[PATCH] x86_64: When checking vmalloc mappings don't use pte_page

The PTEs can point to ioremap mappings too, and these are often outside
mem_map.  The NUMA hash page lookup functions cannot handle out of bounds
accesses properly.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/arch/x86_64/mm/fault.c b/arch/x86_64/mm/fault.c
index e033092..5d6b211 100644 (file)
--- a/arch/x86_64/mm/fault.c
+++ b/arch/x86_64/mm/fault.c
@@ -234,6 +234,8 @@ static noinline void pgtable_bad(unsigned long address, struct pt_regs *regs,
 
 /*
  * Handle a fault on the vmalloc or module mapping area
 
 /*
  * Handle a fault on the vmalloc or module mapping area

+ *
+ * This assumes no large pages in there.

  */
 static int vmalloc_fault(unsigned long address)
 {
  */
 static int vmalloc_fault(unsigned long address)
 {


@@ -272,7 +274,10 @@ static int vmalloc_fault(unsigned long address)
        if (!pte_present(*pte_ref))
                return -1;
        pte = pte_offset_kernel(pmd, address);
        if (!pte_present(*pte_ref))
                return -1;
        pte = pte_offset_kernel(pmd, address);

-       if (!pte_present(*pte) || pte_page(*pte) != pte_page(*pte_ref))
+       /* Don't use pte_page here, because the mappings can point
+          outside mem_map, and the NUMA hash lookup cannot handle
+          that. */
+       if (!pte_present(*pte) || pte_pfn(*pte) != pte_pfn(*pte_ref))

                BUG();
        __flush_tlb_all();
        return 0;
                BUG();
        __flush_tlb_all();
        return 0;


@@ -346,7 +351,9 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long error_code)
         * protection error (error_code & 1) == 0.
         */
        if (unlikely(address >= TASK_SIZE)) {
         * protection error (error_code & 1) == 0.
         */
        if (unlikely(address >= TASK_SIZE)) {

-               if (!(error_code & 5)) {
+               if (!(error_code & 5) &&
+                     ((address >= VMALLOC_START && address < VMALLOC_END) ||
+                      (address >= MODULES_VADDR && address < MODULES_END))) {

                        if (vmalloc_fault(address) < 0)
                                goto bad_area_nosemaphore;
                        return;
                        if (vmalloc_fault(address) < 0)
                                goto bad_area_nosemaphore;
                        return;