Re: [Libguestfs] nbdkit worker thread shutdown

On 05/05/22 09:59, Nikolaus Rath wrote: > Hello, > > When nbdkit calls a plugin's unload() method, is it guaranteed that all > pending requests have been handled (and all worker threads exited)? > > (I would have expected this to be the case, but I'm getting errors from > threads accessing data that my unload() handler frees, so I wanted to > confirm my assumption). From <https://libguestfs.org/nbdkit-plugin.3.html>;: .cleanup is called once after all connections have been closed, prior to unloading the plugin from memory. This is only called if .after_fork succeeded earlier (even in cases where nbdkit did not fork but is running in the foreground), which makes it a good place to gracefully end any background threads. So I would think you need to either join all threads in .cleanup (at the latest), waiting for them to drain any pending work, or cancel them (with appropriate cancellation handlers in the background threads).