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alistair23-linux/drivers/s390
Stefan Haberland a7c256a9fd s390/dasd: fix list corruption of lcu list
commit 53a7f65583 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: 8e09f21574 ("[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>
2020-12-30 11:51:34 +01:00
..
block s390/dasd: fix list corruption of lcu list 2020-12-30 11:51:34 +01:00
char s390 updates for the 5.4 merge window 2019-09-17 14:04:43 -07:00
cio s390/cio: fix use-after-free in ccw_device_destroy_console 2020-12-30 11:51:23 +01:00
crypto s390/pkey: fix paes selftest failure with paes and pkey static build 2020-11-10 12:37:32 +01:00
net s390/qeth: fix tear down of async TX buffers 2020-12-02 08:49:51 +01:00
scsi scsi: zfcp: Fix use-after-free in request timeout handlers 2020-08-26 10:40:52 +02:00
virtio virtio/s390: fix race on airq_areas[] 2019-07-26 13:36:18 +02:00
Makefile s390: remove pointless drivers-y in drivers/s390/Makefile 2019-09-16 13:21:51 +02:00