1 files changed, 27 insertions, 0 deletions

diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c
index bbcc185062bb..d29d869abec1 100644
--- a/fs/proc/kcore.c
+++ b/fs/proc/kcore.c
@@ -54,6 +54,28 @@ static LIST_HEAD(kclist_head);
 static DECLARE_RWSEM(kclist_lock);
 static int kcore_need_update = 1;
 
+/*
+ * Returns > 0 for RAM pages, 0 for non-RAM pages, < 0 on error
+ * Same as oldmem_pfn_is_ram in vmcore
+ */
+static int (*mem_pfn_is_ram)(unsigned long pfn);
+
+int __init register_mem_pfn_is_ram(int (*fn)(unsigned long pfn))
+{
+        if (mem_pfn_is_ram)
+                return -EBUSY;
+        mem_pfn_is_ram = fn;
+        return 0;
+}
+
+static int pfn_is_ram(unsigned long pfn)
+{
+        if (mem_pfn_is_ram)
+                return mem_pfn_is_ram(pfn);
+        else
+                return 1;
+}
+
 /* This doesn't grab kclist_lock, so it should only be used at init time. */
 void __init kclist_add(struct kcore_list *new, void *addr, size_t size,
                        int type)
@@ -465,6 +487,11 @@ read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos)
                                 goto out;
                         }
                         m = NULL;       /* skip the list anchor */
+                } else if (!pfn_is_ram(__pa(start) >> PAGE_SHIFT)) {
+                        if (clear_user(buffer, tsz)) {
+                                ret = -EFAULT;
+                                goto out;
+                        }
                 } else if (m->type == KCORE_VMALLOC) {
                         vread(buf, (char *)start, tsz);
                         /* we have to zero-fill user buffer even if no read */