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// SPDX-License-Identifier: GPL-2.0 /* * Copyright (C) 2024 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. */ #include <assert.h> #include <stdbool.h> #include <stdint.h> #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <signal.h> #include <sys/mman.h> #include <linux/mman.h> #include "../kselftest.h" int main(int argc, char *argv[]) { size_t alloc_size = 134217728; size_t page_size = getpagesize(); void *alloc; pid_t child; ksft_print_header(); ksft_set_plan(1); alloc = mmap(0, alloc_size, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_DROPPABLE, -1, 0); assert(alloc != MAP_FAILED); memset(alloc, 'A', alloc_size); for (size_t i = 0; i < alloc_size; i += page_size) assert(*(uint8_t *)(alloc + i)); child = fork(); assert(child >= 0); if (!child) { for (;;) *(char *)malloc(page_size) = 'B'; } for (bool done = false; !done;) { for (size_t i = 0; i < alloc_size; i += page_size) { if (!*(uint8_t *)(alloc + i)) { done = true; break; } } } kill(child, SIGTERM); ksft_test_result_pass("MAP_DROPPABLE: PASS\n"); exit(KSFT_PASS); }