[Edge] How can I safely dispose socket?

cmsong-shina · July 15, 2022, 9:11am

I built a driver using UDP socket.

But when I install that driver, then it freeze whole hub about few days later.

After digging in, I found a reason and problematic codes.

That was memory leak and caused by creating socket.

Here is a simplest code to reproduce.

The result of running driver is, increasing memory usage as shown.

2022-07-15T08:28:39 DEBUG LAN BinarySwitch  DEBUG       Current Memory usage: 352.6KiB
2022-07-15T08:28:40 DEBUG LAN BinarySwitch  dumy name device thread event handled
2022-07-15T08:28:49 DEBUG LAN BinarySwitch  DEBUG       Current Memory usage: 354.6KiB
2022-07-15T08:28:50 DEBUG LAN BinarySwitch  dumy name device thread event handled
2022-07-15T08:28:59 DEBUG LAN BinarySwitch  DEBUG       Current Memory usage: 356.2KiB
2022-07-15T08:29:00 DEBUG LAN BinarySwitch  dumy name device thread event handled
2022-07-15T08:29:09 DEBUG LAN BinarySwitch  DEBUG       Current Memory usage: 357.3KiB
2022-07-15T08:29:10 DEBUG LAN BinarySwitch  dumy name device thread event handled
2022-07-15T08:29:19 DEBUG LAN BinarySwitch  DEBUG       Current Memory usage: 359.0KiB
2022-07-15T08:29:20 DEBUG LAN BinarySwitch  dumy name device thread event handled
2022-07-15T08:29:29 DEBUG LAN BinarySwitch  DEBUG       Current Memory usage: 360.4KiB
2022-07-15T08:29:30 DEBUG LAN BinarySwitch  dumy name device thread event handled
2022-07-15T08:29:39 DEBUG LAN BinarySwitch  DEBUG       Current Memory usage: 361.8KiB
2022-07-15T08:29:40 DEBUG LAN BinarySwitch  dumy name device thread event handled
2022-07-15T08:29:49 DEBUG LAN BinarySwitch  DEBUG       Current Memory usage: 364.1KiB
2022-07-15T08:29:50 DEBUG LAN BinarySwitch  dumy name device thread event handled
2022-07-15T08:29:59 DEBUG LAN BinarySwitch  DEBUG       Current Memory usage: 365.7KiB
2022-07-15T08:30:00 DEBUG LAN BinarySwitch  dumy name device thread event handled
2022-07-15T08:30:10 DEBUG LAN BinarySwitch  DEBUG       Current Memory usage: 367.0KiB
2022-07-15T08:30:10 DEBUG LAN BinarySwitch  dumy name device thread event handled
2022-07-15T08:30:20 DEBUG LAN BinarySwitch  DEBUG       Current Memory usage: 368.1KiB
2022-07-15T08:30:20 DEBUG LAN BinarySwitch  dumy name device thread event handled

And you can comment lines that creating socket,

function lifecycles.init(driver, device)
    device.thread:call_on_schedule(10, function()
        do
            collectgarbage("collect")
            collectgarbage("collect")

            local mem_useage = collectgarbage("count")

            log.debug(string.format("DEBUG\tCurrent Memory usage: %.1fKiB",
                mem_useage))
        end

-       for i = 1, 10 do
-           local sock = assert(socket.udp())
-           sock:setoption("broadcast", true)
-           sock:settimeout(3)
-           sock:close()
-       end
+       -- for i = 1, 10 do
+       --     local sock = assert(socket.udp())
+       --     sock:setoption("broadcast", true)
+       --     sock:settimeout(3)
+       --     sock:close()
+       -- end

    end, "Resync Connectivity")
end

You can see there is no leak.

2022-07-15T08:07:06 DEBUG LAN BinarySwitch  DEBUG   Current Memory usage: 352.1KiB
2022-07-15T08:07:06 DEBUG LAN BinarySwitch  dumy name device thread event handled
2022-07-15T08:07:16 DEBUG LAN BinarySwitch  DEBUG   Current Memory usage: 352.1KiB
2022-07-15T08:07:16 DEBUG LAN BinarySwitch  dumy name device thread event handled
2022-07-15T08:07:26 DEBUG LAN BinarySwitch  DEBUG   Current Memory usage: 352.1KiB
2022-07-15T08:07:26 DEBUG LAN BinarySwitch  dumy name device thread event handled
2022-07-15T08:07:36 DEBUG LAN BinarySwitch  DEBUG   Current Memory usage: 352.1KiB
2022-07-15T08:07:36 DEBUG LAN BinarySwitch  dumy name device thread event handled
2022-07-15T08:07:46 DEBUG LAN BinarySwitch  DEBUG   Current Memory usage: 352.1KiB
2022-07-15T08:07:46 DEBUG LAN BinarySwitch  dumy name device thread event handled
2022-07-15T08:07:56 DEBUG LAN BinarySwitch  DEBUG   Current Memory usage: 352.1KiB
2022-07-15T08:07:56 DEBUG LAN BinarySwitch  dumy name device thread event handled
2022-07-15T08:08:06 DEBUG LAN BinarySwitch  DEBUG   Current Memory usage: 352.1KiB
2022-07-15T08:08:06 DEBUG LAN BinarySwitch  dumy name device thread event handled
2022-07-15T08:08:16 DEBUG LAN BinarySwitch  DEBUG   Current Memory usage: 352.1KiB
2022-07-15T08:08:16 DEBUG LAN BinarySwitch  dumy name device thread event handled
2022-07-15T08:08:26 DEBUG LAN BinarySwitch  DEBUG   Current Memory usage: 352.1KiB
2022-07-15T08:08:26 DEBUG LAN BinarySwitch  dumy name device thread event handled
2022-07-15T08:08:36 DEBUG LAN BinarySwitch  DEBUG   Current Memory usage: 352.1KiB
2022-07-15T08:08:36 DEBUG LAN BinarySwitch  dumy name device thread event handled

Is it kind of bug or did I wrong at some points?

Additionally here I append my original code.

local function _scan(opt)
    
    ...
    
    local sock = assert(socket.udp())
    if opt.laddr == "255.255.255.255" then
        sock:setoption("broadcast", true)
    end
    sock:settimeout(opt.timeout)

    local scan_msg = format_scan_message(opt.type, opt.mac)
    log.info(string.format("scanning with message: %s", scan_msg))

    assert(sock:sendto(scan_msg, opt.laddr, PORT), "failed to scan device")

    local msgs = {}

    while true do
        --- There are two possible case, [data, ip, port] or [nil, err, nil]
        local buf, ip, port = sock:receivefrom()
        if buf == nil then
            sock:close()
            return msgs
        end

        msgs[#msgs + 1] = buf

        if opt.find_one then
            sock:close()
            return msgs
        end
    end
end

Thank you in advance for your reply.

nayelyz · July 15, 2022, 7:49pm

Hi, @cmsong-shina!

I’m checking more details about this with the engineering team, once we have more info, we’ll let you know.

TAustin · July 16, 2022, 12:48am

Very interesting!!

cmsong-shina · July 18, 2022, 5:53am

BTW, is there a way restarting driver?

It can be ad-hoc way to keep my hub running.

nayelyz · July 18, 2022, 6:04pm

Following up on this case. @cmsong-shina, could you send me over DM the following info, please?

Hub ID
Account where it’s installed

Also, the team mentioned that a leak in the driver/runtime isn’t enough to cause the system to be unresponsive, so, we need your authorization to check some internal data of the Hub.
To do so, please follow these steps:

Go to the SmartThings Web (my.smartthings.com 1)
Log in to your Samsung Account
Select Menu (⋮) and choose Settings
Toggle on Account Data Access
Select the time period and confirm - In this step, please select “Until turned off”, once the team finishes, we’ll let you know so you can disable it again.

I’ve seen the driver is restarted when the Hub suffered a power outage or when you publish and install a new version.

robert.masen · July 27, 2022, 9:50pm

Thank you for bringing this up, I just wanted to let you know that you have identified a bug that we have a fix for expected in the next release.

BTW, is there a way restarting driver?

There is not at this time a reliable way to restart a single driver on a hub.

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[Edge] How can I safely dispose socket?

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