On 7/23/22 5:12 AM, Bart Van Assche wrote:
On 7/20/22 23:58, peter.wang@xxxxxxxxxxxx wrote:
Both ufshcd_shtdown and ufshcd_wl_shutdown could run concurrently.
And it have race condition when ufshcd_wl_shutdown on-going and
clock/power turn off by ufshcd_shutdown.
The normal case:
ufshcd_wl_shutdown -> ufshcd_shtdown
ufshcd_shtdown should turn off clock/power.
The abnormal case:
ufshcd_shtdown -> ufshcd_wl_shutdown
How can this happen since device_shutdown() iterates over devices in
the opposite order in which these have been created?
Thanks,
Bart.
Hi Bart,
Because kernel_restart is export, and mediatek may call kernel_restart
while shutdown is on going.
EXPORT_SYMBOL_GPL(kernel_restart);
kernel_restart -> kernel_restart_prepare -> device_shutdown
So, there may have two thread execute device_shutdown concurrently.
And the list_lock in device_shutdown function is not protect shutdown
callback function,
caused two callback function(ufshcd_shutdown/ufshcd_wl_shutdown) could
run concurrently.
Here is the error log that two thread in device_shutdown.
[37684.002227] [T1500641] platform +platform:112b0000.ufshci
kpoc_charger: ufshcd-mtk 112b0000.ufshci: [name:core&]shutdown
[37684.002264] [T1600339] scsi +scsi:0:0:0:49488 charger_thread:
ufs_device_wlun 0:0:0:49488: [name:core&]shutdown
Thanks.
BR
Peter
