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>
---
drivers/media/usb/au0828/au0828-video.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/media/usb/au0828/au0828-video.c b/drivers/media/usb/au0828/au0828-video.c
index 13f6dab..88dcc6e 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) {
--
2.5.0
--
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