[LTP] [PATCH v6 2/2] Hugetlb: Migrating libhugetlbfs fadvise_reserve

[Tarun Sahu <tsahu@linux.ibm.com>]

Migrating the libhugetlbfs/testcases/fadvise_reserve.c test

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  | 84 +++++++++++++++++++
 3 files changed, 86 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..ae132107c
--- /dev/null
+++ b/testcases/kernel/mem/hugetlb/hugemmap/hugemmap12.c
@@ -0,0 +1,84 @@
+// 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 <stdio.h>
+#include <sys/mount.h>
+#include <limits.h>
+#include <sys/param.h>
+#include <sys/types.h>
+
+#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},
+};
-- 
2.31.1


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