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From:   Bjorn Andersson <quic_bjorande@quicinc.com>
To:     Bjorn Andersson <andersson@kernel.org>,
        Mathieu Poirier <mathieu.poirier@linaro.org>,
        Sarannya S <quic_sarannya@quicinc.com>,
        "Chris Lew" <quic_clew@quicinc.com>
CC:     Deepak Kumar Singh <quic_deesin@quicinc.com>,
        <linux-arm-msm@vger.kernel.org>,
        <linux-remoteproc@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        kernel test robot <lkp@intel.com>,
        "Dan Carpenter" <dan.carpenter@linaro.org>
Subject: [PATCH] rpmsg: glink: Avoid dereferencing NULL channel
Date:   Mon, 17 Jul 2023 09:55:38 -0700
Message-ID: <20230717165538.1542034-1-quic_bjorande@quicinc.com>
MIME-Version: 1.0
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Precedence: bulk

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@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/r/202307160800.sb7gMnL6-lkp@intel.com/
Signed-off-by: Bjorn Andersson <quic_bjorande@quicinc.com>
---
 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