[PATCH 6.6 027/105] media: nxp: imx8-isi: m2m: Fix streaming cleanup on release

Greg Kroah-Hartman
2025-10-21T19:53:35Z

From: Guoniu Zhou <guoniu.zhou@nxp.com>

[ Upstream commit 178aa3360220231dd91e7dbc2eb984525886c9c1 ]

If streamon/streamoff calls are imbalanced, such as when exiting an
application with Ctrl+C when streaming, the m2m usage_count will never
reach zero and the ISI channel won't be freed. Besides from that, if the
input line width is more than 2K, it will trigger a WARN_ON():

[ 59.222120] ------------[ cut here ]------------
[ 59.226758] WARNING: drivers/media/platform/nxp/imx8-isi/imx8-isi-hw.c:631 at mxc_isi_channel_chain+0xa4/0x120, CPU#4: v4l2-ctl/654
[ 59.238569] Modules linked in: ap1302
[ 59.242231] CPU: 4 UID: 0 PID: 654 Comm: v4l2-ctl Not tainted 6.16.0-rc4-next-20250704-06511-gff0e002d480a-dirty #258 PREEMPT
[ 59.253597] Hardware name: NXP i.MX95 15X15 board (DT)
[ 59.258720] pstate: 80400009 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[ 59.265669] pc : mxc_isi_channel_chain+0xa4/0x120
[ 59.270358] lr : mxc_isi_channel_chain+0x44/0x120
[ 59.275047] sp : ffff8000848c3b40
[ 59.278348] x29: ffff8000848c3b40 x28: ffff0000859b4c98 x27: ffff800081939f00
[ 59.285472] x26: 000000000000000a x25: ffff0000859b4cb8 x24: 0000000000000001
[ 59.292597] x23: ffff0000816f4760 x22: ffff0000816f4258 x21: ffff000084ceb780
[ 59.299720] x20: ffff000084342ff8 x19: ffff000084340000 x18: 0000000000000000
[ 59.306845] x17: 0000000000000000 x16: 0000000000000000 x15: 0000ffffdb369e1c
[ 59.313969] x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000
[ 59.321093] x11: 0000000000000000 x10: 0000000000000000 x9 : 0000000000000000
[ 59.328217] x8 : ffff8000848c3d48 x7 : ffff800081930b30 x6 : ffff800081930b30
[ 59.335340] x5 : ffff0000859b6000 x4 : ffff80008193ae80 x3 : ffff800081022420
[ 59.342464] x2 : ffff0000852f6900 x1 : 0000000000000001 x0 : ffff000084341000
[ 59.349590] Call trace:
[ 59.352025] mxc_isi_channel_chain+0xa4/0x120 (P)
[ 59.356722] mxc_isi_m2m_streamon+0x160/0x20c
[ 59.361072] v4l_streamon+0x24/0x30
[ 59.364556] __video_do_ioctl+0x40c/0x4a0
[ 59.368560] video_usercopy+0x2bc/0x690
[ 59.372382] video_ioctl2+0x18/0x24
[ 59.375857] v4l2_ioctl+0x40/0x60
[ 59.379168] __arm64_sys_ioctl+0xac/0x104
[ 59.383172] invoke_syscall+0x48/0x104
[ 59.386916] el0_svc_common.constprop.0+0xc0/0xe0
[ 59.391613] do_el0_svc+0x1c/0x28
[ 59.394915] el0_svc+0x34/0xf4
[ 59.397966] el0t_64_sync_handler+0xa0/0xe4
[ 59.402143] el0t_64_sync+0x198/0x19c
[ 59.405801] ---[ end trace 0000000000000000 ]---

Address this issue by moving the streaming preparation and cleanup to
the vb2 .prepare_streaming() and .unprepare_streaming() operations. This
also simplifies the driver by allowing direct usage of the
v4l2_m2m_ioctl_streamon() and v4l2_m2m_ioctl_streamoff() helpers.

Fixes: cf21f328fcaf ("media: nxp: Add i.MX8 ISI driver")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20250821135123.29462-1-laurent.pinchart@ideasonboard.com
Signed-off-by: Guoniu Zhou <guoniu.zhou@nxp.com>
Co-developed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: Guoniu Zhou <guoniu.zhou@nxp.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>
[ Adjust context ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/media/platform/nxp/imx8-isi/imx8-isi-m2m.c | 224 ++++++++-------------
1 file changed, 92 insertions(+), 132 deletions(-)

--- a/drivers/media/platform/nxp/imx8-isi/imx8-isi-m2m.c
+++ b/drivers/media/platform/nxp/imx8-isi/imx8-isi-m2m.c
@@ -43,7 +43,6 @@ struct mxc_isi_m2m_ctx_queue_data {
struct v4l2_pix_format_mplane format;
const struct mxc_isi_format_info *info;
u32 sequence;
- bool streaming;
};

struct mxc_isi_m2m_ctx {
@@ -236,6 +235,65 @@ static void mxc_isi_m2m_vb2_buffer_queue
v4l2_m2m_buf_queue(ctx->fh.m2m_ctx, vbuf);
}

+static int mxc_isi_m2m_vb2_prepare_streaming(struct vb2_queue *q)
+{
+ struct mxc_isi_m2m_ctx *ctx = vb2_get_drv_priv(q);
+ const struct v4l2_pix_format_mplane *out_pix = &ctx->queues.out.format;
+ const struct v4l2_pix_format_mplane *cap_pix = &ctx->queues.cap.format;
+ const struct mxc_isi_format_info *cap_info = ctx->queues.cap.info;
+ const struct mxc_isi_format_info *out_info = ctx->queues.out.info;
+ struct mxc_isi_m2m *m2m = ctx->m2m;
+ int ret;
+
+ guard(mutex)(&m2m->lock);
+
+ if (m2m->usage_count == INT_MAX)
+ return -EOVERFLOW;
+
+ /*
+ * Acquire the pipe and initialize the channel with the first user of
+ * the M2M device.
+ */
+ if (m2m->usage_count == 0) {
+ bool bypass = cap_pix->width == out_pix->width &&
+ cap_pix->height == out_pix->height &&
+ cap_info->encoding == out_info->encoding;
+
+ ret = mxc_isi_channel_acquire(m2m->pipe,
+ &mxc_isi_m2m_frame_write_done,
+ bypass);
+ if (ret)
+ return ret;
+
+ mxc_isi_channel_get(m2m->pipe);
+ }
+
+ m2m->usage_count++;
+
+ /*
+ * Allocate resources for the channel, counting how many users require
+ * buffer chaining.
+ */
+ if (!ctx->chained && out_pix->width > MXC_ISI_MAX_WIDTH_UNCHAINED) {
+ ret = mxc_isi_channel_chain(m2m->pipe);
+ if (ret)
+ goto err_deinit;
+
+ m2m->chained_count++;
+ ctx->chained = true;
+ }
+
+ return 0;
+
+err_deinit:
+ if (--m2m->usage_count == 0) {
+ mxc_isi_channel_put(m2m->pipe);
+ mxc_isi_channel_release(m2m->pipe);
+ }
+
+ return ret;
+}
+
static int mxc_isi_m2m_vb2_start_streaming(struct vb2_queue *q,
unsigned int count)
{
@@ -265,6 +323,35 @@ static void mxc_isi_m2m_vb2_stop_streami
}
}

+static void mxc_isi_m2m_vb2_unprepare_streaming(struct vb2_queue *q)
+{
+ struct mxc_isi_m2m_ctx *ctx = vb2_get_drv_priv(q);
+ struct mxc_isi_m2m *m2m = ctx->m2m;
+
+ guard(mutex)(&m2m->lock);
+
+ /*
+ * If the last context is this one, reset it to make sure the device
+ * will be reconfigured when streaming is restarted.
+ */
+ if (m2m->last_ctx == ctx)
+ m2m->last_ctx = NULL;
+
+ /* Free the channel resources if this is the last chained context. */
+ if (ctx->chained && --m2m->chained_count == 0)
+ mxc_isi_channel_unchain(m2m->pipe);
+ ctx->chained = false;
+
+ /* Turn off the light with the last user. */
+ if (--m2m->usage_count == 0) {
+ mxc_isi_channel_disable(m2m->pipe);
+ mxc_isi_channel_put(m2m->pipe);
+ mxc_isi_channel_release(m2m->pipe);
+ }
+
+ WARN_ON(m2m->usage_count < 0);
+}
+
static const struct vb2_ops mxc_isi_m2m_vb2_qops = {
.queue_setup = mxc_isi_m2m_vb2_queue_setup,
.buf_init = mxc_isi_m2m_vb2_buffer_init,
@@ -272,8 +359,10 @@ static const struct vb2_ops mxc_isi_m2m_
.buf_queue = mxc_isi_m2m_vb2_buffer_queue,
.wait_prepare = vb2_ops_wait_prepare,
.wait_finish = vb2_ops_wait_finish,
+ .prepare_streaming = mxc_isi_m2m_vb2_prepare_streaming,
.start_streaming = mxc_isi_m2m_vb2_start_streaming,
.stop_streaming = mxc_isi_m2m_vb2_stop_streaming,
+ .unprepare_streaming = mxc_isi_m2m_vb2_unprepare_streaming,
};

static int mxc_isi_m2m_queue_init(void *priv, struct vb2_queue *src_vq,
@@ -483,135 +572,6 @@ static int mxc_isi_m2m_s_fmt_vid(struct
return 0;
}

-static int mxc_isi_m2m_streamon(struct file *file, void *fh,
- enum v4l2_buf_type type)
-{
- struct mxc_isi_m2m_ctx *ctx = to_isi_m2m_ctx(fh);
- struct mxc_isi_m2m_ctx_queue_data *q = mxc_isi_m2m_ctx_qdata(ctx, type);
- const struct v4l2_pix_format_mplane *out_pix = &ctx->queues.out.format;
- const struct v4l2_pix_format_mplane *cap_pix = &ctx->queues.cap.format;
- const struct mxc_isi_format_info *cap_info = ctx->queues.cap.info;
- const struct mxc_isi_format_info *out_info = ctx->queues.out.info;
- struct mxc_isi_m2m *m2m = ctx->m2m;
- int ret;
-
- if (q->streaming)
- return 0;
-
- mutex_lock(&m2m->lock);
-
- if (m2m->usage_count == INT_MAX) {
- ret = -EOVERFLOW;
- goto unlock;
- }
-
- /*
- * Acquire the pipe and initialize the channel with the first user of
- * the M2M device.
- */
- if (m2m->usage_count == 0) {
- bool bypass = cap_pix->width == out_pix->width &&
- cap_pix->height == out_pix->height &&
- cap_info->encoding == out_info->encoding;
-
- ret = mxc_isi_channel_acquire(m2m->pipe,
- &mxc_isi_m2m_frame_write_done,
- bypass);
- if (ret)
- goto unlock;
-
- mxc_isi_channel_get(m2m->pipe);
- }
-
- m2m->usage_count++;
-
- /*
- * Allocate resources for the channel, counting how many users require
- * buffer chaining.
- */
- if (!ctx->chained && out_pix->width > MXC_ISI_MAX_WIDTH_UNCHAINED) {
- ret = mxc_isi_channel_chain(m2m->pipe);
- if (ret)
- goto deinit;
-
- m2m->chained_count++;
- ctx->chained = true;
- }
-
- /*
- * Drop the lock to start the stream, as the .device_run() operation
- * needs to acquire it.
- */
- mutex_unlock(&m2m->lock);
- ret = v4l2_m2m_ioctl_streamon(file, fh, type);
- if (ret) {
- /* Reacquire the lock for the cleanup path. */
- mutex_lock(&m2m->lock);
- goto unchain;
- }
-
- q->streaming = true;
-
- return 0;
-
-unchain:
- if (ctx->chained && --m2m->chained_count == 0)
- mxc_isi_channel_unchain(m2m->pipe);
- ctx->chained = false;
-
-deinit:
- if (--m2m->usage_count == 0) {
- mxc_isi_channel_put(m2m->pipe);
- mxc_isi_channel_release(m2m->pipe);
- }
-
-unlock:
- mutex_unlock(&m2m->lock);
- return ret;
-}
-
-static int mxc_isi_m2m_streamoff(struct file *file, void *fh,
- enum v4l2_buf_type type)
-{
- struct mxc_isi_m2m_ctx *ctx = to_isi_m2m_ctx(fh);
- struct mxc_isi_m2m_ctx_queue_data *q = mxc_isi_m2m_ctx_qdata(ctx, type);
- struct mxc_isi_m2m *m2m = ctx->m2m;
-
- v4l2_m2m_ioctl_streamoff(file, fh, type);
-
- if (!q->streaming)
- return 0;
-
- mutex_lock(&m2m->lock);
-
- /*
- * If the last context is this one, reset it to make sure the device
- * will be reconfigured when streaming is restarted.
- */
- if (m2m->last_ctx == ctx)
- m2m->last_ctx = NULL;
-
- /* Free the channel resources if this is the last chained context. */
- if (ctx->chained && --m2m->chained_count == 0)
- mxc_isi_channel_unchain(m2m->pipe);
- ctx->chained = false;
-
- /* Turn off the light with the last user. */
- if (--m2m->usage_count == 0) {
- mxc_isi_channel_disable(m2m->pipe);
- mxc_isi_channel_put(m2m->pipe);
- mxc_isi_channel_release(m2m->pipe);
- }
-
- WARN_ON(m2m->usage_count < 0);
-
- mutex_unlock(&m2m->lock);
-
- q->streaming = false;
-
- return 0;
-}
-
static const struct v4l2_ioctl_ops mxc_isi_m2m_ioctl_ops = {
.vidioc_querycap = mxc_isi_m2m_querycap,

@@ -632,8 +592,8 @@ static const struct v4l2_ioctl_ops mxc_i
.vidioc_prepare_buf = v4l2_m2m_ioctl_prepare_buf,
.vidioc_create_bufs = v4l2_m2m_ioctl_create_bufs,

- .vidioc_streamon = mxc_isi_m2m_streamon,
- .vidioc_streamoff = mxc_isi_m2m_streamoff,
+ .vidioc_streamon = v4l2_m2m_ioctl_streamon,
+ .vidioc_streamoff = v4l2_m2m_ioctl_streamoff,

.vidioc_subscribe_event = v4l2_ctrl_subscribe_event,
.vidioc_unsubscribe_event = v4l2_event_unsubscribe,