2017-04-23 13:07:01

by Pan Bian

Subject: [PATCH 1/1] [media] cx25840: fix unchecked return values

From: Pan Bian <[email protected]>

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 <[email protected]>
---
drivers/media/i2c/cx25840/cx25840-core.c | 36 +++++++++++++++++++-------------
1 file changed, 21 insertions(+), 15 deletions(-)

diff --git a/drivers/media/i2c/cx25840/cx25840-core.c b/drivers/media/i2c/cx25840/cx25840-core.c
index b8d3c070..39f51da 100644
--- a/drivers/media/i2c/cx25840/cx25840-core.c
+++ b/drivers/media/i2c/cx25840/cx25840-core.c
@@ -416,11 +416,13 @@ 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);
@@ -630,11 +632,13 @@ 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.
@@ -748,11 +752,13 @@ 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);

--
1.9.1