On 07/11, Peter Zijlstra wrote:

  uprobe_free_stage1
    call_srcu(&uretprobe_srcu, &uprobe->rcu, uprobe_free_stage2);

  put_uprobe()
    if (refcount_dec_and_test)
      call_srcu(&uprobes_srcu, &uprobe->rcu, uprobe_free_stage1);


So my thinking was since we take uretprobe_srcu *inside* uprobe_srcu,

Ah, indeed! Somehow misread the change in put_uprobe() as if it
uses call_rcu(uretprobe_srcu).

Thanks,

Oleg.