Deterministic debugging with rr record-replay. Use when debugging crashes, ASAN faults, or when reverse execution is needed. Provides reverse-next, reverse-step, reverse-continue commands and crash trace extraction.
rr provides deterministic record-replay debugging with full reverse execution capabilities.
rr record <program> [args]rr replay (enters gdb interface with reverse execution)All standard gdb commands work, plus reverse variants:
reverse-next / rn: Step back over function callsreverse-step / rs: Step back into functionsreverse-continue / rc: Continue backward to previous breakpointreverse-stepi / rsi: Step back one instructionreverse-nexti / rni: Step back over one instructionAfter rr record <crashing-program>:
rr replay
# In gdb:
reverse-next 100 # Go back 100 steps (adjust N as needed)
# Now step forward to see execution leading to crash:
next
next
...
After rr record <asan-program>:
rr replay
# In gdb:
bt # View stack trace
up # Issue "up" commands until last app frame (before ASAN runtime)
break *$pc # Set breakpoint at that location
reverse-continue # Go back to last app instruction before ASAN
# Now step forward to see execution leading to fault:
next
next
...
Standard gdb commands work at any point:
print <var>: Print variable valueprint *<ptr>: Dereference pointerx/<format> <address>: Examine memory
x/10xb <addr>: 10 bytes in hexx/s <addr>: String at addressinfo locals: Show local variablesinfo args: Show function argumentslist: Show source code around current locationdisassemble: Show assembly around current locationlayout src: TUI source viewlayout asm: TUI assembly viewset disassemble-next-line on: Show assembly with each stepUse scripts/crash_trace.py to automatically extract execution trace before crash.