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[Qemu-devel] [PATCH v7 16/22] replay: avoid recursive call of checkpoint
From: |
Pavel Dovgalyuk |
Subject: |
[Qemu-devel] [PATCH v7 16/22] replay: avoid recursive call of checkpoints |
Date: |
Tue, 27 Feb 2018 12:53:05 +0300 |
User-agent: |
StGit/0.17.1-dirty |
This patch adds a flag which denies recursive call of replay_checkpoint
function. Checkpoints may be accompanied by the hardware events. When event
is processed, virtual device may invoke timer modification functions that
also invoke the checkpoint function. This leads to infinite loop.
Signed-off-by: Pavel Dovgalyuk <address@hidden>
---
replay/replay.c | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)
diff --git a/replay/replay.c b/replay/replay.c
index 60659c9..d5c3a66 100644
--- a/replay/replay.c
+++ b/replay/replay.c
@@ -176,13 +176,24 @@ void replay_shutdown_request(ShutdownCause cause)
bool replay_checkpoint(ReplayCheckpoint checkpoint)
{
bool res = false;
+ static bool in_checkpoint;
assert(EVENT_CHECKPOINT + checkpoint <= EVENT_CHECKPOINT_LAST);
- replay_save_instructions();
if (!replay_file) {
return true;
}
+ if (in_checkpoint) {
+ /* If we are already in checkpoint, then there is no need
+ for additional synchronization.
+ Recursion occurs when HW event modifies timers.
+ Timer modification may invoke the checkpoint and
+ proceed to recursion. */
+ return true;
+ }
+ in_checkpoint = true;
+
+ replay_save_instructions();
if (replay_mode == REPLAY_MODE_PLAY) {
g_assert(replay_mutex_locked());
@@ -204,6 +215,7 @@ bool replay_checkpoint(ReplayCheckpoint checkpoint)
res = true;
}
out:
+ in_checkpoint = false;
return res;
}
- [Qemu-devel] [PATCH v7 06/22] replay: fixed replay_enable_events, (continued)
- [Qemu-devel] [PATCH v7 06/22] replay: fixed replay_enable_events, Pavel Dovgalyuk, 2018/02/27
- [Qemu-devel] [PATCH v7 07/22] replay: fix save/load vm for non-empty queue, Pavel Dovgalyuk, 2018/02/27
- [Qemu-devel] [PATCH v7 08/22] replay: added replay log format description, Pavel Dovgalyuk, 2018/02/27
- [Qemu-devel] [PATCH v7 09/22] replay: save prior value of the host clock, Pavel Dovgalyuk, 2018/02/27
- [Qemu-devel] [PATCH v7 11/22] replay/replay-internal.c: track holding of replay_lock, Pavel Dovgalyuk, 2018/02/27
- [Qemu-devel] [PATCH v7 10/22] replay/replay.c: bump REPLAY_VERSION again, Pavel Dovgalyuk, 2018/02/27
- [Qemu-devel] [PATCH v7 12/22] replay: make locking visible outside replay code, Pavel Dovgalyuk, 2018/02/27
- [Qemu-devel] [PATCH v7 13/22] replay: push replay_mutex_lock up the call tree, Pavel Dovgalyuk, 2018/02/27
- [Qemu-devel] [PATCH v7 14/22] replay: don't destroy mutex at exit, Pavel Dovgalyuk, 2018/02/27
- [Qemu-devel] [PATCH v7 15/22] replay: check return values of fwrite, Pavel Dovgalyuk, 2018/02/27
- [Qemu-devel] [PATCH v7 16/22] replay: avoid recursive call of checkpoints,
Pavel Dovgalyuk <=
- [Qemu-devel] [PATCH v7 17/22] scripts/replay-dump.py: replay log dumper, Pavel Dovgalyuk, 2018/02/27
- [Qemu-devel] [PATCH v7 18/22] replay: don't process async events when warping the clock, Pavel Dovgalyuk, 2018/02/27
- [Qemu-devel] [PATCH v7 19/22] replay: save vmstate of the asynchronous events, Pavel Dovgalyuk, 2018/02/27
- [Qemu-devel] [PATCH v7 20/22] replay: don't drain/flush bdrv queue while RR is working, Pavel Dovgalyuk, 2018/02/27
- [Qemu-devel] [PATCH v7 21/22] replay: update documentation, Pavel Dovgalyuk, 2018/02/27
- [Qemu-devel] [PATCH v7 22/22] tcg: fix cpu_io_recompile, Pavel Dovgalyuk, 2018/02/27