good example for gdb reverse execution

https://www.youtube.com/watch?v=PorfLSr3DDI&t=9m5s


https://sourceware.org/gdb/onlinedocs/gdb/Process-Record-and-Replay.html
record

https://sourceware.org/gdb/onlinedocs/gdb/Reverse-Execution.html#Reverse-Execution
reverse-continue
reverse-stepi

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