migration/multifd: Join all multifd threads in order to avoid leaks

Current approach will only join threads that are still running.

For the threads not joined, resources or private memory are always kept in
the process space and never reclaimed before process end, and this risks
serious memory leaks.

This should usually not represent a big problem, since multifd migration
is usually just ran at most a few times, and after it succeeds there is
not much to be done before exiting the process.

Yet still, it should not hurt performance to join all of them.

Fixes: b5eea99ec2 ("migration: Add yank feature")
Reported-by: Li Xiaohui <xiaohli@redhat.com>
Signed-off-by: Leonardo Bras <leobras@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

diff --git a/migration/multifd.c b/migration/multifd.c
index 3dd569d0c9093718636558c8abe38bdac4d5bc19..840d5814e42e1cda763fa55f4eed786ca1d4e873 100644 (file)
--- a/migration/multifd.c
+++ b/migration/multifd.c
@@ -1030,8 +1030,9 @@ void multifd_load_cleanup(void)
              * however try to wakeup it without harm in cleanup phase.
              */
             qemu_sem_post(&p->sem_sync);
-            qemu_thread_join(&p->thread);
         }
+
+        qemu_thread_join(&p->thread);
     }
     for (i = 0; i < migrate_multifd_channels(); i++) {
         MultiFDRecvParams *p = &multifd_recv_state->params[i];