[Maria-developers] MDEV-18734 ASAN heap-use-after-free in my_strnxfrm_simple_internal upon update on versioned partitioned table

Hi, Sergei! ha_partition::handle_ordered_index_scan() stores records in m_ordered_rec_buffer. Then TABLE::update_virtual_fields() updates blob buffer and frees the old one. Then ha_partition::return_top_record() returns record from m_ordered_rec_buffer with stale blob pointer. What should we do with this? I propose to duplicate blob buffer when record gets into m_ordered_rec_buffer. More details can be found here: https://github.com/tempesta-tech/mariadb/issues/581 -- All the best, Aleksey Midenkov @midenok