Introduce is_vmalloc_or_module_addr() and use with DEBUG_VIRTUAL

Impact: crash on module insertion with CONFIG_DEBUG_VIRTUAL

We would incorrectly BUG due to:

   VIRTUAL_BUG_ON(!is_vmalloc_addr(vmalloc_addr) &&
   	          !is_module_address(addr));

... because, at least on x86-64, is_module_address() doesn't do what
it should.  This patch introduces is_vmalloc_or_module_addr(), which
is what we really want anyway, and uses it instead.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

1 files changed, 16 insertions, 2 deletions

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index bba06c41fc59..f018d7e0addb 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -168,6 +168,21 @@ int map_vm_area(struct vm_struct *area, pgprot_t prot, struct page ***pages)
 }
 EXPORT_SYMBOL_GPL(map_vm_area);
 
+static inline int is_vmalloc_or_module_addr(const void *x)
+{
+        /*
+         * x86-64 and sparc64 put modules in a special place,
+         * and fall back on vmalloc() if that fails. Others
+         * just put it in the vmalloc space.
+         */
+#if defined(CONFIG_MODULES) && defined(MODULES_VADDR)
+        unsigned long addr = (unsigned long)x;
+        if (addr >= MODULES_VADDR && addr < MODULES_END)
+                return 1;
+#endif
+        return is_vmalloc_addr(x);
+}
+
 /*
  * Map a vmalloc()-space virtual address to the physical page.
  */
@@ -184,8 +199,7 @@ struct page *vmalloc_to_page(const void *vmalloc_addr)
          * XXX we might need to change this if we add VIRTUAL_BUG_ON for
          * architectures that do not vmalloc module space
          */
-        VIRTUAL_BUG_ON(!is_vmalloc_addr(vmalloc_addr) &&
-                        !is_module_address(addr));
+        VIRTUAL_BUG_ON(!is_vmalloc_or_module_addr(vmalloc_addr));
 
         if (!pgd_none(*pgd)) {
                 pud = pud_offset(pgd, addr);