Merge remote-tracking branches 'asoc/fix/rockchip', 'asoc/fix/rt5645', 'asoc/fix...

[sfrench/cifs-2.6.git] / mm / vmalloc.c

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 34a1c3e46ed72594b499e7f61e8aacdd4c5fe818..ecc97f74ab182fe9aeb7d7eda5166dfdb5b03095 100644 (file)
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -287,10 +287,21 @@ struct page *vmalloc_to_page(const void *vmalloc_addr)
        if (p4d_none(*p4d))
                return NULL;
        pud = pud_offset(p4d, addr);
-       if (pud_none(*pud))
+
+       /*
+        * Don't dereference bad PUD or PMD (below) entries. This will also
+        * identify huge mappings, which we may encounter on architectures
+        * that define CONFIG_HAVE_ARCH_HUGE_VMAP=y. Such regions will be
+        * identified as vmalloc addresses by is_vmalloc_addr(), but are
+        * not [unambiguously] associated with a struct page, so there is
+        * no correct value to return for them.
+        */
+       WARN_ON_ONCE(pud_bad(*pud));
+       if (pud_none(*pud) || pud_bad(*pud))
                return NULL;
        pmd = pmd_offset(pud, addr);
-       if (pmd_none(*pmd))
+       WARN_ON_ONCE(pmd_bad(*pmd));
+       if (pmd_none(*pmd) || pmd_bad(*pmd))
                return NULL;
 
        ptep = pte_offset_map(pmd, addr);