[LTP] [PATCH v2 5/8] Hugetlb: Migrating libhugetlbfs madvise_reserve

[Tarun Sahu]

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>
Reviewed-by: Richard Palethorpe <rpalethorpe@suse.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..2003e7013
--- /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 f2deae9d4e70
+ */
+
+#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