From: Ira Weiny <ira.weiny@intel.com>
Date: Thu, 28 Jul 2016 19:21:12 +0000 (-0400)
Subject: IB/hfi1: Prevent null pointer dereference
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=53445bb32d244b1b32e8d88346a551130fb35544;p=linux-beck.git

IB/hfi1: Prevent null pointer dereference

If a context has not been assigned or assignment failed, pq may be NULL.
Move the unregister within the protection of the null check.

Reviewed-by: Dean Luick <dean.luick@intel.com>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
---

diff --git a/drivers/infiniband/hw/hfi1/user_sdma.c b/drivers/infiniband/hw/hfi1/user_sdma.c
index 586f07807b27..6b8d1e8b6286 100644
--- a/drivers/infiniband/hw/hfi1/user_sdma.c
+++ b/drivers/infiniband/hw/hfi1/user_sdma.c
@@ -472,8 +472,8 @@ int hfi1_user_sdma_free_queues(struct hfi1_filedata *fd)
 	hfi1_cdbg(SDMA, "[%u:%u:%u] Freeing user SDMA queues", uctxt->dd->unit,
 		  uctxt->ctxt, fd->subctxt);
 	pq = fd->pq;
-	hfi1_mmu_rb_unregister(&pq->sdma_rb_root);
 	if (pq) {
+		hfi1_mmu_rb_unregister(&pq->sdma_rb_root);
 		spin_lock_irqsave(&uctxt->sdma_qlock, flags);
 		if (!list_empty(&pq->list))
 			list_del_init(&pq->list);