Documentation/filesystems/proc.txt: add more description for maps/smaps

[cascardo/linux.git] / mm / memory.c

diff --git a/mm/memory.c b/mm/memory.c
index f1a6804..fc1987d 100644 (file)
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1649,10 +1649,14 @@ EXPORT_SYMBOL(vm_insert_pfn_prot);
 int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
                        pfn_t pfn)
 {
+       pgprot_t pgprot = vma->vm_page_prot;
+
        BUG_ON(!(vma->vm_flags & VM_MIXEDMAP));
 
        if (addr < vma->vm_start || addr >= vma->vm_end)
                return -EFAULT;
+       if (track_pfn_insert(vma, &pgprot, pfn))
+               return -EINVAL;
 
        /*
         * If we don't have pte special, then we have to use the pfn_valid()
@@ -1670,9 +1674,9 @@ int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
                 * result in pfn_t_has_page() == false.
                 */
                page = pfn_to_page(pfn_t_to_pfn(pfn));
-               return insert_page(vma, addr, page, vma->vm_page_prot);
+               return insert_page(vma, addr, page, pgprot);
        }
-       return insert_pfn(vma, addr, pfn, vma->vm_page_prot);
+       return insert_pfn(vma, addr, pfn, pgprot);
 }
 EXPORT_SYMBOL(vm_insert_mixed);
 
@@ -3658,6 +3662,19 @@ int handle_mm_fault(struct vm_area_struct *vma, unsigned long address,
                         mem_cgroup_oom_synchronize(false);
        }
 
+       /*
+        * This mm has been already reaped by the oom reaper and so the
+        * refault cannot be trusted in general. Anonymous refaults would
+        * lose data and give a zero page instead e.g. This is especially
+        * problem for use_mm() because regular tasks will just die and
+        * the corrupted data will not be visible anywhere while kthread
+        * will outlive the oom victim and potentially propagate the date
+        * further.
+        */
+       if (unlikely((current->flags & PF_KTHREAD) && !(ret & VM_FAULT_ERROR)
+                               && test_bit(MMF_UNSTABLE, &vma->vm_mm->flags)))
+               ret = VM_FAULT_SIGBUS;
+
        return ret;
 }
 EXPORT_SYMBOL_GPL(handle_mm_fault);