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authorStefan Haberland <sth@linux.ibm.com>2020-12-17 18:59:06 +0300
committerJens Axboe <axboe@kernel.dk>2020-12-17 23:41:30 +0300
commit0ede91f83aa335da1c3ec68eb0f9e228f269f6d8 (patch)
tree85c23719a9d31d5b34a16cb7c21a3c2b30f622de /drivers/s390
parenta29ea01653493b94ea12bb2b89d1564a265081b6 (diff)
downloadlinux-0ede91f83aa335da1c3ec68eb0f9e228f269f6d8.tar.xz
s390/dasd: fix list corruption of pavgroup group list
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@vger.kernel.org Signed-off-by: Stefan Haberland <sth@linux.ibm.com> Reviewed-by: Jan Hoeppner <hoeppner@linux.ibm.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'drivers/s390')
-rw-r--r--drivers/s390/block/dasd_alias.c1
1 files changed, 1 insertions, 0 deletions
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);