[LTP] [PATCH v3] mmap22.c: Test for new MAP_DROPPABLE flag for mmap

[Wei Gao]

Signed-off-by: Wei Gao <wegao@suse.com>
---
 include/lapi/mmap.h                       |  4 +
 runtest/syscalls                          |  1 +
 testcases/kernel/syscalls/mmap/.gitignore |  1 +
 testcases/kernel/syscalls/mmap/mmap22.c   | 95 +++++++++++++++++++++++
 4 files changed, 101 insertions(+)
 create mode 100644 testcases/kernel/syscalls/mmap/mmap22.c

diff --git a/include/lapi/mmap.h b/include/lapi/mmap.h
index ea9730586..248b64564 100644
--- a/include/lapi/mmap.h
+++ b/include/lapi/mmap.h
@@ -87,6 +87,10 @@
 # define MADV_PAGEOUT	21
 #endif
 
+#ifndef MAP_DROPPABLE
+# define MAP_DROPPABLE 0x08
+#endif
+
 #ifndef MAP_FIXED_NOREPLACE
 
 #ifdef __alpha__
diff --git a/runtest/syscalls b/runtest/syscalls
index 932b7030c..e369536ea 100644
--- a/runtest/syscalls
+++ b/runtest/syscalls
@@ -844,6 +844,7 @@ mmap19 mmap19
 mmap20 mmap20
 mmap21_01 mmap21 -m 1
 mmap21_02 mmap21
+mmap22 mmap22
 
 modify_ldt01 modify_ldt01
 modify_ldt02 modify_ldt02
diff --git a/testcases/kernel/syscalls/mmap/.gitignore b/testcases/kernel/syscalls/mmap/.gitignore
index 850284d86..075be933d 100644
--- a/testcases/kernel/syscalls/mmap/.gitignore
+++ b/testcases/kernel/syscalls/mmap/.gitignore
@@ -18,3 +18,4 @@
 /mmap19
 /mmap20
 /mmap21
+/mmap22
diff --git a/testcases/kernel/syscalls/mmap/mmap22.c b/testcases/kernel/syscalls/mmap/mmap22.c
new file mode 100644
index 000000000..31414896c
--- /dev/null
+++ b/testcases/kernel/syscalls/mmap/mmap22.c
@@ -0,0 +1,95 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2025 Wei Gao <wegao@suse.com>
+ */
+
+/*\
+ * [Description]
+ *
+ * Test mmap(2) with MAP_DROPPABLE flag.
+ *
+ * Test base on kernel selftests/mm/droppable.c
+ */
+
+#define _GNU_SOURCE
+#include <errno.h>
+#include <stdio.h>
+#include <sys/types.h>
+#include "tst_test.h"
+#include "lapi/mmap.h"
+
+#define MEM_LIMIT (256 * TST_MB)
+#define ALLOC_SIZE (128 * TST_MB)
+
+static struct tst_cg_group *cg_child;
+
+static void test_mmap(void)
+{
+	size_t alloc_size = ALLOC_SIZE;
+	size_t page_size = getpagesize();
+	void *alloc;
+	pid_t child;
+
+	cg_child = tst_cg_group_mk(tst_cg, "child");
+	SAFE_CG_PRINTF(tst_cg, "memory.max", "%d", MEM_LIMIT);
+	SAFE_CG_PRINTF(cg_child, "cgroup.procs", "%d", getpid());
+
+	alloc = SAFE_MMAP(0, alloc_size, PROT_READ | PROT_WRITE,
+			MAP_ANONYMOUS | MAP_DROPPABLE, -1, 0);
+
+	memset(alloc, 'A', alloc_size);
+	for (size_t i = 0; i < alloc_size; i += page_size) {
+		if (*(char *)(alloc + i) != 'A')
+			tst_res(TFAIL, "memset failed");
+	}
+
+	child = SAFE_FORK();
+	if (!child) {
+		for (;;)
+			*(char *)malloc(page_size) = 'B';
+	}
+
+	while (1) {
+		for (size_t i = 0; i < alloc_size; i += page_size) {
+			if (!tst_remaining_runtime())
+				tst_brk(TBROK, "MAP_DROPPABLE did not drop memory within the timeout period.");
+			if (!*(uint8_t *)(alloc + i)) {
+				tst_res(TPASS, "MAP_DROPPABLE test pass.");
+				goto kill_child;
+			}
+		}
+	}
+
+kill_child:
+	SAFE_KILL(child, SIGKILL);
+	SAFE_WAITPID(child, NULL, 0);
+	SAFE_MUNMAP(alloc, alloc_size);
+}
+
+static void setup(void)
+{
+	void *addr = mmap(0, 1, PROT_READ | PROT_WRITE,
+			MAP_ANONYMOUS | MAP_DROPPABLE, -1, 0);
+	if (addr == MAP_FAILED && errno == EINVAL)
+		tst_brk(TCONF, "MAP_DROPPABLE not support");
+}
+
+static void cleanup(void)
+{
+	if (cg_child) {
+		SAFE_CG_PRINTF(tst_cg_drain, "cgroup.procs", "%d", getpid());
+		cg_child = tst_cg_group_rm(cg_child);
+	}
+}
+
+static struct tst_test test = {
+	.test_all = test_mmap,
+	.needs_tmpdir = 1,
+	.forks_child = 1,
+	.needs_cgroup_ctrls = (const char *const []){ "memory", NULL },
+	.needs_root = 1,
+	.cleanup = cleanup,
+	.setup = setup,
+	.runtime = 30,
+	.min_mem_avail = 300,
+};
-- 
2.49.0