[PATCH -next] tee: fix possible error pointer ctx dereferencing

[Sumit Garg]

Add check for valid ctx pointer and then only dereference ctx to
configure supp_nowait flag.

Fixes: 42bf4152d8a7 ("tee: add supp_nowait flag in tee_context struct")
Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Signed-off-by: Sumit Garg <sumit.garg@xxxxxxxxxx>
---
 drivers/tee/tee_core.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/tee/tee_core.c b/drivers/tee/tee_core.c
index 25f3b9c..06fbfc0 100644
--- a/drivers/tee/tee_core.c
+++ b/drivers/tee/tee_core.c
@@ -993,7 +993,9 @@ tee_client_open_context(struct tee_context *start,
 	 * tee_client_open_session() if any in kernel client requires
 	 * different behaviour.
 	 */
-	ctx->supp_nowait = true;
+	if (!IS_ERR(ctx))
+		ctx->supp_nowait = true;
+
 	return ctx;
 }
 EXPORT_SYMBOL_GPL(tee_client_open_context);
-- 
2.7.4