C++: SIGBUS Error after increasing stack size to avoid SIGSEV

Question

UPDATE: I solved it, just increased the stack size to 0x40000000, and now my code runs perfectly. (Earlier, I thought the stack size would be sufficient because I was getting a different error before (SIGSEV), and I did not think SIGBUS was also due to stack size)

I am a beginner in C++ and I have to run my recursive code on some very large inputs.

After running, I got SIGSEV Error, and I figured out that it's probably due to low stack size.

I am using CLion and I added

set(CMAKE_EXE_LINKER_FLAGS "-Wl,-stack_size,0x20000000")

to CMakeLists.txt

Now, when I run my code, I get SIGBUS Error (interrupted by signal 10: SIGBUS).

Does anyone know why this could happen and how to fix this?

My Code:

void dfs(int x, int y) {
    if (vis[x][y]) {
        return;
    }
    vis[x][y] = 1;

    if (!useless[x][y]) {
        int cnt_ok = 0;
        for (int d = 0; d < 4; ++d) {
            int nx = x + dx[d];
            int ny = y + dy[d];

            if (valid(nx, ny)) {
                cnt_ok += !useless[nx][ny];
            }
        }
        useless[x][y] = cnt_ok < 2;
    }

    for (int d = 0; d < 4; ++d) {
        int nx = x + dx[d];
        int ny = y + dy[d];

        if (valid(nx, ny)) {
            dfs(nx, ny);
        }
    }
}

This is a DFS on 2-D Grid and function valid() checks for whether the coordinates are valid or not.

dx[4] = {-1, 1, 0, 0} dy[4] = {0, 0, 1, -1}

The dimensions of vis and useless vectors are just the dimensions of the grid.

When I run with debugger in CLion:

(Line 62 is where the void dfs(int x, int y) is written. Line 86 is where dfs(nx, ny) is written.)

Also, if it's relevant - the file is so large that my computer becomes very slow and laggy when my code is running.

I also ran this code on smaller inputs and the code works perfectly fine.

Surprisingly, if a comment out the if (!useless[x][y]) the code runs fine even on large inputs and exits normally.

(Please focus on the code itself, I am beginner in c++, and I just implement pseudo-code given in books, so my code may not align with best practices.)

Thanks!