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authorFarhan Ali <alifm@linux.ibm.com>2019-07-11 10:28:54 -0400
committerCornelia Huck <cohuck@redhat.com>2019-07-15 14:17:27 +0200
commitf4c9939433bd396d0b08e803b2b880a9d02682b9 (patch)
tree76617329b6742f9c28042482fe40fb365cdf1197 /drivers/s390/cio
parentvfio-ccw: Set pa_nr to 0 if memory allocation fails for pa_iova_pfn (diff)
downloadlinux-dev-f4c9939433bd396d0b08e803b2b880a9d02682b9.tar.xz
linux-dev-f4c9939433bd396d0b08e803b2b880a9d02682b9.zip
vfio-ccw: Don't call cp_free if we are processing a channel program
There is a small window where it's possible that we could be working on an interrupt (queued in the workqueue) and setting up a channel program (i.e allocating memory, pinning pages, translating address). This can lead to allocating and freeing the channel program at the same time and can cause memory corruption. Let's not call cp_free if we are currently processing a channel program. The only way we know for sure that we don't have a thread setting up a channel program is when the state is set to VFIO_CCW_STATE_CP_PENDING. Fixes: d5afd5d135c8 ("vfio-ccw: add handling for async channel instructions") Signed-off-by: Farhan Ali <alifm@linux.ibm.com> Reviewed-by: Cornelia Huck <cohuck@redhat.com> Message-Id: <62e87bf67b38dc8d5760586e7c96d400db854ebe.1562854091.git.alifm@linux.ibm.com> Reviewed-by: Eric Farman <farman@linux.ibm.com> Signed-off-by: Cornelia Huck <cohuck@redhat.com>
Diffstat (limited to 'drivers/s390/cio')
-rw-r--r--drivers/s390/cio/vfio_ccw_drv.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/s390/cio/vfio_ccw_drv.c b/drivers/s390/cio/vfio_ccw_drv.c
index 2b90a5ecaeb9..9208c0e56c33 100644
--- a/drivers/s390/cio/vfio_ccw_drv.c
+++ b/drivers/s390/cio/vfio_ccw_drv.c
@@ -88,7 +88,7 @@ static void vfio_ccw_sch_io_todo(struct work_struct *work)
(SCSW_ACTL_DEVACT | SCSW_ACTL_SCHACT));
if (scsw_is_solicited(&irb->scsw)) {
cp_update_scsw(&private->cp, &irb->scsw);
- if (is_final)
+ if (is_final && private->state == VFIO_CCW_STATE_CP_PENDING)
cp_free(&private->cp);
}
mutex_lock(&private->io_mutex);