HWPOISON: add page flags filter

When specified, only poison pages if ((page_flags & mask) == value).

-       corrupt-filter-flags-mask
-       corrupt-filter-flags-value

This allows stress testing of many kinds of pages.

Strictly speaking, the buddy pages requires taking zone lock, to avoid
setting PG_hwpoison on a "was buddy but now allocated to someone" page.
However we can just do nothing because we set PG_locked in the beginning,
this prevents the page allocator from allocating it to someone. (It will
BUG() on the unexpected PG_locked, which is fine for hwpoison testing.)

[AK: Add select PROC_PAGE_MONITOR to satisfy dependency]

CC: Nick Piggin <npiggin@suse.de>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>

1 files changed, 20 insertions, 0 deletions

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 82ac73436d0e..22d2b2028e54 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -34,6 +34,7 @@
 #include <linux/kernel.h>
 #include <linux/mm.h>
 #include <linux/page-flags.h>
+#include <linux/kernel-page-flags.h>
 #include <linux/sched.h>
 #include <linux/ksm.h>
 #include <linux/rmap.h>
@@ -50,8 +51,12 @@ atomic_long_t mce_bad_pages __read_mostly = ATOMIC_LONG_INIT(0);
 
 u32 hwpoison_filter_dev_major = ~0U;
 u32 hwpoison_filter_dev_minor = ~0U;
+u64 hwpoison_filter_flags_mask;
+u64 hwpoison_filter_flags_value;
 EXPORT_SYMBOL_GPL(hwpoison_filter_dev_major);
 EXPORT_SYMBOL_GPL(hwpoison_filter_dev_minor);
+EXPORT_SYMBOL_GPL(hwpoison_filter_flags_mask);
+EXPORT_SYMBOL_GPL(hwpoison_filter_flags_value);
 
 static int hwpoison_filter_dev(struct page *p)
 {
@@ -83,11 +88,26 @@ static int hwpoison_filter_dev(struct page *p)
         return 0;
 }
 
+static int hwpoison_filter_flags(struct page *p)
+{
+        if (!hwpoison_filter_flags_mask)
+                return 0;
+
+        if ((stable_page_flags(p) & hwpoison_filter_flags_mask) ==
+                                    hwpoison_filter_flags_value)
+                return 0;
+        else
+                return -EINVAL;
+}
+
 int hwpoison_filter(struct page *p)
 {
         if (hwpoison_filter_dev(p))
                 return -EINVAL;
 
+        if (hwpoison_filter_flags(p))
+                return -EINVAL;
+
         return 0;
 }
 EXPORT_SYMBOL_GPL(hwpoison_filter);