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    SubjectRe: [PATCH] bttv: fix mutex use before init
    Date
    On Wednesday 15 December 2010, Mauro Carvalho Chehab wrote:
    > Em 15-12-2010 16:44, Chris Clayton escreveu:
    > > On Tuesday 14 December 2010, Brandon Philips wrote:
    > >> On 17:13 Sun 12 Dec 2010, Torsten Kaiser wrote:
    > >>> * change &fh->cap.vb_lock in bttv_open() AND radio_open() to
    > >>> &btv->init.cap.vb_lock
    > >>> * add a mutex_init(&btv->init.cap.vb_lock) to the setup of init in
    > >>> bttv_probe()
    > >>
    > >> That seems like a reasonable suggestion. An openSUSE user submitted this
    > >> bug to our tracker too. Here is the patch I am having him test.
    > >>
    > >> Would you mind testing it?
    > >>
    > >> From 456dc0ce36db523c4c0c8a269f4eec43a72de1dc Mon Sep 17 00:00:00 2001
    > >> From: Brandon Philips <bphilips@suse.de>
    > >> Date: Mon, 13 Dec 2010 16:21:55 -0800
    > >> Subject: [PATCH] bttv: fix locking for btv->init
    > >>
    > >> Fix locking for the btv->init by using btv->init.cap.vb_lock and in the
    > >> process fix uninitialized deref introduced in c37db91fd0d.
    > >>
    > >> Signed-off-by: Brandon Philips <bphilips@suse.de>
    >
    > Hi Brandon & all,
    >
    > While your patch fixes the issue, it has some other troubles, like to the
    > presence of lock code at free_btres_lock(). It is possible to fix, but the
    > better is to just use the core-assisted locking schema. This way, V4L2 core
    > will serialize access to all ioctl's/open/close/mmap/read/poll operations,
    > avoiding to have two processes accessing the hardware at the same time.
    > Also, as there's just one lock, instead of 3, there's no risk of dead
    > locks.
    >
    > The net result is a cleaner code, with just one lock.
    >
    > I tested the patch here with an bttv-based STB board (card=3, tuner=6), and
    > it worked fine for me. Could you please test if this fixes the issue?
    >
    > PS.: The patch is based against the bkl_removal patches, at my linux-next
    > tree:
    >
    > http://git.kernel.org/?p=linux/kernel/git/mchehab/linux-next.git;a=commit;h
    >=673eb9ff33e26ee6f4278cdab06749aef1bbef5b
    >
    > (I just created the bkl_removal branch, so, it may take some time for you
    > to see at the kernel.org mirrors, but it is basically changeset 673eb9ff.
    > You may also just apply it on the top of the master branch of my linux-next
    > tree).
    >
    > ---
    >
    > [media] bttv: Fix locking issues due to BKL removal code
    >
    > The BKL removal patch added a condition where the code would try to use a
    > non-initialized lock. While a patch just addressing the issue is possible,
    > there are some other troubles, like to the presence of lock code at
    > free_btres_lock(), called on some places with the lock already taken. It is
    > possible to fix, but the better is to just use the core-assisted locking
    > schema.
    >
    > This way, V4L2 core will serialize access to all
    > ioctl's/open/close/mmap/read/poll operations, avoiding to have two
    > processes accessing the hardware at the same time. Also, as there's just
    > one lock, instead of 3, there's no risk of dead locks.
    >
    > Tested with bttv STB, Gateway P/N 6000699 (card 3, tuner 6).
    >
    > Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
    >
    > diff --git a/drivers/media/video/bt8xx/bttv-driver.c
    > b/drivers/media/video/bt8xx/bttv-driver.c index a529619..25e1ca0 100644
    > --- a/drivers/media/video/bt8xx/bttv-driver.c
    > +++ b/drivers/media/video/bt8xx/bttv-driver.c
    > @@ -854,7 +854,6 @@ int check_alloc_btres_lock(struct bttv *btv, struct
    > bttv_fh *fh, int bit) xbits |= RESOURCE_VIDEO_READ | RESOURCE_VIDEO_STREAM;
    >
    > /* is it free? */
    > - mutex_lock(&btv->lock);
    > if (btv->resources & xbits) {
    > /* no, someone else uses it */
    > goto fail;
    > @@ -884,11 +883,9 @@ int check_alloc_btres_lock(struct bttv *btv, struct
    > bttv_fh *fh, int bit) /* it's free, grab it */
    > fh->resources |= bit;
    > btv->resources |= bit;
    > - mutex_unlock(&btv->lock);
    > return 1;
    >
    > fail:
    > - mutex_unlock(&btv->lock);
    > return 0;
    > }
    >
    > @@ -940,7 +937,6 @@ void free_btres_lock(struct bttv *btv, struct bttv_fh
    > *fh, int bits) /* trying to free ressources not allocated by us ... */
    > printk("bttv: BUG! (btres)\n");
    > }
    > - mutex_lock(&btv->lock);
    > fh->resources &= ~bits;
    > btv->resources &= ~bits;
    >
    > @@ -951,8 +947,6 @@ void free_btres_lock(struct bttv *btv, struct bttv_fh
    > *fh, int bits)
    >
    > if (0 == (bits & VBI_RESOURCES))
    > disclaim_vbi_lines(btv);
    > -
    > - mutex_unlock(&btv->lock);
    > }
    >
    > /* -----------------------------------------------------------------------
    > */ @@ -1713,28 +1707,20 @@ static int bttv_prepare_buffer(struct
    > videobuf_queue *q,struct bttv *btv,
    >
    > /* Make sure tvnorm and vbi_end remain consistent
    > until we're done. */
    > - mutex_lock(&btv->lock);
    >
    > norm = btv->tvnorm;
    >
    > /* In this mode capturing always starts at defrect.top
    > (default VDELAY), ignoring cropping parameters. */
    > if (btv->vbi_end > bttv_tvnorms[norm].cropcap.defrect.top) {
    > - mutex_unlock(&btv->lock);
    > return -EINVAL;
    > }
    >
    > - mutex_unlock(&btv->lock);
    > -
    > c.rect = bttv_tvnorms[norm].cropcap.defrect;
    > } else {
    > - mutex_lock(&btv->lock);
    > -
    > norm = btv->tvnorm;
    > c = btv->crop[!!fh->do_crop];
    >
    > - mutex_unlock(&btv->lock);
    > -
    > if (width < c.min_scaled_width ||
    > width > c.max_scaled_width ||
    > height < c.min_scaled_height)
    > @@ -1858,7 +1844,6 @@ static int bttv_s_std(struct file *file, void *priv,
    > v4l2_std_id *id) unsigned int i;
    > int err;
    >
    > - mutex_lock(&btv->lock);
    > err = v4l2_prio_check(&btv->prio, fh->prio);
    > if (err)
    > goto err;
    > @@ -1874,7 +1859,6 @@ static int bttv_s_std(struct file *file, void *priv,
    > v4l2_std_id *id) set_tvnorm(btv, i);
    >
    > err:
    > - mutex_unlock(&btv->lock);
    >
    > return err;
    > }
    > @@ -1898,7 +1882,6 @@ static int bttv_enum_input(struct file *file, void
    > *priv, struct bttv *btv = fh->btv;
    > int rc = 0;
    >
    > - mutex_lock(&btv->lock);
    > if (i->index >= bttv_tvcards[btv->c.type].video_inputs) {
    > rc = -EINVAL;
    > goto err;
    > @@ -1928,7 +1911,6 @@ static int bttv_enum_input(struct file *file, void
    > *priv, i->std = BTTV_NORMS;
    >
    > err:
    > - mutex_unlock(&btv->lock);
    >
    > return rc;
    > }
    > @@ -1938,9 +1920,7 @@ static int bttv_g_input(struct file *file, void
    > *priv, unsigned int *i) struct bttv_fh *fh = priv;
    > struct bttv *btv = fh->btv;
    >
    > - mutex_lock(&btv->lock);
    > *i = btv->input;
    > - mutex_unlock(&btv->lock);
    >
    > return 0;
    > }
    > @@ -1952,7 +1932,6 @@ static int bttv_s_input(struct file *file, void
    > *priv, unsigned int i)
    >
    > int err;
    >
    > - mutex_lock(&btv->lock);
    > err = v4l2_prio_check(&btv->prio, fh->prio);
    > if (unlikely(err))
    > goto err;
    > @@ -1965,7 +1944,6 @@ static int bttv_s_input(struct file *file, void
    > *priv, unsigned int i) set_input(btv, i, btv->tvnorm);
    >
    > err:
    > - mutex_unlock(&btv->lock);
    > return 0;
    > }
    >
    > @@ -1979,7 +1957,6 @@ static int bttv_s_tuner(struct file *file, void
    > *priv, if (unlikely(0 != t->index))
    > return -EINVAL;
    >
    > - mutex_lock(&btv->lock);
    > if (unlikely(btv->tuner_type == TUNER_ABSENT)) {
    > err = -EINVAL;
    > goto err;
    > @@ -1995,7 +1972,6 @@ static int bttv_s_tuner(struct file *file, void
    > *priv, btv->audio_mode_gpio(btv, t, 1);
    >
    > err:
    > - mutex_unlock(&btv->lock);
    >
    > return 0;
    > }
    > @@ -2006,10 +1982,8 @@ static int bttv_g_frequency(struct file *file, void
    > *priv, struct bttv_fh *fh = priv;
    > struct bttv *btv = fh->btv;
    >
    > - mutex_lock(&btv->lock);
    > f->type = btv->radio_user ? V4L2_TUNER_RADIO : V4L2_TUNER_ANALOG_TV;
    > f->frequency = btv->freq;
    > - mutex_unlock(&btv->lock);
    >
    > return 0;
    > }
    > @@ -2024,7 +1998,6 @@ static int bttv_s_frequency(struct file *file, void
    > *priv, if (unlikely(f->tuner != 0))
    > return -EINVAL;
    >
    > - mutex_lock(&btv->lock);
    > err = v4l2_prio_check(&btv->prio, fh->prio);
    > if (unlikely(err))
    > goto err;
    > @@ -2039,7 +2012,6 @@ static int bttv_s_frequency(struct file *file, void
    > *priv, if (btv->has_matchbox && btv->radio_user)
    > tea5757_set_freq(btv, btv->freq);
    > err:
    > - mutex_unlock(&btv->lock);
    >
    > return 0;
    > }
    > @@ -2172,7 +2144,6 @@ limit_scaled_size_lock (struct bttv_fh *
    > fh,
    >
    > /* Make sure tvnorm, vbi_end and the current cropping parameters
    > remain consistent until we're done. */
    > - mutex_lock(&btv->lock);
    >
    > b = &bttv_tvnorms[btv->tvnorm].cropcap.bounds;
    >
    > @@ -2250,7 +2221,6 @@ limit_scaled_size_lock (struct bttv_fh *
    > fh, rc = 0; /* success */
    >
    > fail:
    > - mutex_unlock(&btv->lock);
    >
    > return rc;
    > }
    > @@ -2282,9 +2252,7 @@ verify_window_lock (struct bttv_fh *
    > fh, if (V4L2_FIELD_ANY == field) {
    > __s32 height2;
    >
    > - mutex_lock(&fh->btv->lock);
    > height2 = fh->btv->crop[!!fh->do_crop].rect.height >> 1;
    > - mutex_unlock(&fh->btv->lock);
    > field = (win->w.height > height2)
    > ? V4L2_FIELD_INTERLACED
    >
    > : V4L2_FIELD_TOP;
    >
    > @@ -2360,7 +2328,6 @@ static int setup_window_lock(struct bttv_fh *fh,
    > struct bttv *btv, }
    > }
    >
    > - mutex_lock(&fh->cap.vb_lock);
    > /* clip against screen */
    > if (NULL != btv->fbuf.base)
    > n = btcx_screen_clips(btv->fbuf.fmt.width, btv->fbuf.fmt.height,
    > @@ -2412,7 +2379,6 @@ static int setup_window_lock(struct bttv_fh *fh,
    > struct bttv *btv, bttv_overlay_risc(btv, &fh->ov, fh->ovfmt, new);
    > retval = bttv_switch_overlay(btv,fh,new);
    > }
    > - mutex_unlock(&fh->cap.vb_lock);
    > return retval;
    > }
    >
    > @@ -2526,9 +2492,7 @@ static int bttv_try_fmt_vid_cap(struct file *file,
    > void *priv, if (V4L2_FIELD_ANY == field) {
    > __s32 height2;
    >
    > - mutex_lock(&btv->lock);
    > height2 = btv->crop[!!fh->do_crop].rect.height >> 1;
    > - mutex_unlock(&btv->lock);
    > field = (f->fmt.pix.height > height2)
    > ? V4L2_FIELD_INTERLACED
    >
    > : V4L2_FIELD_BOTTOM;
    >
    > @@ -2614,7 +2578,6 @@ static int bttv_s_fmt_vid_cap(struct file *file, void
    > *priv, fmt = format_by_fourcc(f->fmt.pix.pixelformat);
    >
    > /* update our state informations */
    > - mutex_lock(&fh->cap.vb_lock);
    > fh->fmt = fmt;
    > fh->cap.field = f->fmt.pix.field;
    > fh->cap.last = V4L2_FIELD_NONE;
    > @@ -2623,7 +2586,6 @@ static int bttv_s_fmt_vid_cap(struct file *file, void
    > *priv, btv->init.fmt = fmt;
    > btv->init.width = f->fmt.pix.width;
    > btv->init.height = f->fmt.pix.height;
    > - mutex_unlock(&fh->cap.vb_lock);
    >
    > return 0;
    > }
    > @@ -2649,11 +2611,9 @@ static int vidiocgmbuf(struct file *file, void
    > *priv, struct video_mbuf *mbuf) unsigned int i;
    > struct bttv_fh *fh = priv;
    >
    > - mutex_lock(&fh->cap.vb_lock);
    > retval = __videobuf_mmap_setup(&fh->cap, gbuffers, gbufsize,
    > V4L2_MEMORY_MMAP);
    > if (retval < 0) {
    > - mutex_unlock(&fh->cap.vb_lock);
    > return retval;
    > }
    >
    > @@ -2665,7 +2625,6 @@ static int vidiocgmbuf(struct file *file, void *priv,
    > struct video_mbuf *mbuf) for (i = 0; i < gbuffers; i++)
    > mbuf->offsets[i] = i * gbufsize;
    >
    > - mutex_unlock(&fh->cap.vb_lock);
    > return 0;
    > }
    > #endif
    > @@ -2775,10 +2734,8 @@ static int bttv_overlay(struct file *file, void *f,
    > unsigned int on) int retval = 0;
    >
    > if (on) {
    > - mutex_lock(&fh->cap.vb_lock);
    > /* verify args */
    > if (unlikely(!btv->fbuf.base)) {
    > - mutex_unlock(&fh->cap.vb_lock);
    > return -EINVAL;
    > }
    > if (unlikely(!fh->ov.setup_ok)) {
    > @@ -2787,13 +2744,11 @@ static int bttv_overlay(struct file *file, void *f,
    > unsigned int on) }
    > if (retval)
    > return retval;
    > - mutex_unlock(&fh->cap.vb_lock);
    > }
    >
    > if (!check_alloc_btres_lock(btv, fh, RESOURCE_OVERLAY))
    > return -EBUSY;
    >
    > - mutex_lock(&fh->cap.vb_lock);
    > if (on) {
    > fh->ov.tvnorm = btv->tvnorm;
    > new = videobuf_sg_alloc(sizeof(*new));
    > @@ -2805,7 +2760,6 @@ static int bttv_overlay(struct file *file, void *f,
    > unsigned int on)
    >
    > /* switch over */
    > retval = bttv_switch_overlay(btv, fh, new);
    > - mutex_unlock(&fh->cap.vb_lock);
    > return retval;
    > }
    >
    > @@ -2844,7 +2798,6 @@ static int bttv_s_fbuf(struct file *file, void *f,
    > }
    >
    > /* ok, accept it */
    > - mutex_lock(&fh->cap.vb_lock);
    > btv->fbuf.base = fb->base;
    > btv->fbuf.fmt.width = fb->fmt.width;
    > btv->fbuf.fmt.height = fb->fmt.height;
    > @@ -2876,7 +2829,6 @@ static int bttv_s_fbuf(struct file *file, void *f,
    > retval = bttv_switch_overlay(btv, fh, new);
    > }
    > }
    > - mutex_unlock(&fh->cap.vb_lock);
    > return retval;
    > }
    >
    > @@ -2955,7 +2907,6 @@ static int bttv_queryctrl(struct file *file, void
    > *priv, c->id >= V4L2_CID_PRIVATE_LASTP1))
    > return -EINVAL;
    >
    > - mutex_lock(&btv->lock);
    > if (!btv->volume_gpio && (c->id == V4L2_CID_AUDIO_VOLUME))
    > *c = no_ctl;
    > else {
    > @@ -2963,7 +2914,6 @@ static int bttv_queryctrl(struct file *file, void
    > *priv,
    >
    > *c = (NULL != ctrl) ? *ctrl : no_ctl;
    > }
    > - mutex_unlock(&btv->lock);
    >
    > return 0;
    > }
    > @@ -2974,10 +2924,8 @@ static int bttv_g_parm(struct file *file, void *f,
    > struct bttv_fh *fh = f;
    > struct bttv *btv = fh->btv;
    >
    > - mutex_lock(&btv->lock);
    > v4l2_video_std_frame_period(bttv_tvnorms[btv->tvnorm].v4l2_id,
    > &parm->parm.capture.timeperframe);
    > - mutex_unlock(&btv->lock);
    >
    > return 0;
    > }
    > @@ -2993,7 +2941,6 @@ static int bttv_g_tuner(struct file *file, void
    > *priv, if (0 != t->index)
    > return -EINVAL;
    >
    > - mutex_lock(&btv->lock);
    > t->rxsubchans = V4L2_TUNER_SUB_MONO;
    > bttv_call_all(btv, tuner, g_tuner, t);
    > strcpy(t->name, "Television");
    > @@ -3005,7 +2952,6 @@ static int bttv_g_tuner(struct file *file, void
    > *priv, if (btv->audio_mode_gpio)
    > btv->audio_mode_gpio(btv, t, 0);
    >
    > - mutex_unlock(&btv->lock);
    > return 0;
    > }
    >
    > @@ -3014,9 +2960,7 @@ static int bttv_g_priority(struct file *file, void
    > *f, enum v4l2_priority *p) struct bttv_fh *fh = f;
    > struct bttv *btv = fh->btv;
    >
    > - mutex_lock(&btv->lock);
    > *p = v4l2_prio_max(&btv->prio);
    > - mutex_unlock(&btv->lock);
    >
    > return 0;
    > }
    > @@ -3028,9 +2972,7 @@ static int bttv_s_priority(struct file *file, void
    > *f, struct bttv *btv = fh->btv;
    > int rc;
    >
    > - mutex_lock(&btv->lock);
    > rc = v4l2_prio_change(&btv->prio, &fh->prio, prio);
    > - mutex_unlock(&btv->lock);
    >
    > return rc;
    > }
    > @@ -3045,9 +2987,7 @@ static int bttv_cropcap(struct file *file, void
    > *priv, cap->type != V4L2_BUF_TYPE_VIDEO_OVERLAY)
    > return -EINVAL;
    >
    > - mutex_lock(&btv->lock);
    > *cap = bttv_tvnorms[btv->tvnorm].cropcap;
    > - mutex_unlock(&btv->lock);
    >
    > return 0;
    > }
    > @@ -3065,9 +3005,7 @@ static int bttv_g_crop(struct file *file, void *f,
    > struct v4l2_crop *crop) inconsistent with fh->width or fh->height and apps
    > do not expect a change here. */
    >
    > - mutex_lock(&btv->lock);
    > crop->c = btv->crop[!!fh->do_crop].rect;
    > - mutex_unlock(&btv->lock);
    >
    > return 0;
    > }
    > @@ -3091,17 +3029,14 @@ static int bttv_s_crop(struct file *file, void *f,
    > struct v4l2_crop *crop) /* Make sure tvnorm, vbi_end and the current
    > cropping
    > parameters remain consistent until we're done. Note
    > read() may change vbi_end in check_alloc_btres_lock(). */
    > - mutex_lock(&btv->lock);
    > retval = v4l2_prio_check(&btv->prio, fh->prio);
    > if (0 != retval) {
    > - mutex_unlock(&btv->lock);
    > return retval;
    > }
    >
    > retval = -EBUSY;
    >
    > if (locked_btres(fh->btv, VIDEO_RESOURCES)) {
    > - mutex_unlock(&btv->lock);
    > return retval;
    > }
    >
    > @@ -3113,7 +3048,6 @@ static int bttv_s_crop(struct file *file, void *f,
    > struct v4l2_crop *crop)
    >
    > b_top = max(b->top, btv->vbi_end);
    > if (b_top + 32 >= b_bottom) {
    > - mutex_unlock(&btv->lock);
    > return retval;
    > }
    >
    > @@ -3136,12 +3070,8 @@ static int bttv_s_crop(struct file *file, void *f,
    > struct v4l2_crop *crop)
    >
    > btv->crop[1] = c;
    >
    > - mutex_unlock(&btv->lock);
    > -
    > fh->do_crop = 1;
    >
    > - mutex_lock(&fh->cap.vb_lock);
    > -
    > if (fh->width < c.min_scaled_width) {
    > fh->width = c.min_scaled_width;
    > btv->init.width = c.min_scaled_width;
    > @@ -3158,8 +3088,6 @@ static int bttv_s_crop(struct file *file, void *f,
    > struct v4l2_crop *crop) btv->init.height = c.max_scaled_height;
    > }
    >
    > - mutex_unlock(&fh->cap.vb_lock);
    > -
    > return 0;
    > }
    >
    > @@ -3227,7 +3155,6 @@ static unsigned int bttv_poll(struct file *file,
    > poll_table *wait) return videobuf_poll_stream(file, &fh->vbi, wait);
    > }
    >
    > - mutex_lock(&fh->cap.vb_lock);
    > if (check_btres(fh,RESOURCE_VIDEO_STREAM)) {
    > /* streaming capture */
    > if (list_empty(&fh->cap.stream))
    > @@ -3262,7 +3189,6 @@ static unsigned int bttv_poll(struct file *file,
    > poll_table *wait) else
    > rc = 0;
    > err:
    > - mutex_unlock(&fh->cap.vb_lock);
    > return rc;
    > }
    >
    > @@ -3302,14 +3228,11 @@ static int bttv_open(struct file *file)
    > * Let's first copy btv->init at fh, holding cap.vb_lock, and then work
    > * with the rest of init, holding btv->lock.
    > */
    > - mutex_lock(&fh->cap.vb_lock);
    > *fh = btv->init;
    > - mutex_unlock(&fh->cap.vb_lock);
    >
    > fh->type = type;
    > fh->ov.setup_ok = 0;
    >
    > - mutex_lock(&btv->lock);
    > v4l2_prio_open(&btv->prio, &fh->prio);
    >
    > videobuf_queue_sg_init(&fh->cap, &bttv_video_qops,
    > @@ -3317,13 +3240,13 @@ static int bttv_open(struct file *file)
    > V4L2_BUF_TYPE_VIDEO_CAPTURE,
    > V4L2_FIELD_INTERLACED,
    > sizeof(struct bttv_buffer),
    > - fh, NULL);
    > + fh, &btv->lock);
    > videobuf_queue_sg_init(&fh->vbi, &bttv_vbi_qops,
    > &btv->c.pci->dev, &btv->s_lock,
    > V4L2_BUF_TYPE_VBI_CAPTURE,
    > V4L2_FIELD_SEQ_TB,
    > sizeof(struct bttv_buffer),
    > - fh, NULL);
    > + fh, &btv->lock);
    > set_tvnorm(btv,btv->tvnorm);
    > set_input(btv, btv->input, btv->tvnorm);
    >
    > @@ -3346,7 +3269,6 @@ static int bttv_open(struct file *file)
    > bttv_vbi_fmt_reset(&fh->vbi_fmt, btv->tvnorm);
    >
    > bttv_field_count(btv);
    > - mutex_unlock(&btv->lock);
    > return 0;
    > }
    >
    > @@ -3355,7 +3277,6 @@ static int bttv_release(struct file *file)
    > struct bttv_fh *fh = file->private_data;
    > struct bttv *btv = fh->btv;
    >
    > - mutex_lock(&btv->lock);
    > /* turn off overlay */
    > if (check_btres(fh, RESOURCE_OVERLAY))
    > bttv_switch_overlay(btv,fh,NULL);
    > @@ -3385,10 +3306,8 @@ static int bttv_release(struct file *file)
    > * videobuf uses cap.vb_lock - we should avoid holding btv->lock,
    > * otherwise we may have dead lock conditions
    > */
    > - mutex_unlock(&btv->lock);
    > videobuf_mmap_free(&fh->cap);
    > videobuf_mmap_free(&fh->vbi);
    > - mutex_lock(&btv->lock);
    > v4l2_prio_close(&btv->prio, fh->prio);
    > file->private_data = NULL;
    > kfree(fh);
    > @@ -3398,7 +3317,6 @@ static int bttv_release(struct file *file)
    >
    > if (!btv->users)
    > audio_mute(btv, 1);
    > - mutex_unlock(&btv->lock);
    >
    > return 0;
    > }
    > @@ -3502,11 +3420,8 @@ static int radio_open(struct file *file)
    > if (unlikely(!fh))
    > return -ENOMEM;
    > file->private_data = fh;
    > - mutex_lock(&fh->cap.vb_lock);
    > *fh = btv->init;
    > - mutex_unlock(&fh->cap.vb_lock);
    >
    > - mutex_lock(&btv->lock);
    > v4l2_prio_open(&btv->prio, &fh->prio);
    >
    > btv->radio_user++;
    > @@ -3514,7 +3429,6 @@ static int radio_open(struct file *file)
    > bttv_call_all(btv, tuner, s_radio);
    > audio_input(btv,TVAUDIO_INPUT_RADIO);
    >
    > - mutex_unlock(&btv->lock);
    > return 0;
    > }
    >
    > @@ -3524,7 +3438,6 @@ static int radio_release(struct file *file)
    > struct bttv *btv = fh->btv;
    > struct rds_command cmd;
    >
    > - mutex_lock(&btv->lock);
    > v4l2_prio_close(&btv->prio, fh->prio);
    > file->private_data = NULL;
    > kfree(fh);
    > @@ -3532,7 +3445,6 @@ static int radio_release(struct file *file)
    > btv->radio_user--;
    >
    > bttv_call_all(btv, core, ioctl, RDS_CMD_CLOSE, &cmd);
    > - mutex_unlock(&btv->lock);
    >
    > return 0;
    > }
    > @@ -3561,7 +3473,6 @@ static int radio_g_tuner(struct file *file, void
    > *priv, struct v4l2_tuner *t) return -EINVAL;
    > if (0 != t->index)
    > return -EINVAL;
    > - mutex_lock(&btv->lock);
    > strcpy(t->name, "Radio");
    > t->type = V4L2_TUNER_RADIO;
    >
    > @@ -3570,8 +3481,6 @@ static int radio_g_tuner(struct file *file, void
    > *priv, struct v4l2_tuner *t) if (btv->audio_mode_gpio)
    > btv->audio_mode_gpio(btv, t, 0);
    >
    > - mutex_unlock(&btv->lock);
    > -
    > return 0;
    > }
    >
    > @@ -3692,7 +3601,7 @@ static const struct v4l2_file_operations radio_fops =
    > .open = radio_open,
    > .read = radio_read,
    > .release = radio_release,
    > - .ioctl = video_ioctl2,
    > + .unlocked_ioctl = video_ioctl2,
    > .poll = radio_poll,
    > };

    This patch also prevents the oops and the Pinnacle PCTV Pro card TV is fine.
    Thanks Mauro.

    Tested-by: Chris Clayton <chris2553@googlemail.com>

    --
    The more I see, the more I know. The more I know, the less I understand.
    Changing Man - Paul Weller


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