* jialina01 ([email protected]) wrote:
> During an active background migraion, snapshot will trigger a
> segmentfault. As snapshot clears the "current_migration" struct
> and updates "to_dst_file" before it finds out that there is a
> migration task, Migration accesses the null pointer in
> "current_migration" struct and qemu crashes eventually.
>
> Signed-off-by: jialina01 <[email protected]>
> Signed-off-by: chaiwen <[email protected]>
> Signed-off-by: zhangyu <[email protected]>
Yes, that looks like an improvement, but is it enough?
With that change does qemu_savevm_state fail cleanly if attempted
during a migration? I suspect it will still try and do a snapshot,
because I don't see where it's checking the current state
(like the check in migrate_prepare that does a QERR_MIGRATIION_ACTIVE).
Dave
> ---
> migration/savevm.c | 14 +++++---------
> 1 file changed, 5 insertions(+), 9 deletions(-)
>
> diff --git a/migration/savevm.c b/migration/savevm.c
> index 2d10e45582..9cb97ca343 100644
> --- a/migration/savevm.c
> +++ b/migration/savevm.c
> @@ -1319,21 +1319,18 @@ static int qemu_savevm_state(QEMUFile *f, Error
> **errp)
> MigrationState *ms = migrate_get_current();
> MigrationStatus status;
>
> - migrate_init(ms);
> -
> - ms->to_dst_file = f;
> -
> if (migration_is_blocked(errp)) {
> - ret = -EINVAL;
> - goto done;
> + return -EINVAL;
> }
>
> if (migrate_use_block()) {
> error_setg(errp, "Block migration and snapshots are incompatible");
> - ret = -EINVAL;
> - goto done;
> + return -EINVAL;
> }
>
> + migrate_init(ms);
> + ms->to_dst_file = f;
> +
> qemu_mutex_unlock_iothread();
> qemu_savevm_state_header(f);
> qemu_savevm_state_setup(f);
> @@ -1355,7 +1352,6 @@ static int qemu_savevm_state(QEMUFile *f, Error **errp)
> error_setg_errno(errp, -ret, "Error while writing VM state");
> }
>
> -done:
> if (ret != 0) {
> status = MIGRATION_STATUS_FAILED;
> } else {
> --
> 2.13.2.windows.1
>
--
Dr. David Alan Gilbert / [email protected] / Manchester, UK
