[PATCH 0/6] media: vb2: Return queued buffers from start_streaming() on error

[PATCH 0/6] media: vb2: Return queued buffers from start_streaming() on error

[Valery Borovsky]

The vb2 framework hands buffer ownership to the driver via buf_queue()
before calling start_streaming().  If start_streaming() returns an
error without first returning those buffers via vb2_buffer_done(),
vb2_start_streaming() fires WARN_ON(owned_by_drv_count != 0) and the
queued buffers leak.

This was previously fixed for uvcvideo in commit 4cf3b6fd54eb ("media:
uvcvideo: Return queued buffers on start_streaming() failure").  The
same pattern exists in six sibling drivers that still return an errno
early (USB disconnect, signal-interrupted mutex, or media-graph /
format lookup failure) without draining their internal queued-buffer
list.  Each patch reuses or extends the helper / cleanup label that
the driver's other error paths already use.

  airspy.c          - moves mutex_lock above the !s->udev check and
                      jumps to the existing err_clear_bit label, which
                      already drains s->queued_bufs.
  msi2500.c         - rebuilds start_streaming into a goto chain that
                      drains the queue on every failure (including
                      previously-masked set_usb_adc / ctrl_msg paths);
                      parameterizes msi2500_cleanup_queued_bufs() with
                      vb2_buffer_state so the start_streaming path
                      passes _QUEUED.  Rolls back isoc_init via
                      msi2500_isoc_cleanup() on ctrl_msg failure.
  pwc-if.c          - calls pwc_cleanup_queued_bufs(.., _QUEUED) before
                      each early return; state matches the existing
                      pwc_isoc_init() error-path in the same function.
  rtl2832_sdr.c     - calls rtl2832_sdr_cleanup_queued_bufs() before
                      each early return and at the err label.  Adds an
                      explicit success return so the cleanup at err no
                      longer runs on the success path.  Parameterizes
                      the helper with vb2_buffer_state.
  dcmipp-bytecap.c  - replaces the bare -EINVAL return for failed
                      subdev lookup with a goto err_buffer_done.
  sun4i_dma.c       - replaces the bare -EINVAL return for failed
                      csi-format lookup with a goto err_clear_dma_queue.

These sites were located by a Coccinelle pattern that matches
`return -ERRNO` inside a start_streaming(struct vb2_queue *, unsigned
int) callback without a preceding vb2_buffer_done() on the same path.

Build-tested with drivers/media/ allmodconfig.  Not runtime-tested on
any of the six devices.  Maintainers with hardware are kindly asked to
verify nothing regresses on their device.

Valery Borovsky (6):
  media: airspy: Return queued buffers on start_streaming() failure
  media: msi2500: Return queued buffers on start_streaming() failure
  media: pwc: Return queued buffers on start_streaming() failure
  media: rtl2832_sdr: Return queued buffers on start_streaming() failure
  media: stm32-dcmipp: Return queued buffers on start_streaming()
    failure
  media: sun4i-csi: Return queued buffers on start_streaming() failure

 drivers/media/dvb-frontends/rtl2832_sdr.c     | 19 ++++++++---
 .../st/stm32/stm32-dcmipp/dcmipp-bytecap.c    |  6 ++--
 .../platform/sunxi/sun4i-csi/sun4i_dma.c      |  6 ++--
 drivers/media/usb/airspy/airspy.c             |  8 +++--
 drivers/media/usb/msi2500/msi2500.c           | 32 ++++++++++++++-----
 drivers/media/usb/pwc/pwc-if.c                |  8 +++--
 6 files changed, 57 insertions(+), 22 deletions(-)

-- 
2.51.0

[PATCH 1/6] media: airspy: Return queued buffers on start_streaming() failure

[Valery Borovsky]

The vb2 framework hands buffers to the driver via buf_queue() before
calling start_streaming().  If start_streaming() returns an error
without first returning those buffers via vb2_buffer_done(),
vb2_start_streaming() fires WARN_ON(owned_by_drv_count) and the queued
buffers leak.

airspy_start_streaming() returned -ENODEV early when the USB device had
been disconnected (s->udev == NULL) without returning any buffers that
buf_queue() had already accepted.  Take v4l2_lock first and jump to the
existing err_clear_bit label, which already drains s->queued_bufs via
vb2_buffer_done(..., VB2_BUF_STATE_QUEUED) before unlocking.

This mirrors the uvcvideo fix in commit 4cf3b6fd54eb ("media: uvcvideo:
Return queued buffers on start_streaming() failure").

Fixes: 634fe5033951 ("[media] airspy: AirSpy SDR driver")
Cc: stable@vger.kernel.org
Signed-off-by: Valery Borovsky <vebohr@gmail.com>
---
 drivers/media/usb/airspy/airspy.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/media/usb/airspy/airspy.c b/drivers/media/usb/airspy/airspy.c
index 8f6b721ba107..57edb42463e8 100644
--- a/drivers/media/usb/airspy/airspy.c
+++ b/drivers/media/usb/airspy/airspy.c
@@ -522,11 +522,13 @@ static int airspy_start_streaming(struct vb2_queue *vq, unsigned int count)
 
 	dev_dbg(s->dev, "\n");
 
-	if (!s->udev)
-		return -ENODEV;
-
 	mutex_lock(&s->v4l2_lock);
 
+	if (!s->udev) {
+		ret = -ENODEV;
+		goto err_clear_bit;
+	}
+
 	s->sequence = 0;
 
 	set_bit(POWER_ON, &s->flags);
-- 
2.51.0

[PATCH 2/6] media: msi2500: Return queued buffers on start_streaming() failure

[Valery Borovsky]

The vb2 framework hands buffers to the driver via buf_queue() before
calling start_streaming().  If start_streaming() returns an error
without first returning those buffers via vb2_buffer_done(),
vb2_start_streaming() fires WARN_ON(owned_by_drv_count) and the queued
buffers leak.

msi2500_start_streaming() had five error paths that all hit this trap
and were further tangled by ret-overwriting between calls:

  - -ENODEV when the USB device was already disconnected
  - -ERESTARTSYS when mutex_lock_interruptible() was interrupted
  - msi2500_set_usb_adc() failure: ret was silently overwritten by
    the next call (msi2500_isoc_init), so the error was lost entirely
  - msi2500_isoc_init() failure: cleanup_queued_bufs was called, but
    the function then fell through to msi2500_ctrl_msg() and again
    masked the original error by overwriting ret
  - msi2500_ctrl_msg(CMD_START_STREAMING) failure: no cleanup at all,
    leaving isoc URBs submitted with no way for the driver to consume
    them

Consolidate the error paths into a small goto chain.  Every failure
now stops the function, drains the queued-buffer list, and returns
the real error code.  The ctrl_msg failure path also rolls back the
preceding msi2500_isoc_init() via msi2500_isoc_cleanup() before
unlocking and draining.

The cleanup helper takes a vb2_buffer_state argument so that the
start_streaming error paths can pass VB2_BUF_STATE_QUEUED (as
expected by userspace on start_streaming failure) while stop_streaming
keeps its existing VB2_BUF_STATE_ERROR semantics.

This mirrors the uvcvideo fix in commit 4cf3b6fd54eb ("media: uvcvideo:
Return queued buffers on start_streaming() failure").

Fixes: 977e444f59ad ("[media] Mirics MSi3101 SDR Dongle driver")
Cc: stable@vger.kernel.org
Signed-off-by: Valery Borovsky <vebohr@gmail.com>
---
 drivers/media/usb/msi2500/msi2500.c | 32 +++++++++++++++++++++--------
 1 file changed, 24 insertions(+), 8 deletions(-)

diff --git a/drivers/media/usb/msi2500/msi2500.c b/drivers/media/usb/msi2500/msi2500.c
index 1ff98956b680..0614087c3c3c 100644
--- a/drivers/media/usb/msi2500/msi2500.c
+++ b/drivers/media/usb/msi2500/msi2500.c
@@ -541,7 +541,8 @@ static int msi2500_isoc_init(struct msi2500_dev *dev)
 }
 
 /* Must be called with vb_queue_lock hold */
-static void msi2500_cleanup_queued_bufs(struct msi2500_dev *dev)
+static void msi2500_cleanup_queued_bufs(struct msi2500_dev *dev,
+					enum vb2_buffer_state state)
 {
 	unsigned long flags;
 
@@ -554,7 +555,7 @@ static void msi2500_cleanup_queued_bufs(struct msi2500_dev *dev)
 		buf = list_entry(dev->queued_bufs.next,
 				 struct msi2500_frame_buf, list);
 		list_del(&buf->list);
-		vb2_buffer_done(&buf->vb.vb2_buf, VB2_BUF_STATE_ERROR);
+		vb2_buffer_done(&buf->vb.vb2_buf, state);
 	}
 	spin_unlock_irqrestore(&dev->queued_bufs_lock, flags);
 }
@@ -830,25 +831,40 @@ static int msi2500_start_streaming(struct vb2_queue *vq, unsigned int count)
 
 	dev_dbg(dev->dev, "\n");
 
-	if (!dev->udev)
-		return -ENODEV;
+	if (!dev->udev) {
+		ret = -ENODEV;
+		goto err_cleanup;
+	}
 
-	if (mutex_lock_interruptible(&dev->v4l2_lock))
-		return -ERESTARTSYS;
+	if (mutex_lock_interruptible(&dev->v4l2_lock)) {
+		ret = -ERESTARTSYS;
+		goto err_cleanup;
+	}
 
 	/* wake-up tuner */
 	v4l2_subdev_call(dev->v4l2_subdev, core, s_power, 1);
 
 	ret = msi2500_set_usb_adc(dev);
+	if (ret)
+		goto err_unlock_cleanup;
 
 	ret = msi2500_isoc_init(dev);
 	if (ret)
-		msi2500_cleanup_queued_bufs(dev);
+		goto err_unlock_cleanup;
 
 	ret = msi2500_ctrl_msg(dev, CMD_START_STREAMING, 0);
+	if (ret)
+		goto err_isoc_cleanup;
 
 	mutex_unlock(&dev->v4l2_lock);
+	return 0;
 
+err_isoc_cleanup:
+	msi2500_isoc_cleanup(dev);
+err_unlock_cleanup:
+	mutex_unlock(&dev->v4l2_lock);
+err_cleanup:
+	msi2500_cleanup_queued_bufs(dev, VB2_BUF_STATE_QUEUED);
 	return ret;
 }
 
@@ -863,7 +879,7 @@ static void msi2500_stop_streaming(struct vb2_queue *vq)
 	if (dev->udev)
 		msi2500_isoc_cleanup(dev);
 
-	msi2500_cleanup_queued_bufs(dev);
+	msi2500_cleanup_queued_bufs(dev, VB2_BUF_STATE_ERROR);
 
 	/* according to tests, at least 700us delay is required  */
 	msleep(20);
-- 
2.51.0

[PATCH 3/6] media: pwc: Return queued buffers on start_streaming() failure

[Valery Borovsky]

The vb2 framework hands buffers to the driver via buf_queue() before
calling start_streaming().  If start_streaming() returns an error
without first returning those buffers via vb2_buffer_done(),
vb2_start_streaming() fires WARN_ON(owned_by_drv_count) and the queued
buffers leak.

pwc's start_streaming() had two early returns that hit this trap:
-ENODEV when the USB device was already disconnected, and -ERESTARTSYS
when mutex_lock_interruptible() was interrupted by a signal.  Call the
existing pwc_cleanup_queued_bufs() helper with VB2_BUF_STATE_QUEUED
before returning (matching the state already used by the
pwc_isoc_init() error path in the same function).

This mirrors the uvcvideo fix in commit 4cf3b6fd54eb ("media: uvcvideo:
Return queued buffers on start_streaming() failure").

Fixes: ceede9fa8939 ("[media] pwc: Fix locking")
Cc: stable@vger.kernel.org
Signed-off-by: Valery Borovsky <vebohr@gmail.com>
---
 drivers/media/usb/pwc/pwc-if.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/media/usb/pwc/pwc-if.c b/drivers/media/usb/pwc/pwc-if.c
index c416e2fc5754..59b99ac8fcb6 100644
--- a/drivers/media/usb/pwc/pwc-if.c
+++ b/drivers/media/usb/pwc/pwc-if.c
@@ -710,11 +710,15 @@ static int start_streaming(struct vb2_queue *vq, unsigned int count)
 	struct pwc_device *pdev = vb2_get_drv_priv(vq);
 	int r;
 
-	if (!pdev->udev)
+	if (!pdev->udev) {
+		pwc_cleanup_queued_bufs(pdev, VB2_BUF_STATE_QUEUED);
 		return -ENODEV;
+	}
 
-	if (mutex_lock_interruptible(&pdev->v4l2_lock))
+	if (mutex_lock_interruptible(&pdev->v4l2_lock)) {
+		pwc_cleanup_queued_bufs(pdev, VB2_BUF_STATE_QUEUED);
 		return -ERESTARTSYS;
+	}
 	/* Turn on camera and set LEDS on */
 	pwc_camera_power(pdev, 1);
 	pwc_set_leds(pdev, leds[0], leds[1]);
-- 
2.51.0

[PATCH 4/6] media: rtl2832_sdr: Return queued buffers on start_streaming() failure

[Valery Borovsky]

The vb2 framework hands buffers to the driver via buf_queue() before
calling start_streaming().  If start_streaming() returns an error
without first returning those buffers via vb2_buffer_done(),
vb2_start_streaming() fires WARN_ON(owned_by_drv_count) and the queued
buffers leak.

rtl2832_sdr_start_streaming() had multiple error paths that hit this
trap: two direct early returns (-ENODEV, -ERESTARTSYS), plus six
`goto err` paths covering subdev s_power, tuner setup, ADC setup,
stream-buffer allocation, urb allocation, and urb submission failures.
None of them returned the queued buffers.

The original function had no distinct success exit and fell straight
through into the err label, which previously only did mutex_unlock and
"return ret".  Adding queued-buffer cleanup at err must therefore be
paired with an explicit success return; otherwise every successful
start would also drain the buffer queue and kill streaming.  Add that
success return, then add rtl2832_sdr_cleanup_queued_bufs() at the err
label and before each early return.

The cleanup helper takes a vb2_buffer_state argument so that the
start_streaming error paths can pass VB2_BUF_STATE_QUEUED (as
expected by userspace on start_streaming failure) while stop_streaming
keeps its existing VB2_BUF_STATE_ERROR semantics.

This mirrors the uvcvideo fix in commit 4cf3b6fd54eb ("media: uvcvideo:
Return queued buffers on start_streaming() failure").

The err label still does not roll back power_ctrl(), frontend_ctrl(),
the POWER_ON flag, or stream/URB allocations that may have happened
before the failing step.  Those are pre-existing leaks of a different
class and are not addressed here.

Fixes: 771138920eaf ("[media] rtl2832_sdr: Realtek RTL2832 SDR driver module")
Cc: stable@vger.kernel.org
Signed-off-by: Valery Borovsky <vebohr@gmail.com>
---
 drivers/media/dvb-frontends/rtl2832_sdr.c | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/drivers/media/dvb-frontends/rtl2832_sdr.c b/drivers/media/dvb-frontends/rtl2832_sdr.c
index 422d1a7b5456..c564485e3bbb 100644
--- a/drivers/media/dvb-frontends/rtl2832_sdr.c
+++ b/drivers/media/dvb-frontends/rtl2832_sdr.c
@@ -399,7 +399,8 @@ static int rtl2832_sdr_alloc_urbs(struct rtl2832_sdr_dev *dev)
 }
 
 /* Must be called with vb_queue_lock hold */
-static void rtl2832_sdr_cleanup_queued_bufs(struct rtl2832_sdr_dev *dev)
+static void rtl2832_sdr_cleanup_queued_bufs(struct rtl2832_sdr_dev *dev,
+					    enum vb2_buffer_state state)
 {
 	struct platform_device *pdev = dev->pdev;
 	unsigned long flags;
@@ -413,7 +414,7 @@ static void rtl2832_sdr_cleanup_queued_bufs(struct rtl2832_sdr_dev *dev)
 		buf = list_entry(dev->queued_bufs.next,
 				struct rtl2832_sdr_frame_buf, list);
 		list_del(&buf->list);
-		vb2_buffer_done(&buf->vb.vb2_buf, VB2_BUF_STATE_ERROR);
+		vb2_buffer_done(&buf->vb.vb2_buf, state);
 	}
 	spin_unlock_irqrestore(&dev->queued_bufs_lock, flags);
 }
@@ -855,11 +856,15 @@ static int rtl2832_sdr_start_streaming(struct vb2_queue *vq, unsigned int count)
 
 	dev_dbg(&pdev->dev, "\n");
 
-	if (!dev->udev)
+	if (!dev->udev) {
+		rtl2832_sdr_cleanup_queued_bufs(dev, VB2_BUF_STATE_QUEUED);
 		return -ENODEV;
+	}
 
-	if (mutex_lock_interruptible(&dev->v4l2_lock))
+	if (mutex_lock_interruptible(&dev->v4l2_lock)) {
+		rtl2832_sdr_cleanup_queued_bufs(dev, VB2_BUF_STATE_QUEUED);
 		return -ERESTARTSYS;
+	}
 
 	if (d->props->power_ctrl)
 		d->props->power_ctrl(d, 1);
@@ -900,7 +905,11 @@ static int rtl2832_sdr_start_streaming(struct vb2_queue *vq, unsigned int count)
 	if (ret)
 		goto err;
 
+	mutex_unlock(&dev->v4l2_lock);
+	return 0;
+
 err:
+	rtl2832_sdr_cleanup_queued_bufs(dev, VB2_BUF_STATE_QUEUED);
 	mutex_unlock(&dev->v4l2_lock);
 
 	return ret;
@@ -920,7 +929,7 @@ static void rtl2832_sdr_stop_streaming(struct vb2_queue *vq)
 	rtl2832_sdr_kill_urbs(dev);
 	rtl2832_sdr_free_urbs(dev);
 	rtl2832_sdr_free_stream_bufs(dev);
-	rtl2832_sdr_cleanup_queued_bufs(dev);
+	rtl2832_sdr_cleanup_queued_bufs(dev, VB2_BUF_STATE_ERROR);
 	rtl2832_sdr_unset_adc(dev);
 
 	/* sleep tuner */
-- 
2.51.0

[PATCH 5/6] media: stm32-dcmipp: Return queued buffers on start_streaming() failure

[Valery Borovsky]

The vb2 framework hands buffers to the driver via buf_queue() before
calling start_streaming().  If start_streaming() returns an error
without first returning those buffers via vb2_buffer_done(),
vb2_start_streaming() fires WARN_ON(owned_by_drv_count) and the queued
buffers leak.

dcmipp_bytecap_start_streaming() returned -EINVAL when the source
subdevice could not be resolved from the media graph, before
pm_runtime_resume_and_get() and media_pipeline_start() had been called.
The remaining error paths already converge on the err_buffer_done
label, which calls dcmipp_bytecap_all_buffers_done(...,
VB2_BUF_STATE_QUEUED).  Jump to that label directly: the intermediate
err_pm_put / err_media_pipeline_stop labels are skipped, which is
correct because nothing they would undo has happened yet.

This mirrors the uvcvideo fix in commit 4cf3b6fd54eb ("media: uvcvideo:
Return queued buffers on start_streaming() failure").

Fixes: 28e0f3772296 ("media: stm32-dcmipp: STM32 DCMIPP camera interface driver")
Cc: stable@vger.kernel.org
Signed-off-by: Valery Borovsky <vebohr@gmail.com>
---
 .../media/platform/st/stm32/stm32-dcmipp/dcmipp-bytecap.c   | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/media/platform/st/stm32/stm32-dcmipp/dcmipp-bytecap.c b/drivers/media/platform/st/stm32/stm32-dcmipp/dcmipp-bytecap.c
index a42f43d19f9e..f0e809458489 100644
--- a/drivers/media/platform/st/stm32/stm32-dcmipp/dcmipp-bytecap.c
+++ b/drivers/media/platform/st/stm32/stm32-dcmipp/dcmipp-bytecap.c
@@ -401,8 +401,10 @@ static int dcmipp_bytecap_start_streaming(struct vb2_queue *vq,
 	 */
 	if (!vcap->s_subdev) {
 		pad = media_pad_remote_pad_first(&vcap->vdev.entity.pads[0]);
-		if (!pad || !is_media_entity_v4l2_subdev(pad->entity))
-			return -EINVAL;
+		if (!pad || !is_media_entity_v4l2_subdev(pad->entity)) {
+			ret = -EINVAL;
+			goto err_buffer_done;
+		}
 		vcap->s_subdev = media_entity_to_v4l2_subdev(pad->entity);
 		vcap->s_subdev_pad_nb = pad->index;
 	}
-- 
2.51.0

[PATCH 6/6] media: sun4i-csi: Return queued buffers on start_streaming() failure

[Valery Borovsky]

The vb2 framework hands buffers to the driver via buf_queue() before
calling start_streaming().  If start_streaming() returns an error
without first returning those buffers via vb2_buffer_done(),
vb2_start_streaming() fires WARN_ON(owned_by_drv_count) and the queued
buffers leak.

sun4i_csi_start_streaming() returned -EINVAL when no matching CSI
format could be found, before any setup (scratch buffer allocation,
pipeline start) had been performed.  The remaining error paths already
converge on the err_clear_dma_queue label, which calls
return_all_buffers(..., VB2_BUF_STATE_QUEUED) under csi->qlock.  Jump
to that label directly: the intermediate err_disable_device /
err_disable_pipeline / err_free_scratch_buffer labels are skipped,
which is correct because nothing they would undo has happened yet.

This mirrors the uvcvideo fix in commit 4cf3b6fd54eb ("media: uvcvideo:
Return queued buffers on start_streaming() failure").

Fixes: 577bbf23b758 ("media: sunxi: Add A10 CSI driver")
Cc: stable@vger.kernel.org
Signed-off-by: Valery Borovsky <vebohr@gmail.com>
---
 drivers/media/platform/sunxi/sun4i-csi/sun4i_dma.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/media/platform/sunxi/sun4i-csi/sun4i_dma.c b/drivers/media/platform/sunxi/sun4i-csi/sun4i_dma.c
index e911c7f7acc5..4781db21c205 100644
--- a/drivers/media/platform/sunxi/sun4i-csi/sun4i_dma.c
+++ b/drivers/media/platform/sunxi/sun4i-csi/sun4i_dma.c
@@ -234,8 +234,10 @@ static int sun4i_csi_start_streaming(struct vb2_queue *vq, unsigned int count)
 	int ret;
 
 	csi_fmt = sun4i_csi_find_format(&csi->fmt.pixelformat, NULL);
-	if (!csi_fmt)
-		return -EINVAL;
+	if (!csi_fmt) {
+		ret = -EINVAL;
+		goto err_clear_dma_queue;
+	}
 
 	dev_dbg(csi->dev, "Starting capture\n");
 
-- 
2.51.0