[LTP] [PATCH 07/13] Hugetlb: Migrating libhugetlbfs noresv-reserve-resv-page

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

Migrating the libhugetlbfs/testcases/noresv-preserve-resv-page.c test

Test Description: Test to preserve a reserved page against no-reserved
mapping. If all hugepages are reserved, access to no-reserved shared
mapping cause a process die, instead of stealing a hugepage which is
reserved for other process.

Signed-off-by: Tarun Sahu <tsahu@linux.ibm.com>
---
 runtest/hugetlb                               |   1 +
 testcases/kernel/mem/.gitignore               |   1 +
 .../kernel/mem/hugetlb/hugemmap/hugemmap27.c  | 136 ++++++++++++++++++
 3 files changed, 138 insertions(+)
 create mode 100644 testcases/kernel/mem/hugetlb/hugemmap/hugemmap27.c

diff --git a/runtest/hugetlb b/runtest/hugetlb
index 55185f2f7..d108542d2 100644
--- a/runtest/hugetlb
+++ b/runtest/hugetlb
@@ -27,6 +27,7 @@ hugemmap22 hugemmap22
 hugemmap23 hugemmap23
 hugemmap25 hugemmap25
 hugemmap26 hugemmap26
+hugemmap27 hugemmap27
 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 4886c6a5f..9862414c6 100644
--- a/testcases/kernel/mem/.gitignore
+++ b/testcases/kernel/mem/.gitignore
@@ -26,6 +26,7 @@
 /hugetlb/hugemmap/hugemmap23
 /hugetlb/hugemmap/hugemmap25
 /hugetlb/hugemmap/hugemmap26
+/hugetlb/hugemmap/hugemmap27
 /hugetlb/hugeshmat/hugeshmat01
 /hugetlb/hugeshmat/hugeshmat02
 /hugetlb/hugeshmat/hugeshmat03
diff --git a/testcases/kernel/mem/hugetlb/hugemmap/hugemmap27.c b/testcases/kernel/mem/hugetlb/hugemmap/hugemmap27.c
new file mode 100644
index 000000000..243a8abf7
--- /dev/null
+++ b/testcases/kernel/mem/hugetlb/hugemmap/hugemmap27.c
@@ -0,0 +1,136 @@
+// SPDX-License-Identifier: LGPL-2.1-or-later
+/*
+ * Copyright (C) 2013 LG Electronics.
+ * Author: Joonsoo Kim
+ */
+
+/*\
+ * [Description]
+ *
+ * Test to preserve a reserved page against no-reserved mapping. If all
+ * hugepages are reserved, access to no-reserved shared mapping cause a
+ * process die, instead of stealing a hugepage which is reserved for other
+ * process.
+ */
+
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <sys/mount.h>
+#include <limits.h>
+#include <sys/param.h>
+#include <setjmp.h>
+#include <sys/types.h>
+
+#include "tst_test.h"
+
+#ifndef barrier
+# ifdef mb
+	/* Redefining the memory barrier */
+#   define barrier() mb()
+# else
+#   define barrier() __asm__ __volatile__ ("" : : : "memory")
+# endif
+#endif
+
+#define MNTPOINT "hugetlbfs/"
+static long hpage_size;
+static int fd1 = -1, fd2 = -1;
+static sigjmp_buf sig_escape;
+static void *sig_expected = MAP_FAILED;
+
+static void sig_handler(int signum, siginfo_t *si, void *uc)
+{
+	(void)uc;
+	if (signum == SIGBUS) {
+		if (si->si_addr == sig_expected)
+			siglongjmp(sig_escape, 1);
+		tst_res(TFAIL, "SIGBUS somewhere unexpected: %p (expected: %p)",
+				si->si_addr, sig_expected);
+	} else
+		tst_res(TFAIL, "Unexpected signal %s", strsignal(signum));
+}
+
+static int test_write(void *p)
+{
+	volatile char *pl = p;
+
+	if (sigsetjmp(sig_escape, 1)) {
+		/* We got a SIGBUS */
+		return 1;
+	}
+
+	sig_expected = p;
+	barrier();
+	*pl = 's';
+	return 0;
+}
+
+static void run_test(void)
+{
+	int nr_hugepages;
+	int surp_hugepages;
+	int ret;
+	char *p, *q;
+	struct sigaction sa = {
+		.sa_sigaction = sig_handler,
+		.sa_flags = SA_SIGINFO,
+	};
+
+	nr_hugepages = SAFE_READ_MEMINFO(MEMINFO_HPAGE_FREE);
+
+	SAFE_SIGACTION(SIGBUS, &sa, NULL);
+
+	p = SAFE_MMAP(NULL, hpage_size * nr_hugepages,
+		PROT_READ | PROT_WRITE, MAP_SHARED, fd1, 0);
+
+	tst_res(TINFO, "Reserve all hugepages %d", nr_hugepages);
+
+	q = SAFE_MMAP(NULL, hpage_size,
+		PROT_READ | PROT_WRITE, MAP_SHARED | MAP_NORESERVE, fd2, 0);
+
+	tst_res(TINFO, "Write to %p to steal reserved page", q);
+
+	surp_hugepages = SAFE_READ_MEMINFO(MEMINFO_HPAGE_SURP);
+	ret = test_write(q);
+	if (ret == 1) {
+		tst_res(TPASS, "Successful with SIGSEGV received");
+		goto cleanup;
+	}
+	/* Provisioning succeeded because of overcommit */
+	if (SAFE_READ_MEMINFO(MEMINFO_HPAGE_SURP) ==
+			surp_hugepages + 1) {
+		tst_res(TPASS, "Successful because of surplus pages");
+		goto cleanup;
+	}
+
+	tst_res(TFAIL, "Steal reserved page");
+cleanup:
+	SAFE_MUNMAP(p, hpage_size * nr_hugepages);
+	SAFE_MUNMAP(q, hpage_size);
+}
+
+static void setup(void)
+{
+	hpage_size = SAFE_READ_MEMINFO(MEMINFO_HPAGE_SIZE)*1024;
+	fd1 = tst_creat_unlinked(MNTPOINT, 0);
+	fd2 = tst_creat_unlinked(MNTPOINT, 0);
+}
+
+static void cleanup(void)
+{
+	if (fd1 >= 0)
+		SAFE_CLOSE(fd1);
+	if (fd2 >= 0)
+		SAFE_CLOSE(fd2);
+}
+
+static struct tst_test test = {
+	.needs_root = 1,
+	.mntpoint = MNTPOINT,
+	.needs_hugetlbfs = 1,
+	.needs_tmpdir = 1,
+	.setup = setup,
+	.cleanup = cleanup,
+	.test_all = run_test,
+	.hugepages = {2, TST_NEEDS},
+};
-- 
2.31.1


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