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[PATCH 00/13] Reverse debugging
From: |
Pavel Dovgalyuk |
Subject: |
[PATCH 00/13] Reverse debugging |
Date: |
Fri, 26 Jun 2020 13:19:40 +0300 |
User-agent: |
StGit/0.17.1-dirty |
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
Acceptance tests intended to use the version of avocado framework, that
will be released after 25.06.20, because it includes significant
fixes of the remote GDB protocol.
The patches are available in the repository:
https://github.com/ispras/qemu/tree/rr-200626
---
Pavel Dovgaluk (13):
replay: provide an accessor for rr filename
qcow2: introduce icount field for snapshots
migration: introduce icount field for snapshots
iotests: update snapshot test for new output format
qapi: introduce replay.json for record/replay-related stuff
replay: introduce info hmp/qmp command
replay: introduce breakpoint at the specified step
replay: implement replay-seek command
replay: flush rr queue before loading the vmstate
gdbstub: add reverse step support in replay mode
gdbstub: add reverse continue support in replay mode
replay: describe reverse debugging in docs/replay.txt
tests/acceptance: add reverse debugging test
0 files changed
--
Pavel Dovgalyuk
- [PATCH 00/13] Reverse debugging,
Pavel Dovgalyuk <=
- [PATCH 08/13] replay: implement replay-seek command, Pavel Dovgalyuk, 2020/06/26
- [PATCH 10/13] gdbstub: add reverse step support in replay mode, Pavel Dovgalyuk, 2020/06/26
- [PATCH 06/13] replay: introduce info hmp/qmp command, Pavel Dovgalyuk, 2020/06/26
- [PATCH 03/13] migration: introduce icount field for snapshots, Pavel Dovgalyuk, 2020/06/26
- [PATCH 09/13] replay: flush rr queue before loading the vmstate, Pavel Dovgalyuk, 2020/06/26
- [PATCH 12/13] replay: describe reverse debugging in docs/replay.txt, Pavel Dovgalyuk, 2020/06/26
- [PATCH 13/13] tests/acceptance: add reverse debugging test, Pavel Dovgalyuk, 2020/06/26
- [PATCH 01/13] replay: provide an accessor for rr filename, Pavel Dovgalyuk, 2020/06/26
- [PATCH 02/13] qcow2: introduce icount field for snapshots, Pavel Dovgalyuk, 2020/06/26
- [PATCH 04/13] iotests: update snapshot test for new output format, Pavel Dovgalyuk, 2020/06/26