On Sat, Jan 23, 2021 at 01:13:03PM +0100, Hans de Goede wrote:
We must free/disable all interrupts and cancel all pending works before doing further cleanup.
Before this commit arizona_extcon_remove() was doing several register writes to shut things down before disabling the IRQs and it was cancelling only 1 of the 3 different works used.
Move all the register-writes shutting things down to after the disabling of the IRQs and add the 2 missing cancel_delayed_work_sync() calls.
This fixes various possible races on driver unbind. One of which would always trigger on devices using the mic-clamp feature for jack detection. The ARIZONA_MICD_CLAMP_MODE_MASK update was done before disabling the IRQs, causing:
- arizona_jackdet() to run
- detect a jack being inserted (clamp disabled means jack inserted)
- call arizona_start_mic() which:
3.1 Enables the MICVDD regulator 3.2 takes a pm_runtime_reference
And this was all happening after the ARIZONA_MICD_ENA bit clearing, which would undo 3.1 and 3.2 because the ARIZONA_MICD_CLAMP_MODE_MASK update was being done after the ARIZONA_MICD_ENA bit clearing.
So this means that arizona_extcon_remove() would exit with
- MICVDD enabled and 2. The pm_runtime_reference being unbalanced.
MICVDD still being enabled caused the following oops when the regulator is released by the devm framework:
[ 2850.745757] ------------[ cut here ]------------ [ 2850.745827] WARNING: CPU: 2 PID: 2098 at drivers/regulator/core.c:2123 _regulator_put.part.0+0x19f/0x1b0 [ 2850.745835] Modules linked in: extcon_arizona ... ... [ 2850.746909] Call Trace: [ 2850.746932] regulator_put+0x2d/0x40 [ 2850.746946] release_nodes+0x22a/0x260 [ 2850.746984] __device_release_driver+0x190/0x240 [ 2850.747002] driver_detach+0xd4/0x120 ... [ 2850.747337] ---[ end trace f455dfd7abd9781f ]---
Note this oops is just one of various theoretically possible races caused by the wrong ordering inside arizona_extcon_remove(), this fixes the ordering fixing all possible races, including the reported oops.
Reviewed-by: Andy Shevchenko andy.shevchenko@gmail.com Acked-by: Charles Keepax ckeepax@opensource.cirrus.com Signed-off-by: Hans de Goede hdegoede@redhat.com
Tested-by: Charles Keepax ckeepax@opensource.cirrus.com
Thanks, Charles