It's not safe to call qemu_file_shutdown() on the to_dst_file without
first checking for the file's presence under the lock. The cleanup of
this file happens at postcopy_pause() and migrate_fd_cleanup() which
are not necessarily running in the same thread as migrate_fd_cancel().
Reviewed-by: Peter Xu <pet...@redhat.com>
Signed-off-by: Fabiano Rosas <faro...@suse.de>
---
migration/migration.c | 18 +++++++++++-------
1 file changed, 11 insertions(+), 7 deletions(-)
diff --git a/migration/migration.c b/migration/migration.c
index 15b7258bb2..6e09463466 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -1246,7 +1246,7 @@ static void migrate_fd_error(MigrationState *s, const
Error *error)
static void migrate_fd_cancel(MigrationState *s)
{
int old_state ;
- QEMUFile *f = migrate_get_current()->to_dst_file;
+
trace_migrate_fd_cancel();
WITH_QEMU_LOCK_GUARD(&s->qemu_file_lock) {
@@ -1272,11 +1272,13 @@ static void migrate_fd_cancel(MigrationState *s)
* If we're unlucky the migration code might be stuck somewhere in a
* send/write while the network has failed and is waiting to timeout;
* if we've got shutdown(2) available then we can force it to quit.
- * The outgoing qemu file gets closed in migrate_fd_cleanup that is
- * called in a bh, so there is no race against this cancel.
*/
- if (s->state == MIGRATION_STATUS_CANCELLING && f) {
- qemu_file_shutdown(f);
+ if (s->state == MIGRATION_STATUS_CANCELLING) {
+ WITH_QEMU_LOCK_GUARD(&s->qemu_file_lock) {
+ if (s->to_dst_file) {
+ qemu_file_shutdown(s->to_dst_file);
+ }
+ }
}
if (s->state == MIGRATION_STATUS_CANCELLING && s->block_inactive) {
Error *local_err = NULL;
@@ -1536,12 +1538,14 @@ void qmp_migrate_pause(Error **errp)
{
MigrationState *ms = migrate_get_current();
MigrationIncomingState *mis = migration_incoming_get_current();
- int ret;
+ int ret = 0;
if (ms->state == MIGRATION_STATUS_POSTCOPY_ACTIVE) {
/* Source side, during postcopy */
qemu_mutex_lock(&ms->qemu_file_lock);
- ret = qemu_file_shutdown(ms->to_dst_file);
+ if (ms->to_dst_file) {
+ ret = qemu_file_shutdown(ms->to_dst_file);
+ }
qemu_mutex_unlock(&ms->qemu_file_lock);
if (ret) {
error_setg(errp, "Failed to pause source migration");
--
2.35.3
