[PATCH] isdn: mISDNinfineon: fix potential NULL pointer dereference

[Kangjie Lu]

In case ioremap fails, the fix returns -ENOMEM to avoid NULL
pointer dereference.

Signed-off-by: Kangjie Lu <k...@umn.edu>
---
 drivers/isdn/hardware/mISDN/mISDNinfineon.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/isdn/hardware/mISDN/mISDNinfineon.c 
b/drivers/isdn/hardware/mISDN/mISDNinfineon.c
index 3e01012be4ab..0fe6ddcb3fdc 100644
--- a/drivers/isdn/hardware/mISDN/mISDNinfineon.c
+++ b/drivers/isdn/hardware/mISDN/mISDNinfineon.c
@@ -712,8 +712,11 @@ setup_io(struct inf_hw *hw)
                                (ulong)hw->addr.start, (ulong)hw->addr.size);
                        return err;
                }
-               if (hw->ci->addr_mode == AM_MEMIO)
+               if (hw->ci->addr_mode == AM_MEMIO) {
                        hw->addr.p = ioremap(hw->addr.start, hw->addr.size);
+                       if (unlikely(!hw->addr.p))
+                               return -ENOMEM;
+               }
                hw->addr.mode = hw->ci->addr_mode;
                if (debug & DEBUG_HW)
                        pr_notice("%s: IO addr %lx (%lu bytes) mode%d\n",
-- 
2.17.1