[LTP] [PATCH] Migrating the libhugetlbfs/testcases/truncate_sigbus_versus_oom.c test

[Samir Mulani]

In this test case, we are verifying the bug fix commit that is attached as
a part of the test case structure,

Some kernel have a bug in the positioning of the test against
i_size.  This bug means that attempting to instantiate a page
beyond the end of a hugepage file can result in an OOM and SIGKILL
instead of the correct SIGBUS.

Signed-off-by: Samir Mulani <samir@linux.vnet.ibm.com>
---
 .../kernel/mem/hugetlb/hugemmap/hugemmap37.c  | 90 +++++++++++++++++++
 1 file changed, 90 insertions(+)
 create mode 100644 testcases/kernel/mem/hugetlb/hugemmap/hugemmap37.c

diff --git a/testcases/kernel/mem/hugetlb/hugemmap/hugemmap37.c b/testcases/kernel/mem/hugetlb/hugemmap/hugemmap37.c
new file mode 100644
index 000000000..8bd5327b8
--- /dev/null
+++ b/testcases/kernel/mem/hugetlb/hugemmap/hugemmap37.c
@@ -0,0 +1,90 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2005-2006 David Gibson & Adam Litke, IBM Corporation.
+ */
+
+/*\
+ * [Description]
+ *
+ * Test Name: Truncate_sigbus_versus_oom
+ *
+ * Some kernel have a bug in the positioning of the test against
+ * i_size.  This bug means that attempting to instantiate a page
+ * beyond the end of a hugepage file can result in an OOM and SIGKILL
+ * instead of the correct SIGBUS.
+ */
+
+#include "hugetlb.h"
+
+#define MNTPOINT "hugetlbfs/"
+#define PTS_PASS 0
+static int  fd = -1, fdx = -1;
+
+static unsigned long long hpage_size;
+static unsigned long totpages;
+
+static void sigbus_handler(int signum)
+{
+	if (signum == SIGBUS) {
+		tst_res(TPASS, "Test PASSED\n");
+		_exit(PTS_PASS);
+	}
+}
+
+struct sigaction sa = {
+	.sa_sigaction = sigbus_handler,
+	.sa_flags = SA_SIGINFO,
+};
+
+static void run_test(void)
+{
+	void *p, *q;
+	int i;
+
+	fd = tst_creat_unlinked(MNTPOINT, 0);
+	p = SAFE_MMAP(NULL, hpage_size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
+	SAFE_FTRUNCATE(fd, 0);
+
+	fdx = tst_creat_unlinked(MNTPOINT, 0);
+	q = SAFE_MMAP(NULL, totpages * hpage_size, PROT_READ|PROT_WRITE, MAP_SHARED, fdx, 0);
+	/* Touch the pages to ensure they're removed from the pool */
+	for (i = 0; i < totpages; i++) {
+		volatile char *x = (volatile char *)q + i*hpage_size;
+		*x = 0;
+	}
+	/* SIGBUS is what *should* happen */
+	SAFE_FTRUNCATE(fdx, 0);
+	*((volatile unsigned int *)p);
+	tst_res(TPASS, "Didn't SIGBUS or OOM");
+}
+
+void setup(void)
+{
+	SAFE_SIGACTION(SIGBUS, &sa, NULL);
+	totpages = SAFE_READ_MEMINFO(MEMINFO_HPAGE_FREE);
+	hpage_size = tst_get_hugepage_size();
+}
+
+void cleanup(void)
+{
+	if (fd > 0)
+		SAFE_CLOSE(fd);
+	if (fdx > 0)
+		SAFE_CLOSE(fdx);
+}
+
+
+static struct tst_test test = {
+	.tags = (struct tst_tag[]) {
+		{"linux-git", "0d59a01bc461"},
+		{}
+	},
+	.needs_root = 1,
+	.mntpoint = MNTPOINT,
+	.needs_hugetlbfs = 1,
+	.needs_tmpdir = 1,
+	.setup = setup,
+	.cleanup = cleanup,
+	.test_all = run_test,
+	.hugepages = {2, TST_NEEDS},
+};
-- 
2.39.3