kernel_optimize_test/drivers/s390
Julian Wiedmann ce28867fd2 s390/qeth: don't clobber buffer on async TX completion
If qeth_qdio_output_handler() detects that a transmit requires async
completion, it replaces the pending buffer's metadata object
(qeth_qdio_out_buffer) so that this queue buffer can be re-used while
the data is pending completion.

Later when the CQ indicates async completion of such a metadata object,
qeth_qdio_cq_handler() tries to free any data associated with this
object (since HW has now completed the transfer). By calling
qeth_clear_output_buffer(), it erronously operates on the queue buffer
that _previously_ belonged to this transfer ... but which has been
potentially re-used several times by now.
This results in double-free's of the buffer's data, and failing
transmits as the buffer descriptor is scrubbed in mid-air.

The correct way of handling this situation is to
1. scrub the queue buffer when it is prepared for re-use, and
2. later obtain the data addresses from the async-completion notifier
   (ie. the AOB), instead of the queue buffer.

All this only affects qeth devices used for af_iucv HiperTransport.

Fixes: 0da9581ddb ("qeth: exploit asynchronous delivery of storage blocks")
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-06-30 21:19:48 +09:00
..
block Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux 2018-06-19 07:44:51 +09:00
char treewide: Use array_size() in vzalloc() 2018-06-12 16:19:22 -07:00
cio Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux 2018-06-19 07:44:51 +09:00
crypto treewide: kzalloc() -> kcalloc() 2018-06-12 16:19:22 -07:00
net s390/qeth: don't clobber buffer on async TX completion 2018-06-30 21:19:48 +09:00
scsi SCSI misc on 20180610 2018-06-10 13:01:12 -07:00
virtio virtio/s390: implement PM operations for virtio_ccw 2018-02-14 14:34:09 +02:00
Makefile kbuild: rename built-in.o to built-in.a 2018-03-26 02:01:19 +09:00