[PATCH 02/26] migration/multifd: Protect accesses to migration_threads

[Fabiano Rosas]

Juan Quintela <quintela at redhat.com> writes:

> From: Fabiano Rosas <farosas at suse.de>
>
> This doubly linked list is common for all the multifd and migration
> threads so we need to avoid concurrent access.
>
> Add a mutex to protect the data from concurrent access. This fixes a
> crash when removing two MigrationThread objects from the list at the
> same time during cleanup of multifd threads.
>
> Fixes: 671326201d ("migration: Introduce interface query-migrationthreads")
> Signed-off-by: Fabiano Rosas <farosas at suse.de>
> Reviewed-by: Peter Xu <peterx at redhat.com>
> Reviewed-by: Juan Quintela <quintela at redhat.com>
> Message-Id: <20230607161306.31425-3-farosas at suse.de>
> Signed-off-by: Juan Quintela <quintela at redhat.com>

Hi Juan,

What about re-enabling the /multifd/tcp/plain/cancel test? You had
mentioned that something else was needed, but never said exactly
what...

I've been doing a lot of migration work recently and all of my branches
have this change and the cancel test enabled. No issues so far.