[PATCH v1] ufs: core: Fix error handler host_sem issue

[Peter Wang (王信友)]

On Fri, 2025-10-03 at 09:15 -0700, Bart Van Assche wrote:
> The purpose of hba->host_sem is to serialize power management
> operations, error handling and sysfs callbacks. Hence, I think that
> hba->host_sem should be held around the ufshcd_link_recovery() call
> and hence that the code block that is moved by this patch should not
> be moved.
> 
> Thanks,
> 
> Bart.


Hi Bart,

No, if we take host_sem before checking pm_op_in_progress,
it may cause a deadlock. Consider this case:

ufshcd_wl_suspend
 down(&hba->host_sem);
 __ufshcd_wl_suspend => may trigger ufshcd_err_handler
  ufshcd_execute_start_stop => stuck here waiting for
ufshcd_err_handler to finish

ufshcd_err_handler
 down(&hba->host_sem); => stuck here

Thanks
Peter