Build failed error when compiling

I was trying to compile bu I got this error.
i try : make , make -j5 , make toolchain/install , ....

make[1] world
make[2] tools/compile
make[2] package/cleanup
make[3] -C tools/flock compile
make[3] -C tools/xz compile
make[3] -C tools/sed compile
make[3] -C tools/patch compile
make[3] -C tools/tar compile
ERROR: tools/tar failed to build.
make -r world: build failed. Please re-run make with -j1 V=s or V=sc for a higher verbosity level to see what's going on

make -j1 V=s

Pure guess for the reason: you are trying to do the build as root.
OpenWrt needs to be built by a non-root account at the buildhost.