Messages in this thread | | | Date | Fri, 2 Jul 2004 11:20:12 +1000 | From | David Gibson <> | Subject | Re: [BUG] hugetlb MAP_PRIVATE mapping vs /dev/zero |
| |
On Thu, Jul 01, 2004 at 08:29:18PM +0400, Oleg Nesterov wrote: > Hello. > > Hugetlbfs mmap with MAP_PRIVATE becomes MAP_SHARED > silently, but vma->vm_flags have no VM_SHARED bit. > I think it make sense to forbid MAP_PRIVATE in > hugetlbfs_file_mmap() because it may confuse user > space applications. But the real bug is that reading > from /dev/zero into hugetlb will do: > > read_zero() > read_zero_pagealigned() > if (vma->vm_flags & VM_SHARED) > break; // OK if MAP_PRIVATE > zap_page_range(); > zeromap_page_range(); > > We can fix hugetlbfs_file_mmap() or read_zero_pagealigned() > or both.
Err... surely we need to fix both, yes?
-- David Gibson | For every complex problem there is a david AT gibson.dropbear.id.au | solution which is simple, neat and | wrong. http://www.ozlabs.org/people/dgibson - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |