Segmentation fault if I try to print all the argv arguments with a loop

.global main
.type main%function

@ r4 = argc
@ r5 = current offset
@ r6 = end offset
@ r7 = array argv

main:
    mov r4,r0
    ldr r0,=message
    mov r5,#0       // initialize offset
    mov r6,#4
    mul r6,r4,r6    // calculate end offset
    mov r7,r1       // put array argv in r7
loop:
    ldr r1,[r7,r5]  // load the argv element with offset r5
    push {ip,lr}    // save lr
    bl printf
    pop {ip,lr}
    add r5,r5,#4    // go to next word
    cmp r5,r6
    bne loop        // if I haven't reached the end offset, it does another cycle
end:
    mov r0,#0       // clear exit code
    bx lr           // returns
    
message:
    .asciz "%s\n"

Output:

$ ./a.out a
./a.out
Segmentation fault

but:

$ ./a.out      
./a.out

so apparently the problems comes when I try to access the next element of the array... really don't know why... I'm new with arm and assembly..