armmmci rmmod causes hung tasks

[Martin DEVERA]

Hello,

on STM32MP1 with almost vanilla 5.7.7 in single CPU mode. Pair of
modprobe armmmci ; rmmod armmmci

causes rmmod and kworker to hang. I should note that no MMC is detected
on the board (SDIO device on MMC bus is not responding).
On another board (where SDIO is responding) rmmod works.

It seems as another manifestation of https://lkml.org/lkml/2019/8/27/945

Thanks.

INFO: task kworker/0:1:12 blocked for more than 368 seconds.
       Not tainted 5.7.7kdb-00003-g10397828596c-dirty #224
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kworker/0:1     D    0    12      2 0x00000000
Workqueue: events_freezable mmc_rescan
(__schedule) from (schedule+0x5b/0x90)
(schedule) from (schedule_timeout+0x1b/0xa0)
(schedule_timeout) from (__wait_for_common+0x7d/0xdc)
(__wait_for_common) from (mmc_wait_for_req_done+0x1b/0x8c)
(mmc_wait_for_req_done) from (mmc_wait_for_cmd+0x4d/0x68)
(mmc_wait_for_cmd) from (mmc_io_rw_direct_host+0x87/0xc8)
(mmc_io_rw_direct_host) from (sdio_reset+0x3b/0x58)
(sdio_reset) from (mmc_rescan+0x15d/0x1d4)
(mmc_rescan) from (process_one_work+0xdd/0x168)
(process_one_work) from (worker_thread+0x17d/0x1ec)
(worker_thread) from (kthread+0x9b/0xa4)
(kthread) from (ret_from_fork+0x11/0x28)

INFO: task rmmod:308 blocked for more than 368 seconds.
       Not tainted 5.7.7kdb-00003-g10397828596c-dirty #224
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
rmmod           D    0   308    222 0x00000000
(__schedule) from (schedule+0x5b/0x90)
(schedule) from (schedule_timeout+0x1b/0xa0)
(schedule_timeout) from (__wait_for_common+0x7d/0xdc)
(__wait_for_common) from (__flush_work+0xb3/0x110)
(__flush_work) from (__cancel_work_timer+0x97/0xf0)
(__cancel_work_timer) from (mmc_stop_host+0x29/0x88)
(mmc_stop_host) from (mmc_remove_host+0x9/0x22)
(mmc_remove_host) from (mmci_remove+0x19/0x92 [armmmci])
(mmci_remove [armmmci]) from (amba_remove+0x13/0x42)
(amba_remove) from (device_release_driver_internal+0x89/0xe4)
(device_release_driver_internal) from (driver_detach+0x57/0x60)
(driver_detach) from (bus_remove_driver+0x53/0x84)
(bus_remove_driver) from (mmci_driver_exit+0x9/0x11dc [armmmci])
(mmci_driver_exit [armmmci]) from (sys_delete_module+0x115/0x154)
(sys_delete_module) from (ret_fast_syscall+0x1/0x5a)