This is a note to let you know that I've just added the patch titled [media] cx25840: fix unchecked return values to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: cx25840-fix-unchecked-return-values.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From foo@baz Tue Apr 10 10:31:53 CEST 2018 From: Pan Bian <bianpan2016@xxxxxxx> Date: Sun, 23 Apr 2017 10:06:36 -0300 Subject: [media] cx25840: fix unchecked return values From: Pan Bian <bianpan2016@xxxxxxx> [ 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@xxxxxxx> Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx> Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- 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); @@ -631,11 +633,13 @@ 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. @@ -746,11 +750,13 @@ 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); Patches currently in stable-queue which might be from bianpan2016@xxxxxxx are queue-4.4/cx25840-fix-unchecked-return-values.patch queue-4.4/usb-dwc3-keystone-check-return-value.patch queue-4.4/rtc-snvs-fix-an-incorrect-check-of-return-value.patch