> +static inline void debug_rcu_head_callback(struct rcu_head *rhp) > +{ > + if (unlikely(!rhp->func)) > + mem_dump_obj(rhp); > +} > + The mm/util.c definition of mem_dump_object() says: * This function uses pr_cont(), so that the caller is expected to have * printed out whatever preamble is appropriate. so this needs to call pr_alert() or pr_err() before that to explain what is being printed (with no \n), like these: kernel/rcu/rcutorture.c: pr_alert("mem_dump_obj(%px):", &rhp); kernel/rcu/rcutorture.c: mem_dump_obj(&rhp); ... kernel/rcu/tree.c: pr_err("%s(): Double-freed CB %p->%pS()!!! ", __func__, head, head->func); kernel/rcu/tree.c: mem_dump_obj(head);