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| author |   Dr. David Alan Gilbert <dgilbert@redhat.com> | 2019-09-13 17:35:07 +0100 |
|---|---|---|
| committer | Dr. David Alan Gilbert <dgilbert@redhat.com> | 2019-09-25 15:51:19 +0100 |
| commit | d46a4847ca868aaf537df2b87ce07dcbcad6a224 (patch) | |
| tree | 05605ee81a7c19d1ef22841d9350ed01902b71c4 /scripts/qapi/source.py | |
| parent | migration/rdma: Don't moan about disconnects at the end (diff) | |
| download | qemu-d46a4847ca868aaf537df2b87ce07dcbcad6a224.tar.xz qemu-d46a4847ca868aaf537df2b87ce07dcbcad6a224.zip | |
migration/rdma.c: Swap synchronize_rcu for call_rcu
This fixes a deadlock that can occur on the migration source after
a failed RDMA migration; as the source tries to cleanup it
clears a pair of pointers and uses synchronize_rcu to wait; this
is happening on the main thread. With the CPUs running
a CPU thread can be an rcu reader and attempt to grab the main lock
(kvm_handle_io->address_space_write->flatview_write->flatview_write_continue->
prepare_mmio_access->qemu_mutex_lock_iothread_impl)
Replace the synchronize_rcu with a call_rcu to postpone the freeing.
Fixes: 74637e6f08fceda98806 ("migration: implement bi-directional RDMA QIOChannel")
( https://bugzilla.redhat.com/show_bug.cgi?id=1746787 )
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20190913163507.1403-3-dgilbert@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Diffstat (limited to 'scripts/qapi/source.py')
0 files changed, 0 insertions, 0 deletions