Re: [PATCH] clk: Mark fwnodes when their clock provider is added
From: Geert Uytterhoeven <geert@linux-m68k.org>
Date: 2021-03-25 15:48:51
Also in:
linux-acpi, linux-clk, linux-devicetree, linux-pm, lkml
Hi Marek, On Thu, Mar 25, 2021 at 2:32 PM Marek Szyprowski [off-list ref] wrote:
On 10.02.2021 12:44, Tudor Ambarus wrote:quoted
This is a follow-up for: commit 3c9ea42802a1 ("clk: Mark fwnodes when their clock provider is added/removed") The above commit updated the deprecated of_clk_add_provider(), but missed to update the preferred of_clk_add_hw_provider(). Update it now. Signed-off-by: Tudor Ambarus <redacted>This patch, which landed in linux-next as commit 6579c8d97ad7 ("clk: Mark fwnodes when their clock provider is added") causes the following NULL pointer dereference on Raspberry Pi 3b+ boards: --->8--- raspberrypi-firmware soc:firmware: Attached to firmware from 2020-01-06T13:05:25 Unable to handle kernel NULL pointer dereference at virtual address 0000000000000050 Mem abort info: ESR = 0x96000004 EC = 0x25: DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 Data abort info: ISV = 0, ISS = 0x00000004 CM = 0, WnR = 0 [0000000000000050] user address but active_mm is swapper Internal error: Oops: 96000004 [#1] PREEMPT SMP Modules linked in: CPU: 0 PID: 10 Comm: kworker/0:1 Not tainted 5.12.0-rc4+ #2764 Hardware name: Raspberry Pi 3 Model B (DT) Workqueue: events deferred_probe_work_func pstate: 00000005 (nzcv daif -PAN -UAO -TCO BTYPE=--) pc : of_clk_add_hw_provider+0xac/0xe8 lr : of_clk_add_hw_provider+0x94/0xe8 sp : ffff8000130936b0 x29: ffff8000130936b0 x28: ffff800012494e04 x27: ffff00003b18cb05 x26: ffff00003aa5c010 x25: 0000000000000000 x24: 0000000000000000 x23: ffff00003aa1e380 x22: ffff8000106830d0 x21: ffff80001233f180 x20: 0000000000000018 x19: 0000000000000000 x18: ffff8000124d38b0 x17: 0000000000000013 x16: 0000000000000014 x15: ffff8000125758b0 x14: 00000000000184e0 x13: 000000000000292e x12: ffff80001258dd98 x11: 0000000000000001 x10: 0101010101010101 x9 : ffff80001233f288 x8 : 7f7f7f7f7f7f7f7f x7 : fefefefeff6c626f x6 : 5d636d8080808080 x5 : 00000000006d635d x4 : 0000000000000000 x3 : 0000000000000000 x2 : 540eb5edae191600 x1 : 0000000000000000 x0 : 0000000000000000 Call trace: of_clk_add_hw_provider+0xac/0xe8 devm_of_clk_add_hw_provider+0x5c/0xb8 raspberrypi_clk_probe+0x110/0x210 platform_probe+0x90/0xd8 really_probe+0x108/0x3c0 driver_probe_device+0x60/0xc0 __device_attach_driver+0x9c/0xd0 bus_for_each_drv+0x70/0xc8 __device_attach+0xec/0x150 device_initial_probe+0x10/0x18 bus_probe_device+0x94/0xa0 device_add+0x47c/0x780 platform_device_add+0x110/0x248 platform_device_register_full+0x120/0x150 rpi_firmware_probe+0x158/0x1f8
This patch mainly revealed that clk/bcm/clk-raspberrypi.c driver calls devm_of_clk_add_hw_provider(), with a device pointer, which has a NULL dev->of_node. I'm not sure if adding a check for a NULL np in of_clk_add_hw_provider() is a right fix, though.
raspberrypi_clk_probe():
/*
* We can be probed either through the an old-fashioned
* platform device registration or through a DT node that is a
* child of the firmware node. Handle both cases.
*/
So the real issue is rpi_register_clk_driver() creating a platform
device for the firmware clocks if they're missing in DT.
Then, the clock driver calls devm_of_clk_add_hw_provider(),
regardless of a DT node being present or not.
I'm wondering how power consumers are supposed to refer
to these firmware clocks, without a DT node?
quoted
--- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c@@ -4594,6 +4594,8 @@ int of_clk_add_hw_provider(struct device_node *np, if (ret < 0) of_clk_del_provider(np); + fwnode_dev_initialized(&np->fwnode, true); + return ret; } EXPORT_SYMBOL_GPL(of_clk_add_hw_provider);
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds