On Tue, 2017-02-07 at 19:46 -0800, Nicholas A. Bellinger wrote: > On Tue, 2017-02-07 at 15:12 -0800, Christoph Hellwig wrote: > > And the real patch after compile fixing it is here of course: > > > > Getting rid of the extra se_node_acl->acl_free_comp seems to make sense > here.. > > The only potential issue is if returning from configfs syscall > rmdir /sys/kernel/config/target/$FABRIC/$WWN/$TPGT/acls/$INITIATOR/ > before se_node_acl memory is released has implications when the > underlying ../$WWN/$TPGT/ is removed immediately after. > > In any event, I'll verify this patch with the original test case and use > it instead if everything looks OK. Ok, I remember why se_node_acl->acl_free_comp is needed now.. The issue is when se_node_acl is being explicitly removed from configfs while se_sessions associated with se_node_acl are still active. The se_node_acl->acl_group configfs_group_operations->drop_item() callback must block until all associated se_sessions have done their target_put_nacl() and completed se_node_acl->acl_free_comp, otherwise there is nothing preventing parent config_groups of se_node_acl from being removed while the se_sessions are still active. That said, dropping the unnecessary list_del_init() usage, but otherwise keeping the patch as-is.
