[no subject]

Device init call                        Device reset call:
do_scsi_scan_host()                     scsi_evt_thread()
 scsi_scan_host_selected()               scsi_evt_emit() <- add wait_event()
  scsi_scan_channel()
   scsi_probe_and_add_lun()
    scsi_target_add()
     device_add() // add kobj.parent
      kobject_uevent_env()
       kobject_get_path()
        fill_kobj_path()
 //call wake_up() after scsi_scan_host_selected is done
                                        kobject_uevent_env()
                                         kobject_get_path() // get valid kobj.parent
					 ...
                                           fill_kobj_path()

>                                     kobject_get_path() // get valid kobj.parent
>                                      fill_kobj_path()
> 
> After we add wake_up at do_scsi_scan_host() in device init thread, we can
> ensure that device reset thread will get kobject after device init thread
> finishes adding parent.
> 
> Signed-off-by: Alice Chao <alice.chao@xxxxxxxxxxxx>
> 
> ---
> 
> Change since v2
> -Change commit: Describes the preblem first and then the solution.
> -Add commit: Add KASAN error log.

Please keep all change history.

e.g.,

See https://lore.kernel.org/lkml/20220326022728.2969-1-jianjun.wang@xxxxxxxxxxxx/
as an example


Thanks,
Miles

> 
> ---
>  drivers/scsi/scsi_lib.c  | 1 +
>  drivers/scsi/scsi_scan.c | 1 +
>  2 files changed, 2 insertions(+)
> 
> diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
> index 0a70aa763a96..abf9a71ed77c 100644
> --- a/drivers/scsi/scsi_lib.c
> +++ b/drivers/scsi/scsi_lib.c
> @@ -2461,6 +2461,7 @@ static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt)
>  		break;
>  	case SDEV_EVT_POWER_ON_RESET_OCCURRED:
>  		envp[idx++] = "SDEV_UA=POWER_ON_RESET_OCCURRED";
> +		wait_event(sdev->host->host_wait, sdev->sdev_gendev.kobj.parent != NULL);
>  		break;
>  	default:
>  		/* do nothing */
> diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
> index f4e6c68ac99e..431f229ac435 100644
> --- a/drivers/scsi/scsi_scan.c
> +++ b/drivers/scsi/scsi_scan.c
> @@ -1904,6 +1904,7 @@ static void do_scsi_scan_host(struct Scsi_Host *shost)
>  	} else {
>  		scsi_scan_host_selected(shost, SCAN_WILD_CARD, SCAN_WILD_CARD,
>  				SCAN_WILD_CARD, 0);
> +		wake_up(&shost->host_wait);
>  	}
>  }
>  
> -- 
> 2.18.0
> 
>