[PATCH v7 13/19] media: meson: vdec: Fix race conditions in job abort sequence

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

Implement proper cleanup inside vdec_m2m_job_abort to safely stop
the hardware job sequence during a streaming abort or teardown.

Without this, if a job is aborted right after being triggered, the
deferred work item (esparser_queue_work) scheduled by device_run
could continue running concurrently. This leads to unexpected behavior
and potential use-after-free bugs if session structures are cleared.

Fix this by flagging the session to stop via WRITE_ONCE, synchronously
canceling any pending parser work, and safely clearing the active core
session pointer under the core lock protection.

Cc: Nicolas Dufresne <nicolas@ndufresne.ca>
Signed-off-by: Anand Moon <linux.amoon@gmail.com>
---
 drivers/staging/media/meson/vdec/vdec.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/staging/media/meson/vdec/vdec.c b/drivers/staging/media/meson/vdec/vdec.c
index b3e1d99e8889f..ac86a9c4febff 100644
--- a/drivers/staging/media/meson/vdec/vdec.c
+++ b/drivers/staging/media/meson/vdec/vdec.c
@@ -167,6 +167,17 @@ static void vdec_m2m_device_run(void *priv)
 static void vdec_m2m_job_abort(void *priv)
 {
 	struct amvdec_session *sess = priv;
+	struct amvdec_core *core = sess->core;
+
+	WRITE_ONCE(sess->should_stop, 1);
+
+	cancel_work_sync(&sess->esparser_queue_work);
+
+	mutex_lock(&core->lock);
+	if (core->cur_sess == sess)
+		/* Safely clear hardware ownership since we were confirmed as the owner */
+		smp_store_release(&core->cur_sess, NULL);
+	mutex_unlock(&core->lock);
 
 	v4l2_m2m_job_finish(sess->core->m2m_dev, sess->m2m_ctx);
 }
-- 
2.50.1