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authorStefan Haberland <sth@linux.ibm.com>2020-12-17 16:59:07 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2020-12-29 13:42:42 +0100
commitf9c862c6cc0b3ce03f65c127764ede50a869bbeb (patch)
tree2afd947689b5ed3c9fe09fd08782657d9bea9546
parent02de496d7aa3b43fa23787aa62ea567db7b974d2 (diff)
s390/dasd: fix list corruption of lcu list
commit 53a7f655834c7c335bf683f248208d4fbe4b47bc upstream. In dasd_alias_disconnect_device_from_lcu the device is removed from any list on the LCU. Afterwards the LCU is removed from the lcu list if it does not contain devices any longer. The lcu->lock protects the lcu from parallel updates. But to cancel all workers and wait for completion the lcu->lock has to be unlocked. If two devices are removed in parallel and both are removed from the LCU the first device that takes the lcu->lock again will delete the LCU because it is already empty but the second device also tries to free the LCU which leads to a list corruption of the lcu list. Fix by removing the device right before the lcu is checked without unlocking the lcu->lock in between. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/s390/block/dasd_alias.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/s390/block/dasd_alias.c b/drivers/s390/block/dasd_alias.c
index d76967ee057f..89b708135000 100644
--- a/drivers/s390/block/dasd_alias.c
+++ b/drivers/s390/block/dasd_alias.c
@@ -258,7 +258,6 @@ void dasd_alias_disconnect_device_from_lcu(struct dasd_device *device)
return;
device->discipline->get_uid(device, &uid);
spin_lock_irqsave(&lcu->lock, flags);
- list_del_init(&device->alias_list);
/* make sure that the workers don't use this device */
if (device == lcu->suc_data.device) {
spin_unlock_irqrestore(&lcu->lock, flags);
@@ -285,6 +284,7 @@ void dasd_alias_disconnect_device_from_lcu(struct dasd_device *device)
spin_lock_irqsave(&aliastree.lock, flags);
spin_lock(&lcu->lock);
+ list_del_init(&device->alias_list);
if (list_empty(&lcu->grouplist) &&
list_empty(&lcu->active_devices) &&
list_empty(&lcu->inactive_devices)) {