HWPOISON: limit hwpoison injector to known page types

[net-next-2.6.git] / mm / hwpoison-inject.c

diff --git a/mm/hwpoison-inject.c b/mm/hwpoison-inject.c
index ac692a9b766c87cf6d8b8ccbf3cd295ed0c48ccd..2b6b3200fa65fd5a4b154d4b9717e1d459905e02 100644 (file)
--- a/mm/hwpoison-inject.c
+++ b/mm/hwpoison-inject.c
@@ -3,16 +3,53 @@
 #include <linux/debugfs.h>
 #include <linux/kernel.h>
 #include <linux/mm.h>
+#include <linux/swap.h>
+#include <linux/pagemap.h>
 #include "internal.h"
 
 static struct dentry *hwpoison_dir;
 
 static int hwpoison_inject(void *data, u64 val)
 {
+       unsigned long pfn = val;
+       struct page *p;
+       int err;
+
        if (!capable(CAP_SYS_ADMIN))
                return -EPERM;
-       printk(KERN_INFO "Injecting memory failure at pfn %Lx\n", val);
-       return __memory_failure(val, 18, 0);
+
+       if (!pfn_valid(pfn))
+               return -ENXIO;
+
+       p = pfn_to_page(pfn);
+       /*
+        * This implies unable to support free buddy pages.
+        */
+       if (!get_page_unless_zero(p))
+               return 0;
+
+       if (!PageLRU(p))
+               shake_page(p);
+       /*
+        * This implies unable to support non-LRU pages.
+        */
+       if (!PageLRU(p))
+               return 0;
+
+       /*
+        * do a racy check with elevated page count, to make sure PG_hwpoison
+        * will only be set for the targeted owner (or on a free page).
+        * We temporarily take page lock for try_get_mem_cgroup_from_page().
+        * __memory_failure() will redo the check reliably inside page lock.
+        */
+       lock_page(p);
+       err = hwpoison_filter(p);
+       unlock_page(p);
+       if (err)
+               return 0;
+
+       printk(KERN_INFO "Injecting memory failure at pfn %lx\n", pfn);
+       return __memory_failure(pfn, 18, MF_COUNT_INCREASED);
 }
 
 static int hwpoison_unpoison(void *data, u64 val)