1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2024 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. 4 */ 5 6 #include <assert.h> 7 #include <stdbool.h> 8 #include <stdint.h> 9 #include <stdio.h> 10 #include <stdlib.h> 11 #include <unistd.h> 12 #include <signal.h> 13 #include <sys/mman.h> 14 #include <linux/mman.h> 15 16 #include "../kselftest.h" 17 18 int main(int argc, char *argv[]) 19 { 20 size_t alloc_size = 134217728; 21 size_t page_size = getpagesize(); 22 void *alloc; 23 pid_t child; 24 25 ksft_print_header(); 26 ksft_set_plan(1); 27 28 alloc = mmap(0, alloc_size, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_DROPPABLE, -1, 0); 29 assert(alloc != MAP_FAILED); 30 memset(alloc, 'A', alloc_size); 31 for (size_t i = 0; i < alloc_size; i += page_size) 32 assert(*(uint8_t *)(alloc + i)); 33 34 child = fork(); 35 assert(child >= 0); 36 if (!child) { 37 for (;;) 38 *(char *)malloc(page_size) = 'B'; 39 } 40 41 for (bool done = false; !done;) { 42 for (size_t i = 0; i < alloc_size; i += page_size) { 43 if (!*(uint8_t *)(alloc + i)) { 44 done = true; 45 break; 46 } 47 } 48 } 49 kill(child, SIGTERM); 50 51 ksft_test_result_pass("MAP_DROPPABLE: PASS\n"); 52 exit(KSFT_PASS); 53 } 54