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From:   Joseph Hwang <josephsih@chromium.org>
To:     linux-bluetooth@vger.kernel.org, marcel@holtmann.org,
        luiz.dentz@gmail.com, pali@kernel.org
Cc:     chromeos-bluetooth-upstreaming@chromium.org, josephsih@google.com,
        Joseph Hwang <josephsih@chromium.org>,
        Alain Michaud <alainm@chromium.org>,
        Yun-Hao Chung <howardchung@chromium.org>,
        Shuo-Peng Liao <deanliao@chromium.org>
Subject: [BlueZ PATCH v1] monitor: fix division by zero about conn->tx_pkt_med
Date:   Wed, 16 Feb 2022 16:15:18 +0800
Message-Id: <20220216081518.2956782-1-josephsih@chromium.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

In a connection without outgoing traffic, conn->tx_num will remain 0.
In this case, conn->tx_pkt_med should be simply 0 without calculating
"conn->tx_bytes / conn->tx_num".

This was likely to happen, for example, when "btmon -w btsnoop.log"
was launched in the middle of a LE mouse connection, and a number of
incoming ACL Data RX were received as the mouse movements.  When
running "btmon -a btsnoop.log", it would encounter this error.

Reviewed-by: Alain Michaud <alainm@chromium.org>
Reviewed-by: Yun-Hao Chung <howardchung@chromium.org>
Reviewed-by: Shuo-Peng Liao <deanliao@chromium.org>
Signed-off-by: Joseph Hwang <josephsih@chromium.org>
---

 monitor/analyze.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/monitor/analyze.c b/monitor/analyze.c
index 0c74e8f2e..ac23e13bb 100644
--- a/monitor/analyze.c
+++ b/monitor/analyze.c
@@ -161,7 +161,8 @@ static void conn_destroy(void *data)
 		break;
 	}
 
-	conn->tx_pkt_med = conn->tx_bytes / conn->tx_num;
+	if (conn->tx_num > 0)
+		conn->tx_pkt_med = conn->tx_bytes / conn->tx_num;
 
 	printf("  Found %s connection with handle %u\n", str, conn->handle);
 	/* TODO: Store address type */
-- 
2.35.1.265.g69c8d7142f-goog