[Android Software/Hacking General [Developers Only]] Pachacouti:
I then do:

Armor_X5_Q:/ # ls -l `which su`

total 1608

dr-xr-xr-x 4 root root 0 2021-09-27 13:00 acct

drwxr-xr-x 2 root root 40 2021-09-27 13:00 apex

lrwxrwxrwx 1 root root 11 2021-09-10 01:30 bin -> /system/bin

lrwxrwxrwx 1 root root 50 2021-09-10 01:30 bugreports -> /data/use

r_de/0/com.android.shell/files/bugreports

drwxrwx--- 6 system cache 4096 2010-01-01 00:03 cache

lrwxrwxrwx 1 root root 19 2021-09-10 01:30 charger -> /system/bin/

charger

drwxr-xr-x 4 root root 0 1970-01-01 00:00 config

lrwxrwxrwx 1 root root 17 2021-09-10 01:30 d -> /sys/kernel/debug

drwxrwx--x 55 system system 4096 2021-09-27 12:25 data

drwxr-xr-x 2 root root 0 2021-09-10 01:30 debug_ramdisk

lrwxrwxrwx 1 root root 12 2021-09-10 01:30 default.prop -> prop.de

fault

drwxr-xr-x 19 root root 3540 2021-09-27 13:00 dev

lrwxrwxrwx 1 root root 11 2021-09-10 01:30 etc -> /system/etc

drwxrwxrwx 13 root root 32768 1970-01-01 00:00 external_sd

-rw-r--r-- 1 root root 46380 2021-09-10 01:34 file_contexts

-rw-r--r-- 1 root root 865607 2021-09-10 01:30 file_contexts.bin

lrwxrwxrwx 1 root root 16 2021-09-10 01:30 init -> /system/bin/ini

t

-rwxr-x--- 1 root root 7073 2021-09-10 01:30 init.rc

-rwxr-x--- 1 root root 103 2021-09-10 01:30 init.recovery.hlthchrg.

rc

-rwxr-x--- 1 root root 58 2021-09-10 01:30 init.recovery.ldconfig.

rc

-rwxr-x--- 1 root root 312 2021-09-10 01:30 init.recovery.logd.rc

-rwxr-x--- 1 root root 8824 2021-09-10 02:14 init.recovery.microtrus

t.rc

-rwxr-x--- 1 root root 3686 2021-09-10 02:00 init.recovery.mt6762.rc

-rwxrwx--- 1 root root 854 2021-08-28 14:20 init.recovery.prepdecry

pt.rc

-rwxr-x--- 1 root root 213 2021-09-10 01:30 init.recovery.service.r

c

-rwxr-x--- 1 root root 7862 2021-09-10 01:30 init.recovery.usb.rc

drwxr-xr-x 3 root root 0 2021-09-10 01:30 license

drwxr-xr-x 5 root system 100 2021-09-27 13:00 mnt

drwxrwx--x 6 system system 4096 2021-01-01 09:33 nvcfg

drwxrwx--x 8 root system 4096 2021-01-01 08:06 nvdata

drwxr-xr-x 2 root root 0 2021-09-10 01:30 odm

-rw-r--r-- 1 root root 0 2021-09-10 01:30 odm_file_contexts

-rw-r--r-- 1 root root 0 2021-09-10 01:30 odm_property_contexts

drwxr-xr-x 2 root root 0 2021-09-10 01:30 oem

drwxrwx--x 5 system system 4096 2021-01-01 09:33 persist

-rw-r--r-- 1 root root 32079 2021-09-10 01:30 plat_file_contexts

-rw-r--r-- 1 root root 9476 2021-09-10 01:30 plat_property_contexts

dr-xr-xr-x 359 root root 0 1970-01-01 00:00 proc

drwxr-xr-x 12 root root 4096 2009-01-01 00:00 product

-rw-r--r-- 1 root root 0 2021-09-10 01:30 product_file_contexts

-rw-r--r-- 1 root root 0 2021-09-10 01:30 product_property_contex

ts

lrwxrwxrwx 1 root root 24 2021-09-10 01:30 product_services -> /sy

stem/product_services

-rw-r--r-- 1 root root 7414 2021-09-10 01:48 prop.default

drwxrwx--- 4 system system 4096 2010-01-01 00:10 protect_f

drwxrwx--- 4 system system 4096 2010-01-01 00:10 protect_s

-rw-r--r-- 1 root root 0 2021-09-10 01:30 relink_binaries-timesta

mp

-rw-r--r-- 1 root root 0 2021-09-10 01:30 relink_libraries-timest

amp

drwxr-xr-x 3 root root 0 2021-09-10 01:30 res

drwx------ 2 root root 0 2020-06-05 06:41 root

drwxr-x--- 2 root root 0 2021-09-10 01:30 sbin

drwxrwx--- 13 media_rw media_rw 4096 2021-09-27 13:06 sdcard

-rw-r--r-- 1 root root 465178 2021-09-10 01:30 sepolicy

drwxr-xr-x 2 root root 0 2021-09-27 13:00 sideload

drwxr-x--x 2 root root 0 2021-09-10 01:30 storage

dr-xr-xr-x 14 root root 0 2021-09-27 13:00 sys

drwxr-xr-x 7 root root 0 2021-09-27 13:09 system

drwxr-xr-x 21 root root 4096 2009-01-01 00:00 system_root

drwxrwxr-x 2 root shell 120 2021-09-27 13:07 tmp

drwxr-xr-x 5 root root 0 2021-09-10 01:55 twres

-rw-r--r-- 1 root root 0 2021-09-10 01:30 twrp_ramdisk-timestamp

-rw-r--r-- 1 root root 5900 2021-09-10 02:03 ueventd.mt6762.rc

-rw-r--r-- 1 root root 2969 2021-09-10 02:02 ueventd.rc

drwxrwxrwx 2 root root 0 2021-09-27 13:01 usbotg

drwxr-xr-x 14 root shell 4096 2009-01-01 00:00 vendor

-rw-r--r-- 1 root root 7759 2021-09-10 01:30 vendor_file_contexts

-rw-r--r-- 1 root root 218 2021-09-10 01:30 vendor_property_context

s

-rw-r--r-- 1 root root 0 2021-09-10 01:30 vendor_service_contexts

Armor_X5_Q:/ #

Edit:

drwxrwx--- 4 system system 4096 2010-01-01 00:10 protect_f

drwxrwx--- 4 system system 4096 2010-01-01 00:10 protect_s

Why dm-1, 2, 3, cant be mounted even in root.