matthieu castet a écrit :
Hi,
With my current kernel (2.6.32), if my dvb device is removed while in use, I got [1].
After checking the source code, the problem seems to happen also in master :
If there are users (for example users == -2) :
- dvb_unregister_frontend :
- stop kernel thread with dvb_frontend_stop :
- fepriv->exit = 1;
- thread loop catch stop event and break while loop
- fepriv->thread = NULL; and fepriv->exit = 0;
- dvb_unregister_frontend wait on "fepriv->dvbdev->wait_queue" that fepriv->dvbdev->users==-1.
The user finish :
- dvb_frontend_release - set users to -1
- don't wait wait_queue because fepriv->exit != 1
=> dvb_unregister_frontend never exit the wait queue.
Matthieu
[ 4920.484047] khubd D c2008000 0 198 2 0x00000000
[ 4920.484056] f64c8000 00000046 00000000 c2008000 00000004 c13fa000 c13fa000 f
64c8000
[ 4920.484066] f64c81bc c2008000 00000000 d9d9dce6 00000452 00000001 f64c8000 c
102daad
[ 4920.484075] 00100100 f64c81bc 00000286 f0a7ccc0 f0913404 f0cba404 f644de58 f
092b0a8
[ 4920.484084] Call Trace:
[ 4920.484102] [<c102daad>] ? default_wake_function+0x0/0x8
[ 4920.484147] [<f8cb09e1>] ? dvb_unregister_frontend+0x95/0xcc [dvb_core]
[ 4920.484157] [<c1044412>] ? autoremove_wake_function+0x0/0x2d
[ 4920.484168] [<f8dd1af2>] ? dvb_usb_adapter_frontend_exit+0x12/0x21 [dvb_usb]
[ 4920.484176] [<f8dd12f1>] ? dvb_usb_exit+0x26/0x88 [dvb_usb]
[ 4920.484184] [<f8dd138d>] ? dvb_usb_device_exit+0x3a/0x4a [dvb_usb]
[ 4920.484217] [<f7fe1b08>] ? usb_unbind_interface+0x3f/0xb4 [usbcore]
[ 4920.484227] [<c11a4178>] ? __device_release_driver+0x74/0xb7
[ 4920.484233] [<c11a4247>] ? device_release_driver+0x15/0x1e
[ 4920.484243] [<c11a3a33>] ? bus_remove_device+0x6e/0x87
[ 4920.484249] [<c11a26d6>] ? device_del+0xfa/0x152
[ 4920.484264] [<f7fdf609>] ? usb_disable_device+0x59/0xb9 [usbcore]
[ 4920.484279] [<f7fdb9ee>] ? usb_disconnect+0x70/0xdc [usbcore]
[ 4920.484294] [<f7fdc728>] ? hub_thread+0x521/0xe1d [usbcore]
[ 4920.484301] [<c1044412>] ? autoremove_wake_function+0x0/0x2d
[ 4920.484316] [<f7fdc207>] ? hub_thread+0x0/0xe1d [usbcore]
[ 4920.484321] [<c10441e0>] ? kthread+0x61/0x66
[ 4920.484327] [<c104417f>] ? kthread+0x0/0x66
[ 4920.484336] [<c1003d47>] ? kernel_thread_helper+0x7/0x10
Here a patch that fix the issue
Signed-off-by: Matthieu CASTET <castet.matthieu@xxxxxxx>
diff --git a/drivers/media/dvb/dvb-core/dvb_frontend.c b/drivers/media/dvb/dvb-core/dvb_frontend.c
index 55ea260..6932def 100644
--- a/drivers/media/dvb/dvb-core/dvb_frontend.c
+++ b/drivers/media/dvb/dvb-core/dvb_frontend.c
@@ -95,6 +95,10 @@ MODULE_PARM_DESC(dvb_mfe_wait_time, "Wait up to <mfe_wait_time> seconds on open(
* FESTATE_LOSTLOCK. When the lock has been lost, and we're searching it again.
*/
+#define DVB_FE_NO_EXIT 0
+#define DVB_FE_NORMAL_EXIT 1
+#define DVB_FE_DEVICE_REMOVED 2
+
static DEFINE_MUTEX(frontend_mutex);
struct dvb_frontend_private {
@@ -497,7 +501,7 @@ static int dvb_frontend_is_exiting(struct dvb_frontend *fe)
{
struct dvb_frontend_private *fepriv = fe->frontend_priv;
- if (fepriv->exit)
+ if (fepriv->exit != DVB_FE_NO_EXIT)
return 1;
if (fepriv->dvbdev->writers == 1)
@@ -559,7 +563,7 @@ restart:
if (kthread_should_stop() || dvb_frontend_is_exiting(fe)) {
/* got signal or quitting */
- fepriv->exit = 1;
+ fepriv->exit = DVB_FE_NORMAL_EXIT;
break;
}
@@ -673,7 +677,10 @@ restart:
}
fepriv->thread = NULL;
- fepriv->exit = 0;
+ if (kthread_should_stop())
+ fepriv->exit = DVB_FE_DEVICE_REMOVED;
+ else
+ fepriv->exit = DVB_FE_NO_EXIT;
mb();
dvb_frontend_wakeup(fe);
@@ -686,7 +693,7 @@ static void dvb_frontend_stop(struct dvb_frontend *fe)
dprintk ("%s\n", __func__);
- fepriv->exit = 1;
+ fepriv->exit = DVB_FE_NORMAL_EXIT;
mb();
if (!fepriv->thread)
@@ -755,7 +762,7 @@ static int dvb_frontend_start(struct dvb_frontend *fe)
dprintk ("%s\n", __func__);
if (fepriv->thread) {
- if (!fepriv->exit)
+ if (fepriv->exit == DVB_FE_NO_EXIT)
return 0;
else
dvb_frontend_stop (fe);
@@ -767,7 +774,7 @@ static int dvb_frontend_start(struct dvb_frontend *fe)
return -EINTR;
fepriv->state = FESTATE_IDLE;
- fepriv->exit = 0;
+ fepriv->exit = DVB_FE_NO_EXIT;
fepriv->thread = NULL;
mb();
@@ -1490,7 +1497,7 @@ static int dvb_frontend_ioctl(struct inode *inode, struct file *file,
dprintk("%s (%d)\n", __func__, _IOC_NR(cmd));
- if (fepriv->exit)
+ if (fepriv->exit != DVB_FE_NO_EXIT)
return -ENODEV;
if ((file->f_flags & O_ACCMODE) == O_RDONLY &&
@@ -1916,6 +1923,8 @@ static int dvb_frontend_open(struct inode *inode, struct file *file)
int ret;
dprintk ("%s\n", __func__);
+ if (fepriv->exit == DVB_FE_DEVICE_REMOVED)
+ return -ENODEV;
if (adapter->mfe_shared) {
mutex_lock (&adapter->mfe_lock);
@@ -2008,7 +2017,7 @@ static int dvb_frontend_release(struct inode *inode, struct file *file)
ret = dvb_generic_release (inode, file);
if (dvbdev->users == -1) {
- if (fepriv->exit == 1) {
+ if (fepriv->exit != DVB_FE_NO_EXIT) {
fops_put(file->f_op);
file->f_op = NULL;
wake_up(&dvbdev->wait_queue);
