On Thursday 20 March 2008 19:22:12 Mauro Carvalho Chehab wrote:
8<
Latest git with or without your patch still causes the oops..
The call trace that seems to be causing this oops is
radio
|-> ioctl(
|->videodev.c:__video_do_ioctl
|->v4l1-compat.c:v4l_compat_translate_ioctl
| case VIDIOCGTUNER: /* get tuner information */
| {
| struct video_tuner *tun = arg;
|
| memset(&tun2,0,sizeof(tun2));
|__ err = drv(inode, file, VIDIOC_G_TUNER, &tun2);
|->videodev.c:__video_do_ioctl
| case VIDIOC_G_TUNER:
| {
| struct v4l2_tuner *p=arg;
| __u32 index=p->index;
|
| if (!vfd->vidioc_g_tuner)
| break;
|
| memset(p,0,sizeof(*p));
| p->index=index;
|
| ret=vfd->vidioc_g_tuner(file, fh, p);
|_
|-> bttv_driver.c:radio_g_tuner
| struct bttv_fh *fh = priv;
| struct bttv *btv = fh->btv;
|
| if (UNSET == bttv_tvcards[btv->c.type].tuner)
| return -EINVAL;
| if (0 != t->index)
| return -EINVAL;
| mutex_lock(&btv->lock);
|__
|-> mutex.c:__mutex_lock_common
| struct task_struct *task = current;
| struct mutex_waiter waiter;
| unsigned int old_val;
| unsigned long flags;
|
| spin_lock_mutex(&lock->wait_lock, flags);
|
| debug_mutex_lock_common(lock, &waiter);
| mutex_acquire(&lock->dep_map, subclass, 0, ip);
| debug_mutex_add_waiter(lock, &waiter,
task_thread_info(task));
|
| /* add waiting tasks to the end of the
waitqueue (FIFO): */
| list_add_tail(&waiter.list, &lock->wait_list);
^^^^
This is where it oops because lock->wait_list->next is NULL.
BUT, changing:
memset(&tun2,0,sizeof(tun2));
to
memset(&tun2,-1,sizeof(tun2));
in
v4l1-compat.c:v4l_compat_translate_ioctl
...
case VIDIOCGTUNER:
changes
lock->wait_list->next from being NULL to something else, and the oops move to
the next case statement i.e. VIDIOCGFREQ
--
