PM: hibernate: Use __get_safe_page() rather than touching the list

commit f0c7183008b41e92fa676406d87f18773724b48b upstream.

We found at least one situation where the safe pages list was empty and
get_buffer() would gladly try to use a NULL pointer.

Signed-off-by: Brian Geffon <bgeffon@google.com>
Fixes: 8357376d3df2 ("[PATCH] swsusp: Improve handling of highmem")
Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
index 0f12e0a..59ffdff 100644 (file)
--- a/kernel/power/snapshot.c
+++ b/kernel/power/snapshot.c
@@ -2545,8 +2545,9 @@ static void *get_highmem_page_buffer(struct page *page,
                pbe->copy_page = tmp;
        } else {
                /* Copy of the page will be stored in normal memory */
-               kaddr = safe_pages_list;
-               safe_pages_list = safe_pages_list->next;
+               kaddr = __get_safe_page(ca->gfp_mask);
+               if (!kaddr)
+                       return ERR_PTR(-ENOMEM);
                pbe->copy_page = virt_to_page(kaddr);
        }
        pbe->next = highmem_pblist;
@@ -2750,8 +2751,9 @@ static void *get_buffer(struct memory_bitmap *bm, struct chain_allocator *ca)
                return ERR_PTR(-ENOMEM);
        }
        pbe->orig_address = page_address(page);
-       pbe->address = safe_pages_list;
-       safe_pages_list = safe_pages_list->next;
+       pbe->address = __get_safe_page(ca->gfp_mask);
+       if (!pbe->address)
+               return ERR_PTR(-ENOMEM);
        pbe->next = restore_pblist;
        restore_pblist = pbe;
        return pbe->address;