On Tue, Mar 17, 2020 at 05:57:05PM +0100, Oliver Graute wrote:

On 16/03/20, Marco Felsch wrote:

quoted

On 20-03-16 18:30, Andy Shevchenko wrote:

quoted

On Mon, Mar 16, 2020 at 03:57:36PM +0100, Oliver Graute wrote:

quoted

On 02/03/20, Oliver Graute wrote:

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Hello,

I have on of these FT6336G Touch Panels here and I try to get it work
with the ft6236 driver. It comes up with model identification "0x11". So
I added that identification to the switch case in
edt_ft5x06_ts_identify(). But it crashes directly after the probe with a
corrupted stack. No clue why. Some ideas?

I still observe sometimes crashes with ft6236G. When it occurs it is
always a stack corruption in the probe function on bootup.

No clue why stack is corrupted sometimes. Is this related to the buggy
revision field?

Some further suggestions for debugging this?

Are you sure you have proper I²C bus settings on electrical level
(pull-up strength, line capacitance, etc.)?

quoted

[    3.806780] edt_ft5x06 1-0038: Model "EP0110M09", Rev. "�", 0x0 sensors
[    3.808468] at24 2-0050: 2-0050 supply vcc not found, using dummy regulator
[    3.814864] DEBUG: edt_ft5x06_ts_probe 1201
[    3.826215] DEBUG: edt_ft5x06_ts_probe 1211
[    3.830512] DEBUG: edt_ft5x06_ts_probe 1214
[    3.834904] input: EP0110M09 as /devices/platform/bus@5a000000/5a820000.i2c/i2c-1/1-0038/input/input0
[    3.844164] at24 2-0050: 4096 byte 24c32 EEPROM, writable, 1 bytes/write
[    3.844264] DEBUG: edt_ft5x06_ts_probe 1222
[    3.850919] i2c i2c-2: LPI2C adapter registered
[    3.855187] edt_ft5x06 1-0038: EDT FT5x06 initialized: IRQ 55, WAKE pin -1, Reset pin -1.

quoted

[    3.867878] Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in: edt_ft5x06_ts_probe+0x5c4/0xb00

Maybe you can look at the assembly to see how compiler puts variables on stack. Also enabling KASAN might help.

This would be the easiest way to debug such failures and since ARMv8
support it you just need to enable it =)

ok, I enabled KASAN and I got the following trace:

Nice. I think it has nothing to do with touch screen.

By the way...

[    0.000000] Linux version 5.6.0-rc1-next-20200214-00057-g9e78f1560095-dirty (alarm@imx8qm) (gcc version 9.2.0 (GCC)) #100 SMP PREEMPT Tue Mar 17 15:54:17 UTC 2020

May you try the latest and greatest release candidate, i.e. v5.6-rc6 w/o any patches applied?
Then, enable only touchscreen and try again.

Otherwise it's probably good to inform ARM + kasan maintainers about the issue.

-- 
With Best Regards,
Andy Shevchenko