The patch below does not apply to the 5.3-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 71cddb7097e2b0feb855d7fd7d59afd12cbee4bb Mon Sep 17 00:00:00 2001
From: Pi-Hsun Shih pihsun@chromium.org Date: Wed, 4 Sep 2019 14:26:13 +0800 Subject: [PATCH] platform/chrome: cros_ec_rpmsg: Fix race with host command when probe failed
Since the rpmsg_endpoint is created before probe is called, it's possible that a host event is received during cros_ec_register, and there would be some pending work in the host_event_work workqueue while cros_ec_register is called.
If cros_ec_register fails, when the leftover work in host_event_work run, the ec_dev from the drvdata of the rpdev could be already set to NULL, causing kernel crash when trying to run cros_ec_get_next_event.
Fix this by creating the rpmsg_endpoint by ourself, and when cros_ec_register fails (or on remove), destroy the endpoint first (to make sure there's no more new calls to cros_ec_rpmsg_callback), and then cancel all works in the host_event_work workqueue.
Cc: stable@vger.kernel.org Fixes: 2de89fd98958 ("platform/chrome: cros_ec: Add EC host command support using rpmsg") Signed-off-by: Pi-Hsun Shih pihsun@chromium.org Signed-off-by: Enric Balletbo i Serra enric.balletbo@collabora.com
diff --git a/drivers/platform/chrome/cros_ec_rpmsg.c b/drivers/platform/chrome/cros_ec_rpmsg.c index 8b6bd775cc9a..0c3738c3244d 100644 --- a/drivers/platform/chrome/cros_ec_rpmsg.c +++ b/drivers/platform/chrome/cros_ec_rpmsg.c @@ -41,6 +41,7 @@ struct cros_ec_rpmsg { struct rpmsg_device *rpdev; struct completion xfer_ack; struct work_struct host_event_work; + struct rpmsg_endpoint *ept; };
/** @@ -72,7 +73,6 @@ static int cros_ec_pkt_xfer_rpmsg(struct cros_ec_device *ec_dev, struct cros_ec_command *ec_msg) { struct cros_ec_rpmsg *ec_rpmsg = ec_dev->priv; - struct rpmsg_device *rpdev = ec_rpmsg->rpdev; struct ec_host_response *response; unsigned long timeout; int len; @@ -85,7 +85,7 @@ static int cros_ec_pkt_xfer_rpmsg(struct cros_ec_device *ec_dev, dev_dbg(ec_dev->dev, "prepared, len=%d\n", len);
reinit_completion(&ec_rpmsg->xfer_ack); - ret = rpmsg_send(rpdev->ept, ec_dev->dout, len); + ret = rpmsg_send(ec_rpmsg->ept, ec_dev->dout, len); if (ret) { dev_err(ec_dev->dev, "rpmsg send failed\n"); return ret; @@ -196,11 +196,24 @@ static int cros_ec_rpmsg_callback(struct rpmsg_device *rpdev, void *data, return 0; }
+static struct rpmsg_endpoint * +cros_ec_rpmsg_create_ept(struct rpmsg_device *rpdev) +{ + struct rpmsg_channel_info chinfo = {}; + + strscpy(chinfo.name, rpdev->id.name, RPMSG_NAME_SIZE); + chinfo.src = rpdev->src; + chinfo.dst = RPMSG_ADDR_ANY; + + return rpmsg_create_ept(rpdev, cros_ec_rpmsg_callback, NULL, chinfo); +} + static int cros_ec_rpmsg_probe(struct rpmsg_device *rpdev) { struct device *dev = &rpdev->dev; struct cros_ec_rpmsg *ec_rpmsg; struct cros_ec_device *ec_dev; + int ret;
ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL); if (!ec_dev) @@ -225,7 +238,18 @@ static int cros_ec_rpmsg_probe(struct rpmsg_device *rpdev) INIT_WORK(&ec_rpmsg->host_event_work, cros_ec_rpmsg_host_event_function);
- return cros_ec_register(ec_dev); + ec_rpmsg->ept = cros_ec_rpmsg_create_ept(rpdev); + if (!ec_rpmsg->ept) + return -ENOMEM; + + ret = cros_ec_register(ec_dev); + if (ret < 0) { + rpmsg_destroy_ept(ec_rpmsg->ept); + cancel_work_sync(&ec_rpmsg->host_event_work); + return ret; + } + + return 0; }
static void cros_ec_rpmsg_remove(struct rpmsg_device *rpdev) @@ -234,7 +258,7 @@ static void cros_ec_rpmsg_remove(struct rpmsg_device *rpdev) struct cros_ec_rpmsg *ec_rpmsg = ec_dev->priv;
cros_ec_unregister(ec_dev); - + rpmsg_destroy_ept(ec_rpmsg->ept); cancel_work_sync(&ec_rpmsg->host_event_work); }
@@ -271,7 +295,6 @@ static struct rpmsg_driver cros_ec_driver_rpmsg = { }, .probe = cros_ec_rpmsg_probe, .remove = cros_ec_rpmsg_remove, - .callback = cros_ec_rpmsg_callback, };
module_rpmsg_driver(cros_ec_driver_rpmsg);