Add a writable attribute in debugfs to trigger a
W^X pages check at any time.
To trigger the test, just echo any numeric value into
/sys/kernel/debug/check_wx_pages
The result is provided into dmesg.
Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
---
mm/ptdump.c | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)
diff --git a/mm/ptdump.c b/mm/ptdump.c
index 03c1bdae4a43..e154099c2584 100644
--- a/mm/ptdump.c
+++ b/mm/ptdump.c
@@ -1,6 +1,7 @@
// SPDX-License-Identifier: GPL-2.0
#include <linux/pagewalk.h>
+#include <linux/debugfs.h>
#include <linux/ptdump.h>
#include <linux/kasan.h>
@@ -163,3 +164,21 @@ void ptdump_walk_pgd(struct ptdump_state *st, struct mm_struct *mm, pgd_t *pgd)
/* Flush out the last page */
st->note_page(st, 0, -1, 0);
}
+
+static int check_wx_debugfs_set(void *data, u64 val)
+{
+ ptdump_check_wx();
+
+ return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(check_wx_fops, NULL, check_wx_debugfs_set, "%llu\n");
+
+static int ptdump_debugfs_init(void)
+{
+ debugfs_create_file("check_wx_pages", 0200, NULL, NULL, &check_wx_fops);
+
+ return 0;
+}
+
+device_initcall(ptdump_debugfs_init);
--
2.41.0
