[LTP] [PATCH 6/8] Hugetlb: Migrating libhugetlbfs map_high_truncate_2

[Tarun Sahu]

Migrating the libhugetlbfs/testcases/map_high_truncate_2.c test

Test Description: At one stage, a misconversion of hugetlb_vmtruncate_list
to a prio_tree meant that on 32-bit machines, certain combinations of
mapping and truncations could truncate incorrect pages, or
overwrite pmds from other VMAs, triggering BUG_ON()s or other
wierdness.

Test adapted from an example by Kenneth Chen <kenneth.w.chen@intel.com>

WARNING: The offsets and addresses used within are specifically
calculated to trigger the bug as it existed.  Don't mess with them
unless you *really* know what you're doing.

The kernel bug in question was fixed with
'commit 856fc2950555 ("[PATCH] hugetlb: fix prio_tree unit")'.

Signed-off-by: Tarun Sahu <tsahu@linux.ibm.com>
---
 runtest/hugetlb                               |   1 +
 testcases/kernel/mem/.gitignore               |   1 +
 .../kernel/mem/hugetlb/hugemmap/hugemmap17.c  | 103 ++++++++++++++++++
 3 files changed, 105 insertions(+)
 create mode 100644 testcases/kernel/mem/hugetlb/hugemmap/hugemmap17.c

diff --git a/runtest/hugetlb b/runtest/hugetlb
index 1691ce37d..5fac3481c 100644
--- a/runtest/hugetlb
+++ b/runtest/hugetlb
@@ -18,6 +18,7 @@ hugemmap13 hugemmap13
 hugemmap14 hugemmap14
 hugemmap15 hugemmap15
 hugemmap16 hugemmap16
+hugemmap17 hugemmap17
 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 eb8e87c40..6aa54f902 100644
--- a/testcases/kernel/mem/.gitignore
+++ b/testcases/kernel/mem/.gitignore
@@ -17,6 +17,7 @@
 /hugetlb/hugemmap/hugemmap14
 /hugetlb/hugemmap/hugemmap15
 /hugetlb/hugemmap/hugemmap16
+/hugetlb/hugemmap/hugemmap17
 /hugetlb/hugeshmat/hugeshmat01
 /hugetlb/hugeshmat/hugeshmat02
 /hugetlb/hugeshmat/hugeshmat03
diff --git a/testcases/kernel/mem/hugetlb/hugemmap/hugemmap17.c b/testcases/kernel/mem/hugetlb/hugemmap/hugemmap17.c
new file mode 100644
index 000000000..1815765d2
--- /dev/null
+++ b/testcases/kernel/mem/hugetlb/hugemmap/hugemmap17.c
@@ -0,0 +1,103 @@
+// SPDX-License-Identifier: LGPL-2.1-or-later
+/*
+ * Copyright (C) 2005-2006 David Gibson & Adam Litke, IBM Corporation.
+ * Author: David Gibson & Adam Litke
+ */
+
+/*\
+ * [Descriptiom]
+ *
+ * At one stage, a misconversion of hugetlb_vmtruncate_list to a prio_tree
+ * meant that on 32-bit machines, certain combinations of mapping and
+ * truncations could truncate incorrect pages, or overwrite pmds from
+ * other VMAs, triggering BUG_ON()s or other wierdness.
+ *
+ * Test adapted from an example by Kenneth Chen <kenneth.w.chen@intel.com>
+ *
+ * WARNING: The offsets and addresses used within are specifically
+ * calculated to trigger the bug as it existed.  Don't mess with them
+ * unless you *really* know what you're doing.
+ *
+ * The kernel bug in question was fixed with commit
+ * 856fc29505556cf263f3dcda2533cf3766c14ab6.
+ */
+
+#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/"
+#define MAP_LENGTH	(4UL * hpage_size)
+#if defined(__s390__) && __WORDSIZE == 32
+#define TRUNCATE_POINT 0x20000000UL
+#else
+#define TRUNCATE_POINT 0x60000000UL
+#endif
+#define HIGH_ADDR	0xa0000000UL
+#define FOURGIG		((off64_t)0x100000000ULL)
+
+static unsigned long hpage_size;
+static int  fd = -1;
+
+static void run_test(void)
+{
+	char *p, *q;
+	unsigned long i;
+
+	p = SAFE_MMAP(0, MAP_LENGTH + TRUNCATE_POINT, PROT_READ | PROT_WRITE,
+		 MAP_PRIVATE | MAP_NORESERVE, fd, 0);
+
+	SAFE_MUNMAP(p, MAP_LENGTH + TRUNCATE_POINT);
+
+	q = SAFE_MMAP((void *)HIGH_ADDR, MAP_LENGTH, PROT_READ | PROT_WRITE,
+		 MAP_PRIVATE, fd, 0);
+	tst_res(TINFO, "High map at %p", q);
+
+	for (i = 0; i < MAP_LENGTH; i += hpage_size)
+		q[i] = 1;
+
+	SAFE_FTRUNCATE(fd, TRUNCATE_POINT);
+
+	if (q[0] != 1)
+		tst_res(TFAIL, "data mismatch");
+	else
+		tst_res(TPASS, "Successful");
+
+	SAFE_MUNMAP(q, MAP_LENGTH);
+}
+
+static void setup(void)
+{
+	hpage_size = SAFE_READ_MEMINFO("Hugepagesize:")*1024;
+
+	if (hpage_size > TRUNCATE_POINT)
+		tst_brk(TCONF, "Huge page size is too large");
+	if (TRUNCATE_POINT % hpage_size)
+		tst_brk(TCONF, "Truncation point is not aligned to huge page size");
+	fd = tst_creat_unlinked(MNTPOINT, 0);
+}
+
+static void cleanup(void)
+{
+	if (fd >= 0)
+		SAFE_CLOSE(fd);
+}
+
+static struct tst_test test = {
+	.tags = (struct tst_tag[]) {
+		{"linux-git", "856fc2950555"},
+		{}
+	},
+	.needs_root = 1,
+	.mntpoint = MNTPOINT,
+	.needs_hugetlbfs = 1,
+	.setup = setup,
+	.cleanup = cleanup,
+	.test_all = run_test,
+	.hugepages = {4, TST_NEEDS},
+};
-- 
2.31.1