cx25840: fix unchecked return values

[ Upstream commit 35378ce143071c2a6bad4b59a000e9b9f8f6ea67 ]

In functions cx25840_initialize(), cx231xx_initialize(), and
cx23885_initialize(), the return value of create_singlethread_workqueue()
is used without validation. This may result in NULL dereference and cause
kernel crash. This patch fixes it.

Signed-off-by: Pan Bian <bianpan2016@163.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/media/i2c/cx25840/cx25840-core.c b/drivers/media/i2c/cx25840/cx25840-core.c
index 142ae28803bb859d5d375976867f9c2badd5ad9c..d558ed3e59c61b3f4a3fc105d5721a47d1d56ed1 100644 (file)
--- a/drivers/media/i2c/cx25840/cx25840-core.c
+++ b/drivers/media/i2c/cx25840/cx25840-core.c
@@ -420,11 +420,13 @@ static void cx25840_initialize(struct i2c_client *client)
        INIT_WORK(&state->fw_work, cx25840_work_handler);
        init_waitqueue_head(&state->fw_wait);
        q = create_singlethread_workqueue("cx25840_fw");
-       prepare_to_wait(&state->fw_wait, &wait, TASK_UNINTERRUPTIBLE);
-       queue_work(q, &state->fw_work);
-       schedule();
-       finish_wait(&state->fw_wait, &wait);
-       destroy_workqueue(q);
+       if (q) {
+               prepare_to_wait(&state->fw_wait, &wait, TASK_UNINTERRUPTIBLE);
+               queue_work(q, &state->fw_work);
+               schedule();
+               finish_wait(&state->fw_wait, &wait);
+               destroy_workqueue(q);
+       }
 
        /* 6. */
        cx25840_write(client, 0x115, 0x8c);
@@ -634,11 +636,13 @@ static void cx23885_initialize(struct i2c_client *client)
        INIT_WORK(&state->fw_work, cx25840_work_handler);
        init_waitqueue_head(&state->fw_wait);
        q = create_singlethread_workqueue("cx25840_fw");
-       prepare_to_wait(&state->fw_wait, &wait, TASK_UNINTERRUPTIBLE);
-       queue_work(q, &state->fw_work);
-       schedule();
-       finish_wait(&state->fw_wait, &wait);
-       destroy_workqueue(q);
+       if (q) {
+               prepare_to_wait(&state->fw_wait, &wait, TASK_UNINTERRUPTIBLE);
+               queue_work(q, &state->fw_work);
+               schedule();
+               finish_wait(&state->fw_wait, &wait);
+               destroy_workqueue(q);
+       }
 
        /* Call the cx23888 specific std setup func, we no longer rely on
         * the generic cx24840 func.
@@ -752,11 +756,13 @@ static void cx231xx_initialize(struct i2c_client *client)
        INIT_WORK(&state->fw_work, cx25840_work_handler);
        init_waitqueue_head(&state->fw_wait);
        q = create_singlethread_workqueue("cx25840_fw");
-       prepare_to_wait(&state->fw_wait, &wait, TASK_UNINTERRUPTIBLE);
-       queue_work(q, &state->fw_work);
-       schedule();
-       finish_wait(&state->fw_wait, &wait);
-       destroy_workqueue(q);
+       if (q) {
+               prepare_to_wait(&state->fw_wait, &wait, TASK_UNINTERRUPTIBLE);
+               queue_work(q, &state->fw_work);
+               schedule();
+               finish_wait(&state->fw_wait, &wait);
+               destroy_workqueue(q);
+       }
 
        cx25840_std_setup(client);