From ed940cd27416f9887864b95e1f8f8845aa9d6391 Mon Sep 17 00:00:00 2001 From: Shuah Khan Date: Tue, 22 Mar 2016 01:04:05 -0300 Subject: [media] au0828: fix au0828_v4l2_close() dev_state race condition 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] [] ? xc5000_sleep+0x8f/0xd0 [xc5000] [ 260.993095] [] ? fe_standby+0x3c/0x50 [tuner] [ 260.993186] [] au0828_v4l2_close+0x53c/0x620 [au0828] [ 260.993298] [] v4l2_release+0xf0/0x210 [videodev] [ 260.993382] [] __fput+0x1fc/0x6c0 [ 260.993449] [] ____fput+0xe/0x10 [ 260.993519] [] task_work_run+0x133/0x1f0 [ 260.993602] [] exit_to_usermode_loop+0x140/0x170 [ 260.993681] [] syscall_return_slowpath+0x16a/0x1a0 [ 260.993754] [] entry_SYSCALL_64_fastpath+0xa6/0xa8 Cc: stable@vger.kernel.org Signed-off-by: Shuah Khan Signed-off-by: Mauro Carvalho Chehab --- drivers/media/usb/au0828/au0828-video.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/media/usb/au0828') diff --git a/drivers/media/usb/au0828/au0828-video.c b/drivers/media/usb/au0828/au0828-video.c index 13f6dab9ccc2..88dcc6e0e178 100644 --- a/drivers/media/usb/au0828/au0828-video.c +++ b/drivers/media/usb/au0828/au0828-video.c @@ -1075,7 +1075,7 @@ static int au0828_v4l2_close(struct file *filp) del_timer_sync(&dev->vbi_timeout); } - if (dev->dev_state == DEV_DISCONNECTED) + if (dev->dev_state & DEV_DISCONNECTED) goto end; if (dev->users == 1) { -- cgit