--- /dev/null
+From 50b7f1b7236bab08ebbbecf90521e84b068d7a17 Mon Sep 17 00:00:00 2001
+From: Cornelia Huck <cohuck@redhat.com>
+Date: Mon, 11 Mar 2019 10:59:53 +0100
+Subject: vfio: ccw: only free cp on final interrupt
+
+From: Cornelia Huck <cohuck@redhat.com>
+
+commit 50b7f1b7236bab08ebbbecf90521e84b068d7a17 upstream.
+
+When we get an interrupt for a channel program, it is not
+necessarily the final interrupt; for example, the issuing
+guest may request an intermediate interrupt by specifying
+the program-controlled-interrupt flag on a ccw.
+
+We must not switch the state to idle if the interrupt is not
+yet final; even more importantly, we must not free the translated
+channel program if the interrupt is not yet final, or the host
+can crash during cp rewind.
+
+Fixes: e5f84dbaea59 ("vfio: ccw: return I/O results asynchronously")
+Cc: stable@vger.kernel.org # v4.12+
+Reviewed-by: Eric Farman <farman@linux.ibm.com>
+Signed-off-by: Cornelia Huck <cohuck@redhat.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ drivers/s390/cio/vfio_ccw_drv.c | 8 ++++++--
+ 1 file changed, 6 insertions(+), 2 deletions(-)
+
+--- a/drivers/s390/cio/vfio_ccw_drv.c
++++ b/drivers/s390/cio/vfio_ccw_drv.c
+@@ -70,20 +70,24 @@ static void vfio_ccw_sch_io_todo(struct
+ {
+ struct vfio_ccw_private *private;
+ struct irb *irb;
++ bool is_final;
+
+ private = container_of(work, struct vfio_ccw_private, io_work);
+ irb = &private->irb;
+
++ is_final = !(scsw_actl(&irb->scsw) &
++ (SCSW_ACTL_DEVACT | SCSW_ACTL_SCHACT));
+ if (scsw_is_solicited(&irb->scsw)) {
+ cp_update_scsw(&private->cp, &irb->scsw);
+- cp_free(&private->cp);
++ if (is_final)
++ cp_free(&private->cp);
+ }
+ memcpy(private->io_region.irb_area, irb, sizeof(*irb));
+
+ if (private->io_trigger)
+ eventfd_signal(private->io_trigger, 1);
+
+- if (private->mdev)
++ if (private->mdev && is_final)
+ private->state = VFIO_CCW_STATE_IDLE;
+ }
+