Re: [libvirt-users] error : virHashForEach:597 : Hash operation not allowed during iteration

Vincent Bernat
Wed, 04 Apr 2018 15:00:48 -0000

❦  4 avril 2018 16:21 +0200, Vincent Bernat <bernat@luffy.cx> :

>> You can do that locally, but as a patch it's very unlikely to be
>> accepted upstream because we've introduced RW locks to be able to
access
>> domain list from multiple threads.
>
> Looking a bit more, the whole "iterating" bit is currently
> unsafe. First, it is racy since it's "check then take". Two
threads may
> check the value is false and start iterating both. Moreover, at some
> places, it is not set, for example in virHashAddOrUpdateEntry(). So, it
> would be possible to call this function and during the update to iterate
> over the hash. This seems to be prevented only by callers using RW
> lock. So, it seems we can just remove this "iterating" bool and
just
> check all users of these functions are using the appropriate lock.

My bad, I didn't see the use of table->current...
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