HELP:Kernel Panic after enabling IIO-HWMON driver in DTS

[Joel Stanley]

On Thu, 20 Dec 2018 at 16:14, A, Maheswari <maheswari.a at atos.net> wrote:
>
> Hi,
>
>
>
> I have already enabled IIO-HWMON and ASPEED_ADC drivers in linux configuration file.
>
>
>
> Included  changes in my platform DTS file.

Which DTS file did you make these changes to? Can you please point me
to the rest of the file.

What is the git SHA of the kernel commit you based your work on?

>     iio-hwmon {
>
> +                compatible = "iio-hwmon";
>
> +                io-channels = <&adc 12>;
>
> +        };
>
> @@ -334,3 +339,8 @@
>
> +&adc
>
> +{
>
> +       status = "okay";
>
> +};
>
>
>
> We are getting the below Kernel panic after this IIO-HWMON driver changes in DTS file.
>
>
>
> Other platform are using this iio-hwmon driver. Please let us know if anyone faced this same issue.
>
>
>
>
>
> [    3.761575] ==== 1. IIO_HWMON Probe === [    3.765477] Unable to handle kernel paging request at virtual address fffffdfb [    3.772710] pgd = f5dd9e82 [    3.775426] [fffffdfb] *pgd=9effd861, *pte=00000000, *ppte=00000000 [    3.781715] Internal error: Oops: 37 [#1] ARM [    3.786073] Modules linked in:
>
> [    3.789148] CPU: 0 PID: 1 Comm: swapper Not tainted 4.18.8 #1 [    3.794892] Hardware name: Generic DT based system [    3.799706] PC is at iio_hwmon_probe+0xb4/0x3e4 [    3.804235] LR is at   (null)

The return address is null. This looks like some memory corruption.
Does this kernel boot with the iiomon driver disabled?

Cheers,

Joel

> [    3.807207] pc : [<804eb7a0>]    lr : [<00000000>] psr: a0000013 [    3.813465] sp : 9e477d70  ip : 9e5b4550  fp : 9e477dbc [    3.818681] r10: 00000000  r9 : 00000000  r8 : 80b51d1c [    3.823900] r7 : 9e5b4410  r6 : 9e6f2290  r5 : 00000000  r4 : 9e5b4400 [    3.830418] r3 : 00000000  r2 : fffffdfb  r1 : 00000000  r0 : fffffdfb [    3.836936] Flags: NzCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM Segment none [    3.844068] Control: 00c5387d  Table: 9e764008  DAC: 00000051 [    3.849811] Process swapper (pid: 1, stack limit = 0x2b33fe0f) [    3.855639] Stack: (0x9e477d70 to 0x9e478000) [    3.860004] 7d60:                                     9e5b4400
>
> 9ec1af90 fffffdfb 9e477d88
>
> [    3.868179] 7d80: 8029ea9c 8029ae0c 9e5b4410 7e82968c 9e5b4418
>
> 9e5b4410 00000000 80b51d1c
>
> [    3.876361] 7da0: 00000000 80b51d1c 00000000 00000000 9e477ddc
>
> 9e477dc0 804488f0 804eb6f8
>
> [    3.884541] […….]
>
> 00000000 00000000 00000000
>
> [    4.023518] 7fe0: 00000000 00000000 00000000 00000000 00000013
>
> 00000000 00000000 00000000
>
> [    4.031740] [<804eb7a0>] (iio_hwmon_probe) from [<804488f0>]
>
> (platform_drv_probe+0x58/0xa8)
>
> [    4.040118] [<804488f0>] (platform_drv_probe) from [<80446790>]
>
> (driver_probe_device+0x2f8/0x474)
>
> [    4.048999] [<80446790>] (driver_probe_device) from [<80446a0c>]
>
> (__driver_attach+0x100/0x12c)
>
> [    4.057620] [<80446a0c>] (__driver_attach) from [<804443a4>]
>
> (bus_for_each_dev+0x80/0xc4)
>
> [    4.065802] [<804443a4>] (bus_for_each_dev) from [<80445f14>]
>
> (driver_attach+0x28/0x30)
>
> [    4.073811] [<80445f14>] (driver_attach) from [<8044582c>]
>
> (bus_add_driver+0x154/0x268)
>
> [    4.081832] [<8044582c>] (bus_add_driver) from [<804475f8>]
>
> (driver_register+0x84/0x118)
>
> [    4.089933] [<804475f8>] (driver_register) from [<80448834>]
>
> (__platform_driver_register+0x3c/0x50)
>
> [    4.099003] [<80448834>] (__platform_driver_register) from [<80a26f24>] (iio_hwmon_driver_init+0x20/0x28) [    4.108593] [<80a26f24>] (iio_hwmon_driver_init) from [<80102e20>]
>
> (do_one_initcall+0x4c/0x18c)
>
> [    4.117323] [<80102e20>] (do_one_initcall) from [<80a0116c>]
>
> (kernel_init_freeable+0x1a0/0x270)
>
> [    4.126038] [<80a0116c>] (kernel_init_freeable) from [<806a7e6c>]
>
> (kernel_init+0x18/0x128)
>
> [    4.134315] [<806a7e6c>] (kernel_init) from [<801010e8>]
>
> (ret_from_fork+0x14/0x2c)
>
> [    4.141882] Exception stack(0x9e477fb0 to 0x9e477ff8) [    4.146937] 7fa0:                                     00000000
>
> 00000000 00000000 00000000
>
> [    4.155112] 7fc0: 00000000 00000000 00000000 00000000 00000000
>
> 00000000 00000000 00000000
>
> [    4.163282] 7fe0: 00000000 00000000 00000000 00000000 00000013 00000000 [    4.169903] Code: e0831083 e5860000 e1a01101 e0802001 (e7901001) [    4.176192] ---[ end trace 95853ce787f427d0 ]--- [    4.180830] Kernel panic - not syncing: Fatal exception
>
>
>
> Thanks
>
> Maheswari A