Description of problem

After launched an android container based on kata, root user can't write/create file even the file owner is root with "drwxr-x--x" access right;

Expected result

root user can own the access right of whom the file owner is root;

Actual result

1. enter android container:
   31bc2e1d785a:/ # ls
   acct init.environ.rc property_contexts
   android-entry init.houdini.rc root
   bugreports init.logs.rc sbin
   cache init.multidroid.rc sdcard
   charger init.multidroid_cloud.rc seapp_contexts
   config init.multidroid_cloud.usb.rc selinux_version
   d init.rc sepolicy
   data init.usb.configfs.rc service_contexts
   default.prop init.usb.rc storage
   dev init.zygote32.rc sys
   etc init.zygote64_32.rc system
   file_contexts.bin ipc ueventd.multidroid_cloud.rc
   fstab.multidroid_cloud mnt ueventd.rc
   init oem vendor
   init.crashlogd.rc proc
   31bc2e1d785a:/ #

2. list the own/group owner/other user access right by "ls -l"
   31bc2e1d785a:/ # ls -l
   total 6136
   drwxr-xr-x 1 root root 17 2019-05-29 13:42 acct
   -rwxr-xr-x 1 root root 1266408 2018-11-15 07:24 android-entry
   lrwxrwxrwx 1 root root 50 2018-11-15 07:24 bugreports -> /data/user_de/0/com.android.shell/files/bugreports
   drwxr-xr-x 2 root root 6 2018-11-15 07:24 cache
   lrwxrwxrwx 1 root root 13 2018-11-15 07:24 charger -> /sbin/healthd
   drwxr-xr-x 2 root root 6 2018-11-15 07:24 config
   lrwxrwxrwx 1 root root 17 2018-11-15 07:24 d -> /sys/kernel/debug
   drwxr-x--x 34 root root 4096 2019-05-29 09:13 data
   -rw-r--r-- 1 root root 1160 2018-11-15 07:24 default.prop
   drwxr-xr-x 15 root root 2980 2019-05-29 13:42 dev
   drwxr-xr-x 1 root root 66 2019-05-29 13:42 etc
   -rw-r--r-- 1 root root 77090 2018-11-15 07:24 file_contexts.bin
   -rw-r--r-- 1 root root 113 2018-11-15 07:24 fstab.multidroid_cloud
   -rwxr-xr-x 1 root root 1468488 2018-11-15 07:24 init
   -rw-r--r-- 1 root root 647 2018-11-15 07:24 init.crashlogd.rc
   -rw-r--r-- 1 root root 887 2018-11-15 07:24 init.environ.rc
   -rw-r--r-- 1 root root 541 2018-11-15 07:24 init.houdini.rc
   -rw-r--r-- 1 root root 1557 2018-11-15 07:24 init.logs.rc
   -rwxr-xr-x 1 root root 1506 2018-11-15 07:24 init.multidroid.rc
   -rwxr-xr-x 1 root root 71 2018-11-15 07:24 init.multidroid_cloud.rc
   -rw-r--r-- 1 root root 4106 2018-11-15 07:24 init.multidroid_cloud.usb.rc
   -rwxr-xr-x 1 root root 27158 2018-11-15 07:24 init.rc
   -rw-r--r-- 1 root root 9283 2018-11-15 07:24 init.usb.configfs.rc
   -rwxr-xr-x 1 root root 5715 2018-11-15 07:24 init.usb.rc
   -rw-r--r-- 1 root root 411 2018-11-15 07:24 init.zygote32.rc
   -rw-r--r-- 1 root root 684 2018-11-15 07:24 init.zygote64_32.rc
   drwxr-xr-x 3 root root 20 2019-05-29 09:12 ipc
   drwxr-xr-x 10 root system 220 2019-05-29 13:42 mnt
   drwxr-xr-x 2 root root 6 2018-11-15 07:24 oem
   dr-xr-xr-x 84 root root 0 2019-05-29 13:42 proc
   -rw-r--r-- 1 root root 4745 2018-11-15 07:24 property_contexts
   drwxr-xr-x 2 root root 6 2018-11-15 07:24 root
   drwxr-xr-x 2 root root 65 2018-11-15 07:24 sbin
   lrwxrwxrwx 1 root root 21 2018-11-15 07:24 sdcard -> /storage/self/primary
   -rw-r--r-- 1 root root 758 2018-11-15 07:24 seapp_contexts
   -rw-r--r-- 1 root root 71 2018-11-15 07:24 selinux_version
   -rw-r--r-- 1 root root 178142 2018-11-15 07:24 sepolicy
   -rw-r--r-- 1 root root 11162 2018-11-15 07:24 service_contexts
   drwxr-xr-x 3 root root 60 2019-05-29 13:42 storage
   dr-xr-xr-x 11 root root 0 2019-05-29 13:42 sys
   drwxr-xr-x 17 root root 224 2018-11-15 07:24 system
   -rw-r--r-- 1 root root 272 2018-11-15 07:24 ueventd.multidroid_cloud.rc
   -rwxr-xr-x 1 root root 4853 2018-11-15 07:24 ueventd.rc
   lrwxrwxrwx 1 root root 14 2018-11-15 07:24 vendor -> /system/vendor

3. try to modify a file and report the error "sh: can't create test.txt: Read-only file system"
   31bc2e1d785a:/data # ls
   adb app-private drm misc_ce security user
   anr backup local misc_de ss user_de
   app bootchart lost+found ota system
   app-asec cache media ota_package system_ce
   app-ephemeral dalvik-cache mediadrm property system_de
   app-lib data misc resource-cache tombstones
   31bc2e1d785a:/data # echo 111 > test.txt
   sh: can't create test.txt: Read-only file system
   1|31bc2e1d785a:/data #
   1|31bc2e1d785a:/data # ls -l
   total 24
   drwx------ 2 root root 6 2019-05-29 09:13 adb
   drwxrwxr-x 2 root root 52 2019-05-29 09:13 anr
   drwxrwx--x 4 root root 63 2019-05-29 09:13 app
   drwx------ 2 root root 6 2019-05-29 09:13 app-asec
   drwxrwx--x 2 root root 6 2019-05-29 09:12 app-ephemeral
   drwxrwx--x 2 root root 6 2019-05-29 09:13 app-lib
   drwxrwx--x 2 root root 6 2019-05-29 09:13 app-private
   drwx------ 3 root root 62 2019-05-29 09:12 backup
   drwxr-xr-x 2 root root 6 2019-05-29 09:13 bootchart
   drwxrwx--- 5 root root 56 2019-05-29 09:13 cache
   drwxrwx--x 4 root root 31 2019-05-29 09:12 dalvik-cache
   drwxr-x--x 59 root root 4096 2019-05-29 09:13 data
   drwxrwx--- 2 root root 6 2019-05-29 09:13 drm
   drwxr-x--x 3 root root 17 2019-05-29 09:12 local
   drwxrwx--- 2 root root 6 2019-05-29 09:12 lost+found
   drwxrwx--- 4 root root 26 2019-05-29 09:13 media
   drwxrwx--- 2 root root 6 2019-05-29 09:13 mediadrm
   drwxrwx--x 30 root root 4096 2019-05-29 09:13 misc
   drwxrwx--x 3 root root 15 2019-05-29 09:13 misc_ce
   drwxrwx--x 3 root root 15 2019-05-29 09:13 misc_de
   drwxrwx--x 2 root root 6 2019-05-29 09:12 ota
   drwxrwx--- 2 root root 6 2019-05-29 09:13 ota_package
   drwx------ 2 root root 241 2019-05-29 09:13 property
   drwxrwx--x 2 root root 6 2019-05-29 09:13 resource-cache
   drwx--x--x 2 root root 6 2019-05-29 09:13 security
   drwx------ 2 root root 6 2019-05-29 09:13 ss
   drwxrwxr-x 14 root root 4096 2019-05-29 09:12 system
   drwxrwx--- 3 root root 15 2019-05-29 09:13 system_ce
   drwxrwx--- 3 root root 15 2019-05-29 09:12 system_de
   drwxrwxr-x 2 root root 206 2019-05-29 09:12 tombstones
   drwx--x--x 2 root root 6 2019-05-29 09:12 user
   drwx--x--x 3 root root 15 2019-05-29 09:12 user_de

By the way, if i run the same android container image based on runc or run other Linux container image based on kata, there is no such access issue.
I am not sure if there is related with 9pfs shared ro or build container rootfs to change it into read-only mode.
I will check and verify this issue by code debugging.

Kata version :1.7.0