IB/core: Free umem when mm is already gone

Free umem when task's mm is already destroyed by the time
ib_umem_release gets called.

Found by Dotan Barak at Mellanox.

Signed-off-by: Eli Cohen <eli@mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c
index f32ca5fbb26b..6009234e4f9e 100644
--- a/drivers/infiniband/core/umem.c
+++ b/drivers/infiniband/core/umem.c
@@ -209,8 +209,10 @@ void ib_umem_release(struct ib_umem *umem)
         __ib_umem_release(umem->context->device, umem, 1);
 
         mm = get_task_mm(current);
-        if (!mm)
+        if (!mm) {
+                kfree(umem);
                 return;
+        }
 
         diff = PAGE_ALIGN(umem->length + umem->offset) >> PAGE_SHIFT;