On 03/10/20 19:12, Pavel Dovgalyuk wrote: > GDB remote protocol supports reverse debugging of the targets. > It includes 'reverse step' and 'reverse continue' operations. > The first one finds the previous step of the execution, > and the second one is intended to stop at the last breakpoint that > would happen when the program is executed normally. > > Reverse debugging is possible in the replay mode, when at least > one snapshot was created at the record or replay phase. > QEMU can use these snapshots for travelling back in time with GDB. > > Running the execution in replay mode allows using GDB reverse debugging > commands: > - reverse-stepi (or rsi): Steps one instruction to the past. > QEMU loads on of the prior snapshots and proceeds to the desired > instruction forward. When that step is reaches, execution stops. > - reverse-continue (or rc): Runs execution "backwards". > QEMU tries to find breakpoint or watchpoint by loaded prior snapshot > and replaying the execution. Then QEMU loads snapshots again and > replays to the latest breakpoint. When there are no breakpoints in > the examined section of the execution, QEMU finds one more snapshot > and tries again. After the first snapshot is processed, execution > stops at this snapshot. > > The set of patches include the following modifications: > - gdbstub update for reverse debugging support > - functions that automatically perform reverse step and reverse > continue operations > - hmp/qmp commands for manipulating the replay process > - improvement of the snapshotting for saving the execution step > in the snapshot parameters > - avocado-based acceptance tests for reverse debugging > > The patches are available in the repository: > https://github.com/ispras/qemu/tree/rr-200901 > > v7 changes: > - updated snapshot info output format > - fixed qcow2 snapshot-related tests
Sorry, I'm still seeing a failure timeout 15 /home/travis/build/bonzini/qemu/build/qemu-system-aarch64 -monitor none -display none -chardev file,path=memory-replay.out,id=output -icount shift=5,rr=replay,rrfile=record.bin -M virt -cpu max -display none -semihosting-config enable=on,target=native,chardev=output -kernel memory qemu-system-aarch64: terminating on signal 15 from pid 38312 (timeout) https://travis-ci.com/gitlab/bonzini/qemu/jobs/395029273 Paolo
