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

Shengjiu Wang
2022-09-26T13:53:09Z

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()
access these resources will cause kennel dump.

Call trace:
virtqueue_add_split+0x1ac/0x560
virtqueue_add_inbuf+0x4c/0x60
rpmsg_recv_done+0x15c/0x294
vring_interrupt+0x6c/0xa4
rproc_vq_interrupt+0x30/0x50
imx_dsp_rproc_vq_work+0x24/0x40 [imx_dsp_rproc]
process_one_work+0x1d0/0x354
worker_thread+0x13c/0x470
kthread+0x154/0x160
ret_from_fork+0x10/0x20

Add mutex protection in imx_dsp_rproc_vq_work(), if the state is
not running, then just skip calling rproc_vq_interrupt().

Also the flush workqueue operation can't be added in rproc stop
for same reason.

Fixes: ec0e5549f358 ("remoteproc: imx_dsp_rproc: Add remoteproc driver for DSP on i.MX")
Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
---
drivers/remoteproc/imx_dsp_rproc.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/remoteproc/imx_dsp_rproc.c b/drivers/remoteproc/imx_dsp_rproc.c
index 899aa8dd12f0..95da1cbefacf 100644
--- a/drivers/remoteproc/imx_dsp_rproc.c
+++ b/drivers/remoteproc/imx_dsp_rproc.c
@@ -347,9 +347,6 @@ static int imx_dsp_rproc_stop(struct rproc *rproc)
struct device *dev = rproc->dev.parent;
int ret = 0;

- /* Make sure work is finished */
- flush_work(&priv->rproc_work);
-
if (rproc->state == RPROC_CRASHED) {
priv->flags &= ~REMOTE_IS_READY;
return 0;
@@ -432,9 +429,18 @@ static void imx_dsp_rproc_vq_work(struct work_struct *work)
{
struct imx_dsp_rproc *priv = container_of(work, struct imx_dsp_rproc,
rproc_work);
+ struct rproc *rproc = priv->rproc;
+
+ mutex_lock(&rproc->lock);
+
+ if (rproc->state != RPROC_RUNNING)
+ goto unlock_mutex;

rproc_vq_interrupt(priv->rproc, 0);
rproc_vq_interrupt(priv->rproc, 1);
+
+unlock_mutex:
+ mutex_unlock(&rproc->lock);
}

/**
--
2.34.1