// SPDX-License-Identifier: LGPL-2.1-or-later /* * Copyright (C) 2005-2006 IBM Corporation. * Author: Mel Gorman */ /*\ * [Description] * * fadvise() on some kernels can cause the reservation counter to get * corrupted. The problem is that the patches are allocated for the * reservation but not faulted in at the time of allocation. The counters * do not get updated and effectively "leak". This test identifies whether * the kernel is vulnerable to the problem or not. It's fixed in kernel * by commit f2deae9d4e70793568ef9e85d227abb7bef5b622. */ #define _GNU_SOURCE #include #include #include #include #include #include "hugetlb.h" #define MNTPOINT "hugetlbfs/" static long hpage_size; static int fd = -1; static void run_test(void) { void *p; unsigned long initial_rsvd, map_rsvd, fadvise_rsvd, end_rsvd; fd = tst_creat_unlinked(MNTPOINT, 0); initial_rsvd = SAFE_READ_MEMINFO(MEMINFO_HPAGE_RSVD); tst_res(TINFO, "Reserve count before map: %lu", initial_rsvd); p = SAFE_MMAP(NULL, hpage_size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0); map_rsvd = SAFE_READ_MEMINFO(MEMINFO_HPAGE_RSVD); tst_res(TINFO, "Reserve count after map: %lu", map_rsvd); SAFE_POSIX_FADVISE(fd, 0, hpage_size, POSIX_FADV_WILLNEED); fadvise_rsvd = SAFE_READ_MEMINFO(MEMINFO_HPAGE_RSVD); tst_res(TINFO, "Reserve count after fadvise: %lu", fadvise_rsvd); memset(p, 1, hpage_size); SAFE_MUNMAP(p, hpage_size); SAFE_CLOSE(fd); end_rsvd = SAFE_READ_MEMINFO(MEMINFO_HPAGE_RSVD); tst_res(TINFO, "Reserve count after close: %lu", end_rsvd); TST_EXP_EQ_LU(end_rsvd, initial_rsvd); } static void setup(void) { hpage_size = SAFE_READ_MEMINFO(MEMINFO_HPAGE_SIZE)*1024; } static void cleanup(void) { if (fd > 0) SAFE_CLOSE(fd); } static struct tst_test test = { .tags = (struct tst_tag[]) { {"linux-git", "f2deae9d4e70"}, {} }, .needs_root = 1, .mntpoint = MNTPOINT, .needs_hugetlbfs = 1, .setup = setup, .cleanup = cleanup, .test_all = run_test, .hugepages = {1, TST_NEEDS}, };