Liao Chang <[email protected]> writes: > + > +/* > + * xol_recycle_insn_slot - recycle a slot from the garbage collection list. > + */ > +static int xol_recycle_insn_slot(struct xol_area *area) > +{ > + struct uprobe_task *utask; > + int slot = UINSNS_PER_PAGE; > + > + rcu_read_lock(); > + list_for_each_entry_rcu(utask, &area->gc_list, gc) { > + /* > + * The utask associated slot is in-use or recycling when > + * utask associated slot_ref is not one. > + */ > + if (test_and_put_task_slot(utask)) { > + slot = utask->insn_slot; > + utask->insn_slot = UINSNS_PER_PAGE; > + clear_bit(slot, area->bitmap); > + atomic_dec(&area->slot_count); > + get_task_slot(utask);
Doesn't this need some annotation to make ThreadSanitizer happy? Would be good to have some commentary why doing so many write operations with merely a rcu_read_lock as protection is safe. It might be safer to put some write type operations under a real lock. Also it is unclear how the RCU grace period for utasks is enforced. -Andi
