798RdMXmLJwI/gj/sCotA7TQb9yQi84okn6pL87uGDvsgnIyQ3+/EgwJvCPGVE/wHgAmHqb4oe8cMYxYeZa5hKR//QscpA9oDPiryz0Fz8sn1y3R7Or94s0QiKSPNkvsrM9eNsO8yZ4ClfI4pAGcAM8U8oA5pBs3+J8JPcoxptFL0/DvPSZLkdHde7GNfbgIaw== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from DS2PR12MB9750.namprd12.prod.outlook.com (2603:10b6:8:2b0::12) by CH2PR12MB4326.namprd12.prod.outlook.com (2603:10b6:610:af::11) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9700.12; Wed, 11 Mar 2026 18:38:23 +0000 Received: from DS2PR12MB9750.namprd12.prod.outlook.com ([fe80::56a8:d6bf:e24c:b391]) by DS2PR12MB9750.namprd12.prod.outlook.com ([fe80::56a8:d6bf:e24c:b391%5]) with mapi id 15.20.9723.000; Wed, 11 Mar 2026 18:38:23 +0000 Message-ID: <921ba8ce-b18e-4a99-966d-c763d22081e2@nvidia.com> Date: Wed, 11 Mar 2026 18:38:16 +0000 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 03/10] gpiolib: implement low-level, shared GPIO support To: Bartosz Golaszewski , Kees Cook , Mika Westerberg , Dmitry Torokhov , Andrew Morton , Linus Walleij , Manivannan Sadhasivam , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Saravana Kannan , Greg Kroah-Hartman , Andy Shevchenko , Catalin Marinas , Will Deacon , Srinivas Kandagatla , Liam Girdwood , Mark Brown , Jaroslav Kysela , Takashi Iwai , Alexey Klimov , Bjorn Andersson , Konrad Dybcio Cc: linux-hardening@vger.kernel.org, linux-kernel@vger.kernel.org, linux-gpio@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-sound@vger.kernel.org, linux-arm-msm@vger.kernel.org, Bartosz Golaszewski , "linux-tegra@vger.kernel.org" References: <20251112-gpio-shared-v4-0-b51f97b1abd8@linaro.org> <20251112-gpio-shared-v4-3-b51f97b1abd8@linaro.org> From: Jon Hunter Content-Language: en-US In-Reply-To: <20251112-gpio-shared-v4-3-b51f97b1abd8@linaro.org> Content-Type: text/plain; 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When the GPIO chip exposing shared > lines is registered, the shared GPIO descriptors it exposes are marked > as shared and virtual "proxy" devices that mediate access to the shared > lines are created. When a consumer of a shared GPIO looks it up, its > fwnode lookup is redirected to a just-in-time machine lookup that points > to this proxy device. > > This code can be compiled out on platforms which don't use shared GPIOs. > > Reviewed-by: Linus Walleij > Acked-by: Linus Walleij > Signed-off-by: Bartosz Golaszewski I have observed a crash on one of our boards with Linux v6.19 and I was able to reproduce the same crash on a recent -next. The crash log I see is ... Unable to handle kernel paging request at virtual address f0f21322a6ad56c5 Mem abort info: ESR = 0x0000000096000004 EC = 0x25: DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 FSC = 0x04: level 0 translation fault Data abort info: ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000 CM = 0, WnR = 0, TnD = 0, TagAccess = 0 GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 [f0f21322a6ad56c5] address between user and kernel address ranges Internal error: Oops: 0000000096000004 [#1] SMP Modules linked in: CPU: 9 UID: 0 PID: 95 Comm: kworker/u51:4 Not tainted 7.0.0-rc3-next-20260309-00004-g34a79c0d58ea-dirty #13 PREEMPT Hardware name: NVIDIA NVIDIA Jetson AGX Orin Developer Kit/Jetson, BIOS buildbrain-gcid-42974706 11/20/2025 Workqueue: events_unbound deferred_probe_work_func pstate: 20400009 (nzCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : __srcu_read_lock+0x18/0x84 lr : gpiod_request_commit+0x30/0x174 sp : ffff8000843fb8d0 x29: ffff8000843fb8d0 x28: ffff800081e12000 x27: 0000000000000200 x26: 00000000000000b9 x25: ffff000080ad92d8 x24: ffff000085cdd940 x23: ffff800081e12cc0 x22: f0f21322a6ad56c5 x21: ffff800082df0528 x20: f0f21322a6ad5295 x19: f0f21322a6ad56c5 x18: 00000000ffffffff x17: ffff000080c04d80 x16: 1fffe000101809a1 x15: ffff8000843fb530 x14: ffff000080b17192 x13: ffff000080b1718e x12: ffff0007a1e468b8 x11: ffff80008199ccf0 x10: 0000000000000000 x9 : 0000000000000000 x8 : 1fffe0001014ec41 x7 : 0000000000000fff x6 : 0000000000000fff x5 : ffff800082df0538 x4 : ffff000081011410 x3 : ffff0000825b82b0 x2 : ffff0000816daf40 x1 : ffff800081e12cc0 x0 : f0f21322a6ad56c5 Call trace: __srcu_read_lock+0x18/0x84 (P) gpiod_request_commit+0x30/0x174 gpio_device_setup_shared+0x144/0x254 gpiochip_add_data_with_key+0xc38/0xeec devm_gpiochip_add_data_with_key+0x30/0x7c tegra186_gpio_probe+0x5cc/0x844 platform_probe+0x5c/0x98 really_probe+0xbc/0x2a8 __driver_probe_device+0x78/0x12c driver_probe_device+0x3c/0x15c __device_attach_driver+0xb8/0x134 bus_for_each_drv+0x84/0xe0 __device_attach+0x9c/0x188 device_initial_probe+0x50/0x54 bus_probe_device+0x38/0xa4 deferred_probe_work_func+0x88/0xc0 process_one_work+0x154/0x294 worker_thread+0x184/0x304 kthread+0x118/0x124 ret_from_fork+0x10/0x20 Code: d5384102 910003fd a90153f3 aa0003f3 (f9400014) ---[ end trace 0000000000000000 ]--- On Tegra234, the main gpio controller has a total of 164 GPIOs (see the tegra234_main_ports in drivers/gpio/gpio-tegra186.c). The GPIOs are assigned a index by the kernel from 0-163, but these GPIOs are not contiguous with respect to the device-tree specifier. For example, in device-tree, if I have a shared-gpio with the following specifier ... gpios = <&gpio TEGRA234_MAIN_GPIO(AF, 1) GPIO_ACTIVE_LOW>; The macro TEGRA234_MAIN_GPIO(AF, 1) evaluates to (23 * 8) + 1 = 185. This is greater than 164 and this is causing the above crash because 'entry->offset' in gpio_device_setup_shared() is greater than 'gdev->ngpio' and this causes us to access invalid memory. This is what I have been able to determine so far and wanted to get your inputs. Thanks Jon -- nvpublic