SIGSEGV russian roulette

russian_roulette.c

#include <sys/random.h>
int main() {
    void(*j)(void);
    int r;
    getrandom(&r, 1, GRND_RANDOM);
    if ( (r%10) == 0)
        j(); //j points to nowhere == SIGSEGV

    return(0);
}

russian_roulette.S

.section .text
.global _start
_start:
    pushq %rbp
    movq %rsp, %rbp
    subq $1, %rbp

// call sys_getrandom
    movl $318, %eax
    leaq -1(%rbp), %rdi
    movb $1, %sil
    movb $0x2, %dl
    syscall

// get n < 10
    movl (%rdi), %eax
    shr $1, %eax
    movb $10, %bl
    div %bl

    shr $8, %eax
// if %al != 0 then SIGSEGV
    cmpb $0, %al
    jne .safe
    retq

.safe:
    popq %rbp
    xorq %rax, %rax
    xorq %rdi, %rdi
    movb $60, %al
    syscall