Redox OS Microkernel
Debugging the redox kernel
Running qemu with the
-s flag will set up qemu to listen on port 1234 for
a gdb client to connect to it. To debug the redox kernel run.
make qemu gdb=yes
This will start a VM with and listen on port 1234 for a gdb or lldb client.
If you are going to use gdb, run the following to load debug symbols and connect to your running kernel.
(gdb) symbol-file build/kernel.sym (gdb) target remote localhost:1234
If you are going to use lldb, run the following to start debugging.
(lldb) target create -s build/kernel.sym build/kernel (lldb) gdb-remote localhost:1234
After connecting to your kernel you can set some interesting breakpoints and
the process. See your debuggers man page for more information on useful commands to run.
When trying to access a slice, always use the
common::GetSlicetrait and the
.get_slice()method to get a slice without causing the kernel to panic. The problem with slicing in regular Rust, e.g.
foo[a..b], is that if someone tries to access with a range that is out of bounds of an array/string/slice, it will cause a panic at runtime, as a safety measure. Same thing when accessing an element.
foo[n]and try to cover for the possibility of
Option::None. Doing the regular way may work fine for applications, but never in the kernel. No possible panics should ever exist in kernel space, because then the whole OS would just stop working.
If you receive a kernel panic in QEMU, use
pkill qemu-systemto kill the frozen QEMU process.