not going to have an "unlimited" in event_trigger_print

[chensong2000]

We are not going to have an "unlimited" here. I think the count should be
the number of objects we can trace.

https://lore.kernel.org/all/20221017155829.7e8d4812@gandalf.local.home/

[chensong2000]

echo 'objtrace:+0x38(+0x8($arg1)):string[7] if comm == "cat"' > ./events/kprobes/p_vfs_open_0/trigger
这种格式可以，但在get_object_value会出错误，多走了一次FETCH_OP_DEREF:分支，这样取地址会出错，正在查。
PS：[7]在trace probe里表示为parg->count，code->op 会等于FETCH_OP_LP_ARRAY，在get_object_value没有处理（参照process_fetch_insn_bottom）