Comment 1 for bug 1571725

I think this show the problem: path=0x0:
#9 0x00005574949bcb15 in recursive_delete (path=0x0) at ../source4/smbd/server.c:56
        dir = <optimized out>
        de = <optimized out>
        __FUNCTION__ = "recursive_delete"
#10 0x00005574949bd416 in cleanup_tmp_files (lp_ctx=<optimized out>) at ../source4/smbd/server.c:102
        path = <optimized out>
        mem_ctx = 0x557495b2dad0

cleanup_tmp_files():
static void cleanup_tmp_files(struct loadparm_context *lp_ctx)
{
    char *path;
    TALLOC_CTX *mem_ctx = talloc_new(NULL);

    path = smbd_tmp_path(mem_ctx, lp_ctx, NULL);

    recursive_delete(path);
    talloc_free(mem_ctx);
}

So path got a NULL value somehow, according to the stacktrace.