[PATCH 0/5] migration/multifd: Fix channel creation vs. cleanup races

[Fabiano Rosas]

Hi,

This contains 2 patches from my previous series addressing the
p->running misuse and the TLS thread leak and 3 new patches to fix the
cleanup-while-creating-threads race.

For the p->running I'm keeping the idea from the other series to
remove p->running and use a more narrow p->thread_created flag. This
flag is used only inform whether the thread has been created so we can
join it.

For the cleanup race I have moved some code around and added a
semaphore to make multifd_save_setup() only return once all channel
creation tasks have started.

The idea is that after multifd_save_setup() returns, no new creations
are in flight and the p->thread_created flags will never change again,
so they're enough to cause the cleanup code to wait for the threads to
join.

CI run: https://gitlab.com/farosas/qemu/-/pipelines/1162798843

@Peter: I can rebase this on top of your series once we decide about
it.

Fabiano Rosas (5):
  migration/multifd: Join the TLS thread
  migration/multifd: Remove p->running
  migration/multifd: Move multifd_save_setup error handling in to the
    function
  migration/multifd: Move multifd_save_setup into migration thread
  migration/multifd: Add a synchronization point for channel creation

 migration/migration.c |  14 ++---
 migration/multifd.c   | 129 ++++++++++++++++++++++++------------------
 migration/multifd.h   |  11 ++--
 3 files changed, 83 insertions(+), 71 deletions(-)

-- 
2.35.3