[PATCH v5 4/6] media: meson: vdec: Handle kthread error and free codec private data

[Anand Moon <linux.amoon@gmail.com>]

vdec_start_streaming() launches a recycle thread when required by the
codec. If kthread_run() fails, the previous error path only powered off
the hardware, leaving sess->priv and codec state allocated. This caused
a permanent leak of the codec context and associated DMA buffers.

Fix this by adding an err_cleanup path: if thread creation fails, call
codec_ops->stop() to release the codec context and clear sess->priv,
then power off the hardware. Also reset core->cur_sess and sess->status
to avoid stale references.

This change closes the memory leak on kthread_run() failure and ensures
proper cleanup of codec resources.

Cc: Nicolas Dufresne <nicolas@ndufresne.ca>
Reported-by: Sashiko <sashiko-bot@kernel.org>
Closes: https://lore.kernel.org/all/20260521090944.F35401F00A3D@smtp.kernel.org/
Fixes: 3e7f51bd9607 ("media: meson: add v4l2 m2m video decoder driver")
Signed-off-by: Anand Moon <linux.amoon@gmail.com>
---
v5: The vdec_poweron() function invoked earlier allocates dynamic memory for
the codec context and assigns it to sess->priv. When kthread_run() fails,
this new error path calls vdec_poweroff() which stops the hardware but
doesn't free sess->priv.
---
 drivers/staging/media/meson/vdec/vdec.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/staging/media/meson/vdec/vdec.c b/drivers/staging/media/meson/vdec/vdec.c
index 52ace4de967c..b31bf08af88e 100644
--- a/drivers/staging/media/meson/vdec/vdec.c
+++ b/drivers/staging/media/meson/vdec/vdec.c
@@ -345,13 +345,25 @@ static int vdec_start_streaming(struct vb2_queue *q, unsigned int count)
 
 	sess->sequence_cap = 0;
 	sess->sequence_out = 0;
-	if (vdec_codec_needs_recycle(sess))
+	if (vdec_codec_needs_recycle(sess)) {
 		sess->recycle_thread = kthread_run(vdec_recycle_thread, sess,
 						   "vdec_recycle");
+		if (IS_ERR(sess->recycle_thread)) {
+			ret = PTR_ERR(sess->recycle_thread);
+			sess->recycle_thread = NULL;
+			goto err_cleanup;
+		}
+	}
 
 	schedule_work(&sess->esparser_queue_work);
 	return 0;
 
+err_cleanup:
+	if (codec_ops && codec_ops->stop && sess->priv) {
+		codec_ops->stop(sess);
+		sess->priv = NULL;
+	}
+	vdec_poweroff(sess);
 vififo_free:
 	mutex_lock(&core->lock);
 	core->cur_sess = NULL;
-- 
2.50.1