[POWERPC] mpc5200: Fix null dereference if bestcomm fails to initialize

If the bestcomm initialization fails, calls to the task allocate
function should fail gracefully instead of oopsing with a NULL deref.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/arch/powerpc/sysdev/bestcomm/bestcomm.c b/arch/powerpc/sysdev/bestcomm/bestcomm.c
index f589999361e0..b18cab55a76d 100644
--- a/arch/powerpc/sysdev/bestcomm/bestcomm.c
+++ b/arch/powerpc/sysdev/bestcomm/bestcomm.c
@@ -52,6 +52,10 @@ bcom_task_alloc(int bd_count, int bd_size, int priv_size)
         int i, tasknum = -1;
         struct bcom_task *tsk;
 
+        /* Don't try to do anything if bestcomm init failed */
+        if (!bcom_eng)
+                return NULL;
+
         /* Get and reserve a task num */
         spin_lock(&bcom_eng->lock);