dasd_alias_add_device() moves devices to the active_devices list in case
of a scheduled LCU update regardless if they have previously been in a
pavgroup or not.
Example: device A and B are in the same pavgroup.
Device A has already been in a pavgroup and the private->pavgroup pointer
is set and points to a valid pavgroup. While going through dasd_add_device
it is moved from the pavgroup to the active_devices list.
In parallel device B might be removed from the same pavgroup in
remove_device_from_lcu() which in turn checks if the group is empty
and deletes it accordingly because device A has already been removed from
there.
When now device A enters remove_device_from_lcu() it is tried to remove it
from the pavgroup again because the pavgroup pointer is still set and again
the empty group will be cleaned up which leads to a list corruption.
Fix by setting private->pavgroup to NULL in dasd_add_device.
If the device has been the last device on the pavgroup an empty pavgroup
remains but this will be cleaned up by the scheduled lcu_update which
iterates over all existing pavgroups.
Fixes: 8e09f21574ea ("[S390] dasd: add hyper PAV support to DASD device driver, part 1")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Stefan Haberland <sth@xxxxxxxxxxxxx>
Reviewed-by: Jan Hoeppner <hoeppner@xxxxxxxxxxxxx>
---
drivers/s390/block/dasd_alias.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/s390/block/dasd_alias.c b/drivers/s390/block/dasd_alias.c
index f841518de6c5..60344e13e87b 100644
--- a/drivers/s390/block/dasd_alias.c
+++ b/drivers/s390/block/dasd_alias.c
@@ -642,6 +642,7 @@ int dasd_alias_add_device(struct dasd_device *device)
}
if (lcu->flags & UPDATE_PENDING) {
list_move(&device->alias_list, &lcu->active_devices);
+ private->pavgroup = NULL;
_schedule_lcu_update(lcu, device);
}
spin_unlock_irqrestore(&lcu->lock, flags);
--
2.17.1
