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Commit c3736674 authored by Mike Snitzer's avatar Mike Snitzer
Browse files

dm mpath: fix uninitialized 'pg_init_wait' waitqueue_head NULL pointer 



Initialize all the scsi_dh related 'struct multipath' members regardless
of whether a scsi_dh is in use or not.

The subtle (and fragile) SCSI-assuming legacy code clearly needs further
decoupling from non-SCSI (and/or developer understanding).

Fixes: 8d47e659 ("dm mpath: remove unnecessary NVMe branching in favor of scsi_dh checks")
Reported-by: default avatarBart Van Assche <bart.vanassche@wdc.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent 0c8efd61

drivers/md/dm-mpath.c

+10 −11
Original line number Diff line number Diff line
@@ -223,6 +223,16 @@ static int alloc_multipath_stage2(struct dm_target *ti, struct multipath *m) 


	dm_table_set_type(ti->table, m->queue_mode);



	/*

	 * Init fields that are only used when a scsi_dh is attached

	 * - must do this unconditionally (really doesn't hurt non-SCSI uses)

	 */

	set_bit(MPATHF_QUEUE_IO, &m->flags);

	atomic_set(&m->pg_init_in_progress, 0);

	atomic_set(&m->pg_init_count, 0);

	m->pg_init_delay_msecs = DM_PG_INIT_DELAY_DEFAULT;

	init_waitqueue_head(&m->pg_init_wait);



	return 0;

}
@@ -331,7 +341,6 @@ static void __switch_pg(struct multipath *m, struct priority_group *pg) 
		set_bit(MPATHF_PG_INIT_REQUIRED, &m->flags);

		set_bit(MPATHF_QUEUE_IO, &m->flags);

	} else {

		/* FIXME: not needed if no scsi_dh is attached */

		clear_bit(MPATHF_PG_INIT_REQUIRED, &m->flags);

		clear_bit(MPATHF_QUEUE_IO, &m->flags);

	}
@@ -823,16 +832,6 @@ static int setup_scsi_dh(struct block_device *bdev, struct multipath *m, char ** 
			 */

			kfree(m->hw_handler_name);

			m->hw_handler_name = attached_handler_name;



			/*

			 * Init fields that are only used when a scsi_dh is attached

			 */

			if (!test_and_set_bit(MPATHF_QUEUE_IO, &m->flags)) {

				atomic_set(&m->pg_init_in_progress, 0);

				atomic_set(&m->pg_init_count, 0);

				m->pg_init_delay_msecs = DM_PG_INIT_DELAY_DEFAULT;

				init_waitqueue_head(&m->pg_init_wait);

			}

		}

	}