On Tue, Oct 22, 2013 at 04:52:20PM +0300, Kirill A. Shutemov wrote: > Matthew noticed that hugetlb doesn't participate in ASLR on x86-64. > The reason is genereic hugetlb_get_unmapped_area() which is used on > x86-64. It doesn't support randomization and use bottom-up unmapped area > lookup, instead of usual top-down on x86-64. > > x86 has arch-specific hugetlb_get_unmapped_area(), but it's used only on > x86-32. > > Let's use arch-specific hugetlb_get_unmapped_area() on x86-64 too. > It fixes the issue and make hugetlb use top-down unmapped area lookup. > > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> > Cc: Matthew Wilcox <willy@xxxxxxxxxxxxxxx> Gentelmen, Could you take a look on the patch, please? It's currently in -mm to get it tested on -next, but it should go through x86 tree, I believe. > --- > arch/x86/include/asm/page.h | 1 + > arch/x86/include/asm/page_32.h | 4 ---- > arch/x86/mm/hugetlbpage.c | 9 +++------ > 3 files changed, 4 insertions(+), 10 deletions(-) > > diff --git a/arch/x86/include/asm/page.h b/arch/x86/include/asm/page.h > index c87892442e..775873d3be 100644 > --- a/arch/x86/include/asm/page.h > +++ b/arch/x86/include/asm/page.h > @@ -71,6 +71,7 @@ extern bool __virt_addr_valid(unsigned long kaddr); > #include <asm-generic/getorder.h> > > #define __HAVE_ARCH_GATE_AREA 1 > +#define HAVE_ARCH_HUGETLB_UNMAPPED_AREA > > #endif /* __KERNEL__ */ > #endif /* _ASM_X86_PAGE_H */ > diff --git a/arch/x86/include/asm/page_32.h b/arch/x86/include/asm/page_32.h > index 4d550d04b6..904f528cc8 100644 > --- a/arch/x86/include/asm/page_32.h > +++ b/arch/x86/include/asm/page_32.h > @@ -5,10 +5,6 @@ > > #ifndef __ASSEMBLY__ > > -#ifdef CONFIG_HUGETLB_PAGE > -#define HAVE_ARCH_HUGETLB_UNMAPPED_AREA > -#endif > - > #define __phys_addr_nodebug(x) ((x) - PAGE_OFFSET) > #ifdef CONFIG_DEBUG_VIRTUAL > extern unsigned long __phys_addr(unsigned long); > diff --git a/arch/x86/mm/hugetlbpage.c b/arch/x86/mm/hugetlbpage.c > index 9d980d88b7..8c9f647ff9 100644 > --- a/arch/x86/mm/hugetlbpage.c > +++ b/arch/x86/mm/hugetlbpage.c > @@ -87,9 +87,7 @@ int pmd_huge_support(void) > } > #endif > > -/* x86_64 also uses this file */ > - > -#ifdef HAVE_ARCH_HUGETLB_UNMAPPED_AREA > +#ifdef CONFIG_HUGETLB_PAGE > static unsigned long hugetlb_get_unmapped_area_bottomup(struct file *file, > unsigned long addr, unsigned long len, > unsigned long pgoff, unsigned long flags) > @@ -99,7 +97,7 @@ static unsigned long hugetlb_get_unmapped_area_bottomup(struct file *file, > > info.flags = 0; > info.length = len; > - info.low_limit = TASK_UNMAPPED_BASE; > + info.low_limit = current->mm->mmap_legacy_base; > info.high_limit = TASK_SIZE; > info.align_mask = PAGE_MASK & ~huge_page_mask(h); > info.align_offset = 0; > @@ -172,8 +170,7 @@ hugetlb_get_unmapped_area(struct file *file, unsigned long addr, > return hugetlb_get_unmapped_area_topdown(file, addr, len, > pgoff, flags); > } > - > -#endif /*HAVE_ARCH_HUGETLB_UNMAPPED_AREA*/ > +#endif /* CONFIG_HUGETLB_PAGE */ > > #ifdef CONFIG_X86_64 > static __init int setup_hugepagesz(char *opt) > -- > 1.8.4.rc3 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- Kirill A. Shutemov -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>