[PATCH] rpmsg: glink: Avoid dereferencing NULL channel

[Bjorn Andersson]

The newly introduced signal command handler checks for non-existing
channel and print an error message, but then continues on to dereference
that same channel.

Instead abort the handler when no channel is found.

Fixes: a2b73aa512a4 ("rpmsg: glink: Add support to handle signals command")
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Closes: https://lore.kernel.org/r/202307160800.sb7gMnL6-lkp@xxxxxxxxx/
Signed-off-by: Bjorn Andersson <quic_bjorande@xxxxxxxxxxx>
---
 drivers/rpmsg/qcom_glink_native.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/rpmsg/qcom_glink_native.c b/drivers/rpmsg/qcom_glink_native.c
index e10c05ed21bb..82d460ff4777 100644
--- a/drivers/rpmsg/qcom_glink_native.c
+++ b/drivers/rpmsg/qcom_glink_native.c
@@ -1070,8 +1070,10 @@ static void qcom_glink_handle_signals(struct qcom_glink *glink,
 	spin_lock_irqsave(&glink->idr_lock, flags);
 	channel = idr_find(&glink->rcids, rcid);
 	spin_unlock_irqrestore(&glink->idr_lock, flags);
-	if (!channel)
+	if (!channel) {
 		dev_err(glink->dev, "signal for non-existing channel\n");
+		return;
+	}
 
 	enable = sigs & NATIVE_DSR_SIG || sigs & NATIVE_CTS_SIG;
 
-- 
2.25.1