diff options
| author | Shuah Khan <shuahkh@osg.samsung.com> | 2016-03-22 01:04:05 -0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-04-20 15:45:20 +0900 |
| commit | 3778578c59a727273ea14c9f01b8b123589f7329 (patch) | |
| tree | 52426bba88470ea0c07c1f47358afca216b810a1 | |
| parent | 378219c76f7d9fe4cded8382b955cb8e82963705 (diff) | |
| download | lwn-3778578c59a727273ea14c9f01b8b123589f7329.tar.gz lwn-3778578c59a727273ea14c9f01b8b123589f7329.zip | |
au0828: fix au0828_v4l2_close() dev_state race condition
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@osg.samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/media/usb/au0828/au0828-video.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/media/usb/au0828/au0828-video.c b/drivers/media/usb/au0828/au0828-video.c index a13625722848..5c91e0d4125e 100644 --- a/drivers/media/usb/au0828/au0828-video.c +++ b/drivers/media/usb/au0828/au0828-video.c @@ -1063,7 +1063,7 @@ 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) { |