mm: fix incorrect pfn passed to untrack_pfn() in remap_pfn_range()
We use generic hooks in remap_pfn_range() to help archs to track pfnmap
regions. The code is something like:
int remap_pfn_range()
{
...
track_pfn_remap(vma, &prot, pfn, addr, PAGE_ALIGN(size));
...
pfn -= addr >> PAGE_SHIFT;
...
untrack_pfn(vma, pfn, PAGE_ALIGN(size));
...
}
Here we can easily find the pfn is changed but not recovered before
untrack_pfn() is called. That's incorrect.
There are no known runtime effects - this is from inspection.
Signed-off-by: Yongji Xie <xyjxie@linux.vnet.ibm.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/memory.c b/mm/memory.c
index 07493e3..007c72a 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1744,6 +1744,7 @@
unsigned long next;
unsigned long end = addr + PAGE_ALIGN(size);
struct mm_struct *mm = vma->vm_mm;
+ unsigned long remap_pfn = pfn;
int err;
/*
@@ -1770,7 +1771,7 @@
vma->vm_pgoff = pfn;
}
- err = track_pfn_remap(vma, &prot, pfn, addr, PAGE_ALIGN(size));
+ err = track_pfn_remap(vma, &prot, remap_pfn, addr, PAGE_ALIGN(size));
if (err)
return -EINVAL;
@@ -1789,7 +1790,7 @@
} while (pgd++, addr = next, addr != end);
if (err)
- untrack_pfn(vma, pfn, PAGE_ALIGN(size));
+ untrack_pfn(vma, remap_pfn, PAGE_ALIGN(size));
return err;
}