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>

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index bba06c41fc59ed10be118f7af24ecfa71d023c33..f018d7e0addb47133fcc6e16bd3f25ef2d3bf6d0 100644 (file)
--- 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);