tree 932f2aed75dd3d0c19d57dc55a8143e5858379db
parent b7131ee0bac5e5df73e4098e77bbddb3a31d06ff
author Stefan Haberland <sth@linux.ibm.com> 1605540227 +0100
committer Jens Axboe <axboe@kernel.dk> 1605540482 -0700

s390/dasd: fix null pointer dereference for ERP requests

When requeueing all requests on the device request queue to the blocklayer
we might get to an ERP (error recovery) request that is a copy of an
original CQR.

Those requests do not have blocklayer request information or a pointer to
the dasd_queue set. When trying to access those data it will lead to a
null pointer dereference in dasd_requeue_all_requests().

Fix by checking if the request is an ERP request that can simply be
ignored. The blocklayer request will be requeued by the original CQR that
is on the device queue right behind the ERP request.

Fixes: 9487cfd3430d ("s390/dasd: fix handling of internal requests")
Cc: <stable@vger.kernel.org> #4.16
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>