Re: [PATCH] util: workaround libxml2 lack of thread safe initialization

On Mon, Jun 23, 2025 at 12:02:31 +0100, Daniel P. Berrangé via Devel wrote: > From: Daniel P. Berrangé <berrange(a)redhat.com&gt; > > The main XML parser code global initializer historically had a mutex > protecting it, and more recently uses a pthread_once. The RelaxNG > code, however, relies on three other global initializers that are > not thread safe, just relying on setting an integer "initialized" > flag. > > Calling the relevant initializers from libvirt in a protected global > initializer will protect libvirt's own concurrent usage, however, it > cannot protect against other libraries loaded in process that might > be using libxml2's schema code. Fortunately: > > * The chances of other loaded non-libvirt code using libxml is > relatively low > * The chances of other loaded non-libvirt code using the schema > validation / catalog functionality inside libxml is even > lower > * The chances of both libvirt and the non-libvirt usage having > their *1st* usage of libxml2 be concurrent is tiny Additionaly IIUC this could be problem only when using the embedded driver mode as we don't use libxml2 in the exported API