@@ -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 */
@@ -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);
}
}
Device reset thread uses kobject_uevent_env() to get kobj.parent after scsi_evt_emit(), and it races with device init thread which calls device_add() to create kobj.parent before kobject_uevent_env(). Device reset call trace: fill_kobj_path kobject_get_path kobject_uevent_env scsi_evt_emit <- add wait_event() scsi_evt_thread Device init call trace: fill_kobj_path kobject_get_path kobject_uevent_env device_add <- create kobj.parent scsi_target_add scsi_sysfs_add_sdev scsi_add_lun scsi_probe_and_add_lun These two jobs are scheduled asynchronously, we can't guaranteed that kobj.parent will be created in device init thread before device reset thread calls kobj_get_path(). To resolve the racing issue between device init thread and device reset thread, we use wait_event() in scsi_evt_emit() to wait for device_add() to complete the creation of kobj.parent. Signed-off-by: Alice Chao <alice.chao@mediatek.com> --- drivers/scsi/scsi_lib.c | 1 + drivers/scsi/scsi_scan.c | 1 + 2 files changed, 2 insertions(+)