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1// SPDX-License-Identifier: GPL-2.02/*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 18int 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