在ubuntu下用find搜索时, 显示Operation not permitted 是怎么回事啊?root帐号

root@546c4db1ce22:/# find / -name httpd.conf

显示结果:
find: '/proc/1/map_files': Operation not permitted
find: '/proc/3474/map_files': Operation not permitted
find: '/proc/3476/map_files': Operation not permitted
find: '/proc/3477/map_files': Operation not permitted
find: '/proc/3540/map_files': Operation not permitted

我也有这个问题,你解决了没