This is a note to let you know that I've just added the patch titled [media] au0828: fix au0828_v4l2_close() dev_state race condition 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: au0828-fix-au0828_v4l2_close-dev_state-race-condition.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 ed940cd27416f9887864b95e1f8f8845aa9d6391 Mon Sep 17 00:00:00 2001 From: Shuah Khan <shuahkh@xxxxxxxxxxxxxxx> Date: Tue, 22 Mar 2016 01:04:05 -0300 Subject: [media] au0828: fix au0828_v4l2_close() dev_state race condition From: Shuah Khan <shuahkh@xxxxxxxxxxxxxxx> commit ed940cd27416f9887864b95e1f8f8845aa9d6391 upstream. au0828_v4l2_close() check for dev_state == DEV_DISCONNECTED will fail to detect the device disconnected state correctly, if au0828_v4l2_open() runs to set the DEV_INITIALIZED bit. A loop test of bind/unbind found this bug by increasing the likelihood of au0828_v4l2_open() occurring while unbind is in progress. When au0828_v4l2_close() fails to detect that the device is in disconnect state, it attempts to power down the device and fails with the following general protection fault: [ 260.992962] Call Trace: [ 260.993008] [<ffffffffa0f80f0f>] ? xc5000_sleep+0x8f/0xd0 [xc5000] [ 260.993095] [<ffffffffa0f6803c>] ? fe_standby+0x3c/0x50 [tuner] [ 260.993186] [<ffffffffa0ef541c>] au0828_v4l2_close+0x53c/0x620 [au0828] [ 260.993298] [<ffffffffa0d08ec0>] v4l2_release+0xf0/0x210 [videodev] [ 260.993382] [<ffffffff81570f9c>] __fput+0x1fc/0x6c0 [ 260.993449] [<ffffffff815714ce>] ____fput+0xe/0x10 [ 260.993519] [<ffffffff8116eb83>] task_work_run+0x133/0x1f0 [ 260.993602] [<ffffffff810035d0>] exit_to_usermode_loop+0x140/0x170 [ 260.993681] [<ffffffff810061ca>] syscall_return_slowpath+0x16a/0x1a0 [ 260.993754] [<ffffffff82835fb3>] entry_SYSCALL_64_fastpath+0xa6/0xa8 Signed-off-by: Shuah Khan <shuahkh@xxxxxxxxxxxxxxx> Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/media/usb/au0828/au0828-video.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/media/usb/au0828/au0828-video.c +++ b/drivers/media/usb/au0828/au0828-video.c @@ -1007,7 +1007,7 @@ static int au0828_v4l2_close(struct file del_timer_sync(&dev->vbi_timeout); } - if (dev->dev_state == DEV_DISCONNECTED) + if (dev->dev_state & DEV_DISCONNECTED) goto end; if (dev->users == 1) { Patches currently in stable-queue which might be from shuahkh@xxxxxxxxxxxxxxx are queue-4.4/au0828-fix-au0828_v4l2_close-dev_state-race-condition.patch queue-4.4/au0828-fix-dev_state-handling.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html