4.9-stable review patch. If anyone has any objections, please let me know.
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From: Pan Bian bianpan2016@163.com
[ 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 --- drivers/media/i2c/cx25840/cx25840-core.c | 36 ++++++++++++++++++------------- 1 file changed, 21 insertions(+), 15 deletions(-)
--- 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 i2 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 i2 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 i2 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);