mount -o remount,rw,sync /system

[emadhajjar]

When I run this command mount -o remount,rw,sync /system
System freezing and everything stop working.

[emadhajjar]

shell@android:/ # chmod 777 /data/local/tmp/rootme/nefarious.sh
shell@android:/ # echo /data/local/tmp/rootme/nefarious.sh | run-as
uid run-as 0
uid 0
no selinux?
shell@android:/ # Usage: mount [-r] [-w] [-o options] [-t type] device directory
: Read-only file system
: No such file or directory
: Read-only file system
: No such file or directoryn/su
: No such file or directoryn/su
: Read-only file system
shell@android:/ # shell@android:/ #

[energee]

Failing for me here too:

255|shell@android:/ $ mount -o remount,rw /system
mount: Operation not permitted

[zombiestruck]

Try using the one click, newly released.