Why there is a segmentaion fault in a simple32 bit linux assembly program?

First of all I want to start off by saying that I've read this, this and this question. Yet none of the answers provided on these questions were sufficient/had detailed enough information in order to answer my question. Moreover, they are all 4 - 6 years old which makes them outdated. With that being said, I opened a new question here.

I am trying to make a simple program that displays 1 - 4 matrices in Linux 32-bit assembly with NASM syntax, I've made a procedure that should print the simple 1x1 matrix.

section .data
    msg1:       db 'output:', 10
    msg1len:    equ $-msg1

    endmsg:     db 10

    m1r1:       db '5'

    m2r1:       db '1', '4'
    m2r2:       db '2', '6'

    m3r1:       db '8', '3', '4'
    m3r2:       db '9', '2', '1'
    m3r3:       db '1', '5', '6'

    m4r1:       db '6', '3', '1', '7'
    m4r2:       db '1', '9', '8', '4'
    m4r3:       db '5', '0', '1', '2'
    m4r4:       db '2', '7', '1', '0'

section .bss
    output1:    resb 5
    output2:    resb 7*2
    output3:    resb 9*3
    output4:    resb 11*4


section .text
    global  _start

_start:
    mov eax, 1
    call printMatrix


_exit:
    mov eax, 0
    mov ebx, 1
    int 80h

;description:
;   displays a visual representation of
;   a matrix from size 1 through 4
;parameters:
;   eax - matrix size
printMatrix:
    push eax
    push ebx
    push ecx
    push edx
    push esi

    cmp eax, 1
    je .printMatrix1

    cmp eax, 2
    je .printMatrix2

    cmp eax, 3
    je .printMatrix3

    cmp eax, 4
    je .printMatrix4

.printMatrix1:
    mov eax, '[ '
    mov [output1], eax
    mov eax, m1r1
    mov [output1 + 2], eax
    mov eax, ' '
    mov [output1 + 3], eax
    mov eax, ']'
    mov [output1 + 4], eax

    mov eax, 4
    mov ebx, 1
    mov ecx, [output1]
    mov edx, 5
    jmp .exit

.printMatrix2:

    jmp .exit

.printMatrix3:

    jmp .exit

.printMatrix4:

    jmp .exit

.exit:
    pop esi
    pop edx
    pop ecx
    pop ebx
    pop eax
    ret

printEndl:
    push eax
    push ebx
    push ecx
    push edx
    mov eax, 4
    mov ebx, 1
    mov ecx, endmsg
    mov edx, 1
    int 80h
    pop edx
    pop ecx
    pop ebx
    pop eax
    ret

Yet when I compile via:

nasm -f elf32 matrix.asm

And link using:

ld -m elf_i386 -s -o matrix matrix.o

I get no errors/warnings whatsoever, but when I run the program using ./matrix I get segmentation fault (core dumped) error. Now I must note that this question provided a rather well definition for what is a segmentation fault and what it's usually caused by, it was a bit unclear though. What I seek is:

1. A proper explanation/definition of a segmentation in terms of memory and assembly.
2. What have caused the fault in this particular case (According to the first and second links, I suspect it has something to do with the jumps or calling procedures and the stack. However I've been sitting here for hours trying to figure out what caused it with no success).
3. How to avoid such a fault and recommended future practices.