x86 PAT: remove PFNMAP type on track_pfn_vma_new() error
venkatesh.pallipadi@intel.com [Sat, 10 Jan 2009 00:13:09 +0000 (16:13 -0800)]
Impact: fix (harmless) double-free of memtype entries and avoid warning

On track_pfn_vma_new() failure, reset the vm_flags so that there will be
no second cleanup happening when upper level routines call unmap_vmas().

This patch fixes part of the bug reported here:

  http://marc.info/?l=linux-kernel&m=123108883716357&w=2

Specifically the error message:

  X:5010 freeing invalid memtype d0000000-d0101000

Is due to multiple frees on error path, will not happen with the patch below.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

mm/memory.c

index c2d4c47..d3ee2ea 100644 (file)
@@ -1672,8 +1672,14 @@ int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
        vma->vm_flags |= VM_IO | VM_RESERVED | VM_PFNMAP;
 
        err = track_pfn_vma_new(vma, prot, pfn, PAGE_ALIGN(size));
-       if (err)
+       if (err) {
+               /*
+                * To indicate that track_pfn related cleanup is not
+                * needed from higher level routine calling unmap_vmas
+                */
+               vma->vm_flags &= ~(VM_IO | VM_RESERVED | VM_PFNMAP);
                return -EINVAL;
+       }
 
        BUG_ON(addr >= end);
        pfn -= addr >> PAGE_SHIFT;