centos 8 x64 run time error

[tmprecorder]

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x8 pc=0x6bdfe5]

goroutine 1 [running]:
github.com/bufsnake/blueming/internal/core.(*core).backup(0xc000274000)
/home/runner/work/blueming/blueming/internal/core/core.go:136 +0x3c5
github.com/bufsnake/blueming/internal/core.(*core).Core(0x64)
/home/runner/work/blueming/blueming/internal/core/core.go:67 +0x2c
main.main()
/home/runner/work/blueming/blueming/cmd/blueming/main.go:206 +0x1bb6