Messages in this thread | | | Date | Tue, 14 Nov 2017 21:54:52 +0100 (CET) | From | Thomas Gleixner <> | Subject | Re: [PATCHv2 1/2] x86/mm: Do not allow non-MAP_FIXED mapping across DEFAULT_MAP_WINDOW border |
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On Tue, 14 Nov 2017, Kirill A. Shutemov wrote:
> On Tue, Nov 14, 2017 at 05:01:50PM +0100, Thomas Gleixner wrote: > > @@ -198,11 +199,14 @@ arch_get_unmapped_area_topdown(struct fi > > /* requesting a specific address */ > > if (addr) { > > addr = PAGE_ALIGN(addr); > > + if (!mmap_address_hint_valid(addr, len)) > > + goto get_unmapped_area; > > + > > Here and in hugetlb_get_unmapped_area(), we should align the addr after > the check, not before. Otherwise the alignment itself can bring us over > the borderline as we align up.
Hmm, then I wonder whether the next check against vm_start_gap() which checks against the aligned address is correct:
addr = PAGE_ALIGN(addr); vma = find_vma(mm, addr);
if (end - len >= addr && (!vma || addr + len <= vm_start_gap(vma))) return addr;
Thanks,
tglx
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