1 files changed, 15 insertions, 2 deletions

diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index bd61ed13f9cf..4119379f80ff 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -688,6 +688,15 @@ static int change_page_attr_set_clr(unsigned long addr, int numpages,
         if (!pgprot_val(mask_set) && !pgprot_val(mask_clr))
                 return 0;
 
+        /* Ensure we are PAGE_SIZE aligned */
+        if (addr & ~PAGE_MASK) {
+                addr &= PAGE_MASK;
+                /*
+                 * People should not be passing in unaligned addresses:
+                 */
+                WARN_ON_ONCE(1);
+        }
+
         cpa.vaddr = addr;
         cpa.numpages = numpages;
         cpa.mask_set = mask_set;
@@ -861,8 +870,12 @@ void kernel_map_pages(struct page *page, int numpages, int enable)
                 return;
 
         /*
-         * The return value is ignored - the calls cannot fail,
-         * large pages are disabled at boot time:
+         * The return value is ignored as the calls cannot fail.
+         * Large pages are kept enabled at boot time, and are
+         * split up quickly with DEBUG_PAGEALLOC. If a splitup
+         * fails here (due to temporary memory shortage) no damage
+         * is done because we just keep the largepage intact up
+         * to the next attempt when it will likely be split up:
          */
         if (enable)
                 __set_pages_p(page, numpages);