sort segmentation fault

main.cpp

#include <iostream>
#include <vector>
#include <algorithm>

// gcc version 11.2.0 (Ubuntu 11.2.0-19ubuntu1)

int main()
{
  const std::vector<int> v = { 1, 4, 2, 5, 5, 2, 3, 5, 2, 3, 4, 6, 3, 2, 5, 1, 2, 3, 4, 5, 6, 5, 6 };
  std::vector<const int*> vp(v.size());
  for (int i = 0; i < v.size(); ++i) vp[i] = &v[i];

  std::sort(vp.begin(), vp.end(), [](const int* a, const int* b) {
    // Segmentation fault (core dumped)
    return *a <= *b;

    // 1, 1, 2, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 5, 5, 5, 5, 5, 5, 6, 6, 6,
    //return *a < *b;
    });

  std::for_each(vp.begin(), vp.end(), [](const int* x) { std::cout << *x << ", "; });
  std::cout << std::endl;
}