On Fri, Jun 22, 2018 at 5:49 AM <sean.wang@xxxxxxxxxxxx> wrote:
> From: Sean Wang <sean.wang@xxxxxxxxxxxx>
>
> When we are explicitly using GPIO hogging mechanism in the pinctrl node,
> such as:
>
> &pio {
> line_input {
> gpio-hog;
> gpios = <95 0>, <96 0>, <97 0>;
> input;
> };
> };
>
> A kernel panic happens at dereferencing a NULL pointer: In this case, the
> drvdata is still not setup properly yet when it is being accessed.
>
> A better solution for fixing up this issue should be we should obtain the
> private data from struct gpio_chip using a specific gpiochip_get_data
> instead of a generic dev_get_drvdata.
>
> [ 0.249424] Unable to handle kernel NULL pointer dereference at virtual
> address 000000c8
> [ 0.257818] Mem abort info:
> [ 0.260704] ESR = 0x96000005
> [ 0.263869] Exception class = DABT (current EL), IL = 32 bits
> [ 0.270011] SET = 0, FnV = 0
> [ 0.273167] EA = 0, S1PTW = 0
> [ 0.276421] Data abort info:
> [ 0.279398] ISV = 0, ISS = 0x00000005
> [ 0.283372] CM = 0, WnR = 0
> [ 0.286440] [00000000000000c8] user address but active_mm is swapper
> [ 0.293027] Internal error: Oops: 96000005 [#1] PREEMPT SMP
> [ 0.298795] Modules linked in:
> [ 0.301958] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.16.0-rc1+ #389
> [ 0.308716] Hardware name: MediaTek MT7622 RFB1 board (DT)
> [ 0.314396] pstate: 80000005 (Nzcv daif -PAN -UAO)
> [ 0.319362] pc : mtk_hw_pin_field_get+0x28/0x118
> [ 0.324140] lr : mtk_hw_set_value+0x30/0x104
> [ 0.328557] sp : ffffff800801b6d0
> [ 0.331983] x29: ffffff800801b6d0 x28: ffffff80086b7970
> [ 0.337484] x27: 0000000000000000 x26: ffffff80087b8000
> [ 0.342986] x25: 0000000000000000 x24: ffffffc00324c230
> [ 0.348487] x23: 0000000000000003 x22: 0000000000000000
> [ 0.353988] x21: ffffff80087b8000 x20: 0000000000000000
> [ 0.359489] x19: 0000000000000054 x18: 00000000fffff7c0
> [ 0.364990] x17: 0000000000006300 x16: 000000000000003f
> [ 0.370492] x15: 000000000000000e x14: ffffffffffffffff
> [ 0.375993] x13: 0000000000000000 x12: 0000000000000020
> [ 0.381494] x11: 0000000000000006 x10: 0101010101010101
> [ 0.386995] x9 : fffffffffffffffa x8 : 0000000000000007
> [ 0.392496] x7 : ffffff80085d63f8 x6 : 0000000000000003
> [ 0.397997] x5 : 0000000000000054 x4 : ffffffc0031eb800
> [ 0.403499] x3 : ffffff800801b728 x2 : 0000000000000003
> [ 0.409000] x1 : 0000000000000054 x0 : 0000000000000000
> [ 0.414502] Process swapper/0 (pid: 1, stack limit = 0x000000002a913c1c)
> [ 0.421441] Call trace:
> [ 0.423968] mtk_hw_pin_field_get+0x28/0x118
> [ 0.428387] mtk_hw_set_value+0x30/0x104
> [ 0.432445] mtk_gpio_set+0x20/0x28
> [ 0.436052] mtk_gpio_direction_output+0x18/0x30
> [ 0.440833] gpiod_direction_output_raw_commit+0x7c/0xa0
> [ 0.446333] gpiod_direction_output+0x104/0x114
> [ 0.451022] gpiod_configure_flags+0xbc/0xfc
> [ 0.455441] gpiod_hog+0x8c/0x140
> [ 0.458869] of_gpiochip_add+0x27c/0x2d4
> [ 0.462928] gpiochip_add_data_with_key+0x338/0x5f0
> [ 0.467976] mtk_pinctrl_probe+0x388/0x400
> [ 0.472217] platform_drv_probe+0x58/0xa4
> [ 0.476365] driver_probe_device+0x204/0x44c
> [ 0.480783] __device_attach_driver+0xac/0x108
> [ 0.485384] bus_for_each_drv+0x7c/0xac
> [ 0.489352] __device_attach+0xa0/0x144
> [ 0.493320] device_initial_probe+0x10/0x18
> [ 0.497647] bus_probe_device+0x2c/0x8c
> [ 0.501616] device_add+0x2f8/0x540
> [ 0.505226] of_device_add+0x3c/0x44
> [ 0.508925] of_platform_device_create_pdata+0x80/0xb8
> [ 0.514245] of_platform_bus_create+0x290/0x3e8
> [ 0.518933] of_platform_populate+0x78/0x100
> [ 0.523352] of_platform_default_populate+0x24/0x2c
> [ 0.528403] of_platform_default_populate_init+0x94/0xa4
> [ 0.533903] do_one_initcall+0x98/0x130
> [ 0.537874] kernel_init_freeable+0x13c/0x1d4
> [ 0.542385] kernel_init+0x10/0xf8
> [ 0.545903] ret_from_fork+0x10/0x18
> [ 0.549603] Code: 900020a1 f9400800 911dcc21 1400001f (f9406401)
> [ 0.555916] ---[ end trace de8c34787fdad3b3 ]---
> [ 0.560722] Kernel panic - not syncing: Attempted to kill init!
> exitcode=0x0000000b
> [ 0.560722]
> [ 0.570188] SMP: stopping secondary CPUs
> [ 0.574253] ---[ end Kernel panic - not syncing: Attempted to kill
> init! exitcode=0x0000000b
> [ 0.574253]
>
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: d6ed93551320 ("pinctrl: mediatek: add pinctrl driver for MT7622 SoC")
> Signed-off-by: Sean Wang <sean.wang@xxxxxxxxxxxx>
Patch applied for fixes.
Yours,
Linus Walleij
