[LTP] [PATCH 06/29] Hugetlb: Migrating libhugetlbfs fadvise_reserve

[Cyril Hrubis]

Hi!
> Test 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
> 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/hugemmap12.c  | 114 ++++++++++++++++++
>  3 files changed, 116 insertions(+)
>  create mode 100644 testcases/kernel/mem/hugetlb/hugemmap/hugemmap12.c
> 
> diff --git a/runtest/hugetlb b/runtest/hugetlb
> index b9ee7227d..b019c4195 100644
> --- a/runtest/hugetlb
> +++ b/runtest/hugetlb
> @@ -8,6 +8,7 @@ hugemmap08 hugemmap08
>  hugemmap09 hugemmap09
>  hugemmap10 hugemmap10
>  hugemmap11 hugemmap11
> +hugemmap12 hugemmap12
>  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 3e64b67be..ec250592d 100644
> --- a/testcases/kernel/mem/.gitignore
> +++ b/testcases/kernel/mem/.gitignore
> @@ -9,6 +9,7 @@
>  /hugetlb/hugemmap/hugemmap09
>  /hugetlb/hugemmap/hugemmap10
>  /hugetlb/hugemmap/hugemmap11
> +/hugetlb/hugemmap/hugemmap12
>  /hugetlb/hugeshmat/hugeshmat01
>  /hugetlb/hugeshmat/hugeshmat02
>  /hugetlb/hugeshmat/hugeshmat03
> diff --git a/testcases/kernel/mem/hugetlb/hugemmap/hugemmap12.c b/testcases/kernel/mem/hugetlb/hugemmap/hugemmap12.c
> new file mode 100644
> index 000000000..9773199ca
> --- /dev/null
> +++ b/testcases/kernel/mem/hugetlb/hugemmap/hugemmap12.c
> @@ -0,0 +1,114 @@
> +// SPDX-License-Identifier: LGPL-2.1-or-later
> +/*
> + * Copyright (C) 2005-2006 IBM Corporation.
> + *
> + * Test Name: fadvise_reserve
> + *
> + * Test 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

Here as well.

> + * f2deae9d4e70793568ef9e85d227abb7bef5b622.

This hash should be added into .tags in the tst_test structure instead.

> + * HISTORY
> + *  Written by Mel Gorman
> + */
> +
> +#define _GNU_SOURCE
> +#include <stdio.h>
> +#include <sys/mount.h>
> +#include <limits.h>
> +#include <sys/param.h>
> +#include <sys/types.h>
> +
> +#include "hugetlb.h"
> +
> +static long hpage_size;
> +static int  fd = -1;
> +static char hfile[MAXPATHLEN];
> +static char *verbose;
> +
> +static void run_test(void)
> +{
> +	void *p;
> +	unsigned long initial_rsvd, map_rsvd, fadvise_rsvd, end_rsvd;
> +
> +	fd = SAFE_OPEN(hfile, O_RDWR | O_CREAT, 0600);
> +	SAFE_UNLINK(hfile);
> +
> +	initial_rsvd = SAFE_READ_MEMINFO("HugePages_Rsvd:");
> +	if (verbose)
> +		tst_res(TINFO, "Reserve count before map: %lu", initial_rsvd);

Here as well, not keen on the verbose flag.

> +	/* mmap a region and record reservations */

Here as well, no useless comments.

> +	p = SAFE_MMAP(NULL, hpage_size, PROT_READ|PROT_WRITE, MAP_SHARED,
> +		 fd, 0);
> +	map_rsvd = SAFE_READ_MEMINFO("HugePages_Rsvd:");
> +	if (verbose)
> +		tst_res(TINFO, "Reserve count after map: %lu", map_rsvd);
> +
> +	/* fadvise the region and record reservations */
> +	if (posix_fadvise(fd, 0, hpage_size, POSIX_FADV_WILLNEED) == -1) {
> +		tst_res(TFAIL|TERRNO, "fadvise()");
> +		goto fail;
> +	}
> +	fadvise_rsvd = SAFE_READ_MEMINFO("HugePages_Rsvd:");
> +	if (verbose)
> +		tst_res(TINFO, "Reserve count after fadvise: %lu", fadvise_rsvd);
> +
> +	/* Write the region */

Here as well.

> +	memset(p, 1, hpage_size);
> +
> +	/* Free region */

And here as well.

> +	SAFE_MUNMAP(p, hpage_size);
> +	SAFE_CLOSE(fd);
> +	end_rsvd = SAFE_READ_MEMINFO("HugePages_Rsvd:");
> +	if (verbose)
> +		tst_res(TINFO, "Reserve count after close: %lu", end_rsvd);
> +
> +	/* Reserve count should match initial reserve count */

And here.

> +	if (end_rsvd != initial_rsvd) {
> +		tst_res(TFAIL, "Reserve leaked: %lu != %lu", end_rsvd, initial_rsvd);
> +		goto fail;
> +	}
> +	tst_res(TPASS, "Successful");

Just TST_EXP_EQ_LU(end_rsvd, initial_rsvd);

> +	return;
> +fail:
> +	tst_brk(TBROK, "Once failed, No point in continuing the test");

Here as well, no tst_brk() like this.

> +}
> +
> +static void setup(void)
> +{
> +	if (tst_hugepages < 1)
> +		tst_brk(TCONF, "Not enough hugepages for testing.");
> +
> +	if (!Hopt)
> +		Hopt = tst_get_tmpdir();
> +	SAFE_MOUNT("none", Hopt, "hugetlbfs", 0, NULL);
> +
> +	snprintf(hfile, sizeof(hfile), "%s/ltp_hugetlbfile%d", Hopt, getpid());
> +	hpage_size = SAFE_READ_MEMINFO("Hugepagesize:")*1024;
> +}
> +
> +static void cleanup(void)
> +{
> +	if (fd >= 0)
> +		SAFE_CLOSE(fd);
> +	umount2(Hopt, MNT_DETACH);

Here as well.

> +}
> +
> +static struct tst_test test = {
> +	.needs_root = 1,
> +	.needs_tmpdir = 1,
> +	.options = (struct tst_option[]) {
> +		{"v", &verbose, "Turns on verbose mode"},
> +		{"H:", &Hopt,   "Location of hugetlbfs, i.e.  -H /var/hugetlbfs"},
> +		{"s:", &nr_opt, "Set the number of the been allocated hugepages"},
> +		{}
> +	},
> +	.setup = setup,
> +	.cleanup = cleanup,
> +	.test_all = run_test,
> +	.hugepages = {1, TST_REQUEST},
> +};
> -- 
> 2.31.1
> 
> 
> -- 
> Mailing list info: https://lists.linux.it/listinfo/ltp

-- 
Cyril Hrubis
chrubis@suse.cz