The program returns error "attempt to execute non-instruction at 0x00000000"

I have been given HW regarding RISC-V. The tasks is to solve the recurring equation T(n) = 2T(n/2)+n if the n or input is >=2, otherwise it returns 1. I have tried to create the solution code but it keeps giving me the (error) attempt to execute non-instruction at 0x00000000. Can someone please tell me where is my mistake and how to fix it? Thank you for your time!

Notes: I can only starts to write the code from the "Write your recursive code here...."

.globl __start

.rodata
    msg_input: .string "Enter a number: "
    msg_result: .string "The result is: "
    newline: .string "\n"

.text

__start:
  # prints msg_input
    li a0, 4
    la a1, msg_input
    ecall
  # read from standard input
    li a0, 5
    ecall

################################################################################ 
# write your recursive code here, input is in a0, store the result(integer type) to t0
    jal findsum 
findsum:
    li t0, 2            #t0==2
    blt a0, t0, L1      #if n<2 return 1
    addi sp, sp, -8     #reserve stack area
    sw ra, 0(sp)        #save return address
    sw a0, 4(sp)        #save input 
    li t0, 2            #t0==2
    div a0, a0, t0      #n=n/2
    jal findsum         #call findsum(n/2)
                        #a1=FindSum(n/2)
    li t0, 2            #t0=2
    mul a1, t0, a1      #a1=2*FindSum(n/2)
    addi a1, a1, 2      #a1=2*FindSum(n/2)+2
    j done

L1:
    li a1, 1    

done:
    lw ra, 0(sp)
    addi sp, sp, 8
    jr ra

################################################################################

result:
  # prints msg_result
    li a0, 4
    la a1, msg_result
    ecall
  # prints the result in t0
    li a0, 1
    mv a1, t0
    ecall
  # ends the program with status code 0
    li a0, 10
    ecall