Merge pull request #94 from python-discord/recursive-remove-cgroups

Remove all child cgroups before removing parents

snekbox/nsjail.py

@@ -224,6 +224,18 @@ def python3(self, code: str, *args) -> CompletedProcess:
 
         log.info(f"nsjail return code: {returncode}")
 
+        # If we hit a cgroup limit then there is a chance the nsjail cgroups did not
+        # get removed. If we don't remove them then when we try remove the parents
+        # we will get a "Device or resource busy" error.
+
+        children = []
+
+        children.extend(Path(self.config.cgroup_mem_mount, cgroup).glob("NSJAIL.*"))
+        children.extend(Path(self.config.cgroup_pids_mount, cgroup).glob("NSJAIL.*"))
+
+        for child in children:
+            child.rmdir()
+
         # Remove the dynamically created cgroups once we're done
         Path(self.config.cgroup_mem_mount, cgroup).rmdir()
         Path(self.config.cgroup_pids_mount, cgroup).rmdir()