[PATCH] remoteproc: imx_rproc: Add mutex protection for workqueue

["Peng Fan (OSS)" <peng.fan@oss.nxp.com>]

From: Peng Fan <peng.fan@nxp.com>

Same as
commit 47e6ab07018e ("remoteproc: imx_dsp_rproc: Add mutex
protection for workqueue") and commit 35bdafda40cc ("remoteproc:
stm32_rproc: Add mutex protection for workqueue"), imx_rproc driver
also has similar issue, although no issue reported until now.

Reuse the commit log from the fix to imx_dsp_rproc:

The workqueue may execute late even after remoteproc is stopped or
stopping, some resources (rpmsg device and endpoint) have been
released in rproc_stop_subdevices(), then rproc_vq_interrupt()
accessing these resources will cause kennel dump.

Call trace:
 virtqueue_add_split
 virtqueue_add_inbuf
 rpmsg_recv_done
 vring_interrupt
 rproc_vq_interrupt
 imx_rproc_vq_work
 process_one_work
 worker_thread
 kthread
 ret_from_fork

Signed-off-by: Peng Fan <peng.fan@nxp.com>
---
 drivers/remoteproc/imx_rproc.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/remoteproc/imx_rproc.c b/drivers/remoteproc/imx_rproc.c
index 74299af1d7f1..f933c8f4fc8b 100644
--- a/drivers/remoteproc/imx_rproc.c
+++ b/drivers/remoteproc/imx_rproc.c
@@ -5,6 +5,7 @@
 
 #include <dt-bindings/firmware/imx/rsrc.h>
 #include <linux/arm-smccc.h>
+#include <linux/cleanup.h>
 #include <linux/clk.h>
 #include <linux/err.h>
 #include <linux/firmware/imx/sci.h>
@@ -785,6 +786,11 @@ static void imx_rproc_vq_work(struct work_struct *work)
 					      rproc_work);
 	struct rproc *rproc = priv->rproc;
 
+	guard(mutex)(&rproc->lock);
+
+	if (rproc->state != RPROC_RUNNING)
+		return;
+
 	idr_for_each(&rproc->notifyids, imx_rproc_notified_idr_cb, rproc);
 }
 
-- 
2.37.1