aio_context should be locked in the similar way as was done in QMP
snapshot creation in the other case there are a lot of possible
troubles if native AIO mode is enabled for disk.
- the command can hang (HMP thread) with missed wakeup (the operation is
actually complete)
io_submit
ioq_submit
laio_submit
raw_aio_submit
raw_aio_readv
bdrv_co_io_em
bdrv_co_readv_em
bdrv_aligned_preadv
bdrv_co_do_preadv
bdrv_co_do_readv
bdrv_co_readv
qcow2_co_readv
bdrv_aligned_preadv
bdrv_co_do_pwritev
bdrv_rw_co_entry
- QEMU can assert in coroutine re-enter
__GI_abort
qemu_coroutine_enter
bdrv_co_io_em_complete
qemu_laio_process_completion
qemu_laio_completion_bh
aio_bh_poll
aio_dispatch
aio_poll
iothread_run
AioContext lock is reqursive. Thus nested locking should not be a problem.
Signed-off-by: Denis V. Lunev <[email protected]>
CC: Stefan Hajnoczi <[email protected]>
CC: Paolo Bonzini <[email protected]>
CC: Juan Quintela <[email protected]>
CC: Amit Shah <[email protected]>
---
block/snapshot.c | 5 +++++
migration/savevm.c | 7 +++++++
2 files changed, 12 insertions(+)
diff --git a/block/snapshot.c b/block/snapshot.c
index 89500f2..f6fa17a 100644
--- a/block/snapshot.c
+++ b/block/snapshot.c
@@ -259,6 +259,9 @@ void bdrv_snapshot_delete_by_id_or_name(BlockDriverState
*bs,
{
int ret;
Error *local_err = NULL;
+ AioContext *aio_context = bdrv_get_aio_context(bs);
+
+ aio_context_acquire(aio_context);
ret = bdrv_snapshot_delete(bs, id_or_name, NULL, &local_err);
if (ret == -ENOENT || ret == -EINVAL) {
@@ -267,6 +270,8 @@ void bdrv_snapshot_delete_by_id_or_name(BlockDriverState
*bs,
ret = bdrv_snapshot_delete(bs, NULL, id_or_name, &local_err);
}
+ aio_context_release(aio_context);
+
if (ret < 0) {
error_propagate(errp, local_err);
}
diff --git a/migration/savevm.c b/migration/savevm.c
index dbcc39a..83d2efa 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -1289,6 +1289,7 @@ void hmp_savevm(Monitor *mon, const QDict *qdict)
struct tm tm;
const char *name = qdict_get_try_str(qdict, "name");
Error *local_err = NULL;
+ AioContext *aio_context;
/* Verify if there is a device that doesn't support snapshots and is
writable */
bs = NULL;
@@ -1320,6 +1321,9 @@ void hmp_savevm(Monitor *mon, const QDict *qdict)
}
vm_stop(RUN_STATE_SAVE_VM);
+ aio_context = bdrv_get_aio_context(bs);
+ aio_context_acquire(aio_context);
+
memset(sn, 0, sizeof(*sn));
/* fill auxiliary fields */
@@ -1378,6 +1382,8 @@ void hmp_savevm(Monitor *mon, const QDict *qdict)
}
the_end:
+ aio_context_release(aio_context);
+
if (saved_vm_running) {
vm_start();
}
