linux-kernel - [PATCH] rpmsg: glink: Fix channel memory leak

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Date:   Thu, 19 Sep 2019 11:05:40 +0100
From:   Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
To:     ohad@...ery.com, bjorn.andersson@...aro.org
Cc:     linux-arm-msm@...r.kernel.org, linux-remoteproc@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
Subject: [PATCH] rpmsg: glink: Fix channel memory leak

If we stop and start the dsp while channel is open then there is a leak
in the driver as the refcount is not accounted for the open.

This patch checks if the channel is open while running cleanup code
and does an extra kref_put to account for open which would ensure
that channel does not leak.

Originally detected by kmemleak:
  backtrace:
    [<ffffff80088b74d8>] kmemleak_alloc+0x50/0x84
    [<ffffff80081ddbc8>] kmem_cache_alloc_trace+0xd4/0x178
    [<ffffff80086b8bd0>] qcom_glink_alloc_channel+0x34/0x148
    [<ffffff80086b8038>] qcom_glink_work+0x3b0/0x664
    [<ffffff80080c3da8>] process_one_work+0x160/0x2f8
    [<ffffff80080c4198>] worker_thread+0x1e8/0x2d4
    [<ffffff80080c8b24>] kthread+0x128/0x138
    [<ffffff80080845b4>] ret_from_fork+0x10/0x18
    [<ffffffffffffffff>] 0xffffffffffffffff
unreferenced object 0xffffffc02cf5ed80 (size 128):

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
---
 drivers/rpmsg/qcom_glink_native.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/rpmsg/qcom_glink_native.c b/drivers/rpmsg/qcom_glink_native.c
index dc7d3d098fd3..38a10dcc2029 100644
--- a/drivers/rpmsg/qcom_glink_native.c
+++ b/drivers/rpmsg/qcom_glink_native.c
@@ -1660,8 +1660,13 @@ void qcom_glink_native_remove(struct qcom_glink *glink)
 
 	spin_lock_irqsave(&glink->idr_lock, flags);
 	/* Release any defunct local channels, waiting for close-ack */
-	idr_for_each_entry(&glink->lcids, channel, cid)
+	idr_for_each_entry(&glink->lcids, channel, cid) {
+		if (channel->rcid)
+			kref_put(&channel->refcount,
+				 qcom_glink_channel_release);
+
 		kref_put(&channel->refcount, qcom_glink_channel_release);
+	}
 
 	/* Release any defunct local channels, waiting for close-req */
 	idr_for_each_entry(&glink->rcids, channel, cid)
-- 
2.21.0