xconn-leak-detect

X11 connection leak detection tool.

Sometimes we encounter errors like: Maximum number of clients reached.

This is usually due to a connection leak.

To find which process is suspicious, you can use sudo lsof -f -U /tmp/.X11-unix/X0 to list all X11 connections and find out which process has the most connections.

And then you can use this tool to analyze where the leaks happen in your application.

Build

make -j`nproc`

Usage

LD_PRELOAD=./xconn-leak-detect.so your_application

output should look like this:

leaks detected:
    open connections:
        connection: 0x55904e1f9460
        calltrace:
            ./libxconn_leak_detect.so(xcb_connect+0x87) [0x7f8c2ea627d5]
            /lib/x86_64-linux-gnu/libX11.so.6(_XConnectXCB+0x1ba) [0x7f8c2e8bed0a]
            /lib/x86_64-linux-gnu/libX11.so.6(XOpenDisplay+0xd7) [0x7f8c2e8af0c7]
            glxgears(+0x30f2) [0x55901e7c00f2]
            /lib/x86_64-linux-gnu/libc.so.6(+0x27b8a) [0x7f8c2e5dfb8a]
            /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0x85) [0x7f8c2e5dfc45]
            glxgears(+0x3161) [0x55901e7c0161]

TODO:

• count per frame
• add logging
• capture necessary signals
• work with X11 sessions
• call location is not really readable, add calltrace
• optimize memory usage
• hook xcb instead of x11

License

MIT