If anyone is curious about what this would look like on a whole-system level, there is a series of patches [1] to QEMU that enables deterministic replay and reverse execution (i.e., step backward in gdb).

One can also use PANDA [2], but it doesn't currently support the gdb interface in replay mode.

[1] http://lists.nongnu.org/archive/html/qemu-devel/2014-12/msg0... [2] https://github.com/moyix/panda