fifo_test

Demonstrates an issue with SSH logins when running a program that uses 100% of a CPU while being in SCHED_FIFO, and after another program instantiates a Gtk3 filechooser.

• Pass the option 'fifo' to start a SCHED_FIFO thread
• Pass 'gtk' to have gtk be initialized.
• Pass 'fc' to initialize gtk and a file chooser dialog
• Pass 'sock' to simulate the netlink socket call that fails inside SSH

Note that the application will not actually display a window

Building

• simply call make
• After calling make you need to allow this application to use the real-time scheduler: sudo setcap cap_sys_nice+ep ./fifo_make

Running

Run ./fifo_make fifo, ./fifo_make sock, and then ./fifo_make fc

After about 30 seconds after calling ./fifo_make fc the ./fifo_make sock thread will hang.

You could also test this by trying to login to SSH, which will also hang if you server doesn't specify an IPv4 type.

Additionally, rather than call ./fifo_make fc you could open an Gtk3 application like gedit and then open a file browse menu.