问从程序集调用C函数调用printf时的分割故障

EN

void quicksort(int* arr, size_t n) {
    if (n <= 1) return;
    int p = partition(arr, n);
    quicksort(arr, p);
    p += 1;
    quicksort(arr+p, n-p);
}

# quicksort.s

# Takes an array of integers in %rsi
# Takes the size of the array in %rsi
.global quicksort
quicksort:
    cmpq $1, %rsi
    jle early_exit

    pushq %rbp
    movq %rsp, %rbp

    # rbx, r12 and r13 are callee-saved
    pushq %rbx
    pushq %r12
    pushq %r13

    # put arguments in callee-saved registers for later use
    movq %rdi, %rbx
    movq %rsi, %r12

    # p = partition(arr, n)
    call partition

    # put result of partition in callee-saved register for later use
    movq %rax, %r13

    # quicksort(arr, p)
    movq %rbx, %rdi
    movq %r13, %rsi
    call quicksort

    # p += 1
    addq $1, %r13

    # quicksort(arr+p*sizeof(int), n-p)
    leaq (%rbx, %r13, 4), %rdi
    movq %r12, %rsi
    subq %r13, %rsi
    call quicksort

    popq %r13
    popq %r12
    popq %rbx

    movq %rbp, %rsp
    popq %rbp

early_exit:
    ret

// quicksort.c
#include <stdio.h>
#include <stddef.h>
#include <stdlib.h>

void quicksort(int* arr, size_t n);

size_t partition(int* arr, size_t n) {
    // commenting the next line fixes the segfault
    fprintf(stderr, "%d", 10);

    size_t l = 1;
    size_t r = n;
    int p = arr[0];

    while (l < r) {
        while (l < r && arr[l] <= p) l++;
        while (l < r && arr[r-1] > p) r--;
        if (l == r) break;
        int temp = arr[l];
        arr[l] = arr[r-1];
        arr[r-1] = temp;
        l++;
        r--;
    }
    arr[0] = arr[r-1];
    arr[r-1] = p;
    return r-1;
}

int main() {
    #define LEN 100
    int arr[LEN] = { };

    for (int i = 0; i < LEN; ++i)
        arr[i] = rand();

    quicksort(arr, LEN);

    for (int i = 0; i < LEN; ++i)
        printf(" %d", arr[i]);
    putchar('\n');
}