[PATCH v4 1/2] media: amphion: drain message work before releasing core state

[Myeonghun Pak <mhun512@gmail.com>]

vpu_core_unregister() frees core->msg_buffer before cancelling the message
workers, although core->msg_fifo still uses the buffer as its backing
storage. A queued worker can read it after it has been freed.

Drain the core and instance message work first, then release core->vpu
and the FIFO buffer. This follows the ordering in vpu_core_suspend().

Fixes: 9f599f351e86 ("media: amphion: add vpu core driver")
Cc: stable@vger.kernel.org
Co-developed-by: Ijae Kim <ae878000@gmail.com>
Signed-off-by: Ijae Kim <ae878000@gmail.com>
Signed-off-by: Myeonghun Pak <mhun512@gmail.com>
---
 drivers/media/platform/amphion/vpu_core.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/drivers/media/platform/amphion/vpu_core.c b/drivers/media/platform/amphion/vpu_core.c
index 85cc4a14f8ed..a0c58ec97a42 100644
--- a/drivers/media/platform/amphion/vpu_core.c
+++ b/drivers/media/platform/amphion/vpu_core.c
@@ -299,22 +299,23 @@ static void vpu_core_put_vpu(struct vpu_core *core)
 	core->vpu->put_vpu(core->vpu);
 }
 
+static void vpu_core_cancel_work(struct vpu_core *core);
+
 static int vpu_core_unregister(struct device *dev, struct vpu_core *core)
 {
 	list_del_init(&core->list);
 
-	vpu_core_put_vpu(core);
-	core->vpu = NULL;
-	kfree(core->msg_buffer);
-	core->msg_buffer = NULL;
-
 	if (core->workqueue) {
-		cancel_work_sync(&core->msg_work);
-		cancel_delayed_work_sync(&core->msg_delayed_work);
+		vpu_core_cancel_work(core);
 		destroy_workqueue(core->workqueue);
 		core->workqueue = NULL;
 	}
 
+	vpu_core_put_vpu(core);
+	core->vpu = NULL;
+	kfree(core->msg_buffer);
+	core->msg_buffer = NULL;
+
 	return 0;
 }
 
-- 
2.53.0