Re: [LTP] [PATCH 5/8] Hugetlb: Migrating libhugetlbfs madvise_reserve

Richard Palethorpe
2022-12-12T14:23:45Z

Hello,

Looks good,

Reviewed-by: Richard Palethorpe <rpalethorpe@suse.com>

Tarun Sahu <tsahu@linux.ibm.com> writes:

> Migrating the libhugetlbfs/testcases/madvise_reserve.c test
>
> Test Description: madvise() 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 is fixed in kernel by 'commit f2deae9d4e70
> ("Remove implementation of readpage from the hugetlbfs_aops")'.
>
> Signed-off-by: Tarun Sahu <tsahu@linux.ibm.com>
> ---
> runtest/hugetlb | 1 +
> testcases/kernel/mem/.gitignore | 1 +
> .../kernel/mem/hugetlb/hugemmap/hugemmap16.c | 83 +++++++++++++++++++
> 3 files changed, 85 insertions(+)
> create mode 100644 testcases/kernel/mem/hugetlb/hugemmap/hugemmap16.c
>
> diff --git a/runtest/hugetlb b/runtest/hugetlb
> index 0714ed34c..1691ce37d 100644
> --- a/runtest/hugetlb
> +++ b/runtest/hugetlb
> @@ -17,6 +17,7 @@ hugemmap12 hugemmap12
> hugemmap13 hugemmap13
> hugemmap14 hugemmap14
> hugemmap15 hugemmap15
> +hugemmap16 hugemmap16
> hugemmap05_1 hugemmap05 -m
> hugemmap05_2 hugemmap05 -s
> hugemmap05_3 hugemmap05 -s -m
> diff --git a/testcases/kernel/mem/.gitignore b/testcases/kernel/mem/.gitignore
> index d59b60fd4..eb8e87c40 100644
> --- a/testcases/kernel/mem/.gitignore
> +++ b/testcases/kernel/mem/.gitignore
> @@ -16,6 +16,7 @@
> /hugetlb/hugemmap/hugemmap13
> /hugetlb/hugemmap/hugemmap14
> /hugetlb/hugemmap/hugemmap15
> +/hugetlb/hugemmap/hugemmap16
> /hugetlb/hugeshmat/hugeshmat01
> /hugetlb/hugeshmat/hugeshmat02
> /hugetlb/hugeshmat/hugeshmat03
> diff --git a/testcases/kernel/mem/hugetlb/hugemmap/hugemmap16.c b/testcases/kernel/mem/hugetlb/hugemmap/hugemmap16.c
> new file mode 100644
> index 000000000..ea940e90c
> --- /dev/null
> +++ b/testcases/kernel/mem/hugetlb/hugemmap/hugemmap16.c
> @@ -0,0 +1,83 @@
> +// SPDX-License-Identifier: LGPL-2.1-or-later
> +/*
> + * Copyright (C) 2005-2006 IBM Corporation.
> + * Author: Eric B Munson and Mel Gorman
> + */
> +
> +/*\
> + * [Description]
> + *
> + * madvise() 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 is fixed in kernel by commit f2deae9d4e70793568ef9e85d227abb7bef5b622
> + */
> +
> +#define _GNU_SOURCE
> +#include <stdio.h>
> +#include <sys/mount.h>
> +#include <limits.h>
> +#include <sys/param.h>
> +#include <sys/types.h>
> +
> +#include "hugetlb.h"
> +
> +#define MNTPOINT "hugetlbfs/"
> +static int fd = -1;
> +static long hpage_size;
> +
> +static void run_test(void)
> +{
> + void *p;
> + unsigned long initial_rsvd, map_rsvd, madvise_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);
> +
> + if (madvise(p, hpage_size, MADV_WILLNEED) == -1)
> + tst_brk(TBROK|TERRNO, "madvise()");
> + madvise_rsvd = SAFE_READ_MEMINFO(MEMINFO_HPAGE_RSVD);
> + tst_res(TINFO, "Reserve count after madvise: %lu", madvise_rsvd);
> +
> + 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("Hugepagesize:")*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,
> + .needs_tmpdir = 1,
> + .setup = setup,
> + .cleanup = cleanup,
> + .test_all = run_test,
> + .hugepages = {1, TST_NEEDS},
> +};
> --
> 2.31.1

--
Thank you,
Richard.