Hi Menglong,
Sorry, one more thing.
> @@ -260,14 +263,12 @@ static int fprobe_entry(struct ftrace_graph_ent *trace,
> struct fgraph_ops *gops,
> if (WARN_ON_ONCE(!fregs))
> return 0;
>
> - first = node = find_first_fprobe_node(func);
> - if (unlikely(!first))
> - return 0;
> -
> + rcu_read_lock();
Actually, we don't need these rcu_read_lock() in this function, because
the caller function_graph_enter_regs() uses ftrace_test_recursion_trylock()
which disables preemption. Thus we don't need to do this again here.
> + head = rhltable_lookup(&fprobe_ip_table, &func, fprobe_rht_params);
> reserved_words = 0;
> - hlist_for_each_entry_from_rcu(node, hlist) {
> + rhl_for_each_entry_rcu(node, pos, head, hlist) {
> if (node->addr != func)
> - break;
> + continue;
> fp = READ_ONCE(node->fp);
> if (!fp || !fp->exit_handler)
> continue;
> @@ -278,17 +279,19 @@ static int fprobe_entry(struct ftrace_graph_ent *trace,
> struct fgraph_ops *gops,
> reserved_words +=
> FPROBE_HEADER_SIZE_IN_LONG +
> SIZE_IN_LONG(fp->entry_data_size);
> }
> - node = first;
> + rcu_read_unlock();
> if (reserved_words) {
> fgraph_data = fgraph_reserve_data(gops->idx, reserved_words *
> sizeof(long));
> if (unlikely(!fgraph_data)) {
> - hlist_for_each_entry_from_rcu(node, hlist) {
> + rcu_read_lock();
Ditto.
> + rhl_for_each_entry_rcu(node, pos, head, hlist) {
> if (node->addr != func)
> - break;
> + continue;
> fp = READ_ONCE(node->fp);
> if (fp && !fprobe_disabled(fp))
> fp->nmissed++;
> }
> + rcu_read_unlock();
> return 0;
> }
> }
Thank you,
--
Masami Hiramatsu (Google) <[email protected]>
