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: > 1. arizona_jackdet() to run > 2. detect a jack being inserted (clamp disabled means jack inserted) > 3. 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 > 1. 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@xxxxxxxxx> > Acked-by: Charles Keepax <ckeepax@xxxxxxxxxxxxxxxxxxxxx> > Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx> > --- Tested-by: Charles Keepax <ckeepax@xxxxxxxxxxxxxxxxxxxxx> Thanks, Charles
