I found some security flaws on friendlywrt kernel debug .
7.332820] ********************************************************************
[ 7.332826] ** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **
[ 7.332832] ** **
[ 7.332838] ** WRITEABLE clk DebugFS SUPPORT HAS BEEN ENABLED IN THIS KERNEL **
[ 7.332844] ** **
[ 7.332849] ** This means that this kernel is built to expose clk operations **
[ 7.332854] ** such as parent or rate setting, enabling, disabling, etc. **
[ 7.332859] ** to userspace, which may compromise security on your system. **
[ 7.332864] ** **
[ 7.332869] ** If you see this message and you are not debugging the **
[ 7.332874] ** kernel, report this immediately to your vendor! **
[ 7.332880] ** **
[ 7.332885] ** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **
[ 7.332890] ********************************************************************
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| _| '_| / -_) ' \/ _` | | || \ \/\/ / '_| _|
|_||_| |_\___|_||_\__,_|_|\_, |\_/\_/|_| \__|
|__/
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FriendlyWrt 21.02.3, r16554-1d4dea6d4f
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root@FriendlyWrt:~#