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remap_file_pages: correctly handle the case of a NULL vm_ops pointer

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In commit 0b173bc4da ("mm: kill vma flag VM_CAN_NONLINEAR") we
replaced the VM_CAN_NONLINEAR test with checking whether the mapping has
a '->remap_pages()' vm operation, but there is no guarantee that there
it even has a vm_ops pointer at all.

Add the appropriate test for NULL vm_ops.

Reported-by: Sasha Levin <levinsasha928@gmail.com>
Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Linus Torvalds 2012-10-19 13:37:57 -07:00
parent 17dbe27d84
commit deb521c44f
1 changed files with 1 additions and 1 deletions
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2
mm/fremap.c
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@ -169,7 +169,7 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size,
if (vma->vm_private_data && !(vma->vm_flags & VM_NONLINEAR))
goto out;
if (!vma->vm_ops->remap_pages)
if (!vma->vm_ops || !vma->vm_ops->remap_pages)
goto out;
if (start < vma->vm_start || start + size > vma->vm_end)