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* [PATCH] x86, mm: get ASLR work for hugetlb mappings
@ 2013-10-22 13:52 Kirill A. Shutemov
  2013-10-22 15:21 ` Dave Hansen
                   ` (2 more replies)
  0 siblings, 3 replies; 6+ messages in thread
From: Kirill A. Shutemov @ 2013-10-22 13:52 UTC (permalink / raw)
  To: Andrew Morton, Thomas Gleixner, Ingo Molnar, H. Peter Anvin
  Cc: Nadia Yvette Chambers, Naoya Horiguchi, x86, linux-kernel,
	linux-mm, Kirill A. Shutemov, Matthew Wilcox

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@linux.intel.com>
Cc: Matthew Wilcox <willy@linux.intel.com>
---
 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


^ permalink raw reply related	[flat|nested] 6+ messages in thread
* Re: [PATCH] x86, mm: get ASLR work for hugetlb mappings
  2013-10-22 13:52 [PATCH] x86, mm: get ASLR work for hugetlb mappings Kirill A. Shutemov
@ 2013-10-22 15:21 ` Dave Hansen
  2013-10-22 17:52   ` Kirill A. Shutemov
  2013-11-04 10:41 ` Kirill A. Shutemov
  2013-11-11 13:45 ` Kirill A. Shutemov
  2 siblings, 1 reply; 6+ messages in thread
From: Dave Hansen @ 2013-10-22 15:21 UTC (permalink / raw)
  To: Kirill A. Shutemov, Andrew Morton, Thomas Gleixner, Ingo Molnar,
	H. Peter Anvin
  Cc: Nadia Yvette Chambers, Naoya Horiguchi, x86, linux-kernel,
	linux-mm, Matthew Wilcox

On 10/22/2013 06:52 AM, 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.

I have to wonder if this was on purpose in order to keep the large and
small mappings separate.  We don't *have* to keep them separate this, of
course, but it makes me wonder.

> 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.

Shouldn't we fix the generic code instead of further specializing the
x86 stuff?

In any case, you probably also want to run this through: the
libhugetlbfs tests:

http://sourceforge.net/p/libhugetlbfs/code/ci/master/tree/tests/

^ permalink raw reply	[flat|nested] 6+ messages in thread
* Re: [PATCH] x86, mm: get ASLR work for hugetlb mappings
  2013-10-22 15:21 ` Dave Hansen
@ 2013-10-22 17:52   ` Kirill A. Shutemov
  0 siblings, 0 replies; 6+ messages in thread
From: Kirill A. Shutemov @ 2013-10-22 17:52 UTC (permalink / raw)
  To: Dave Hansen
  Cc: Kirill A. Shutemov, Andrew Morton, Thomas Gleixner, Ingo Molnar,
	H. Peter Anvin, Nadia Yvette Chambers, Naoya Horiguchi, x86,
	linux-kernel, linux-mm, Matthew Wilcox

Dave Hansen wrote:
> On 10/22/2013 06:52 AM, 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.
> 
> I have to wonder if this was on purpose in order to keep the large and
> small mappings separate.  We don't *have* to keep them separate this, of
> course, but it makes me wonder.

I haven't seen any evidence that it's on purpose, but who knows...

In x86-specific hugetlb_get_unmapped_area() there's explicit check what is
mm->get_unmapped_area top-down or bottom-up, and doing the same.

> > 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.
> 
> Shouldn't we fix the generic code instead of further specializing the
> x86 stuff?

For that we need to modify info.low_limit to mm->mmap_legacy_base (which
is x86 specific, no-go) or switch to top-down and set info.high_limit to
mm->mmap_base.

I don't know how it can affect other architectures.

> In any case, you probably also want to run this through: the
> libhugetlbfs tests:
> 
> http://sourceforge.net/p/libhugetlbfs/code/ci/master/tree/tests/

I've got the same fail list for upstream and patched kernel, so no
regression was found.

********** TEST SUMMARY  
*                      2M            
*                      32-bit 64-bit 
*     Total testcases:   107    110   
*             Skipped:     0      0   
*                PASS:    98    108   
*                FAIL:     2      2   
*    Killed by signal:     7      0   
*   Bad configuration:     0      0   
*       Expected FAIL:     0      0   
*     Unexpected PASS:     0      0   
* Strange test result:     0      0   
**********

-- 
 Kirill A. Shutemov

^ permalink raw reply	[flat|nested] 6+ messages in thread
* RE: [PATCH] x86, mm: get ASLR work for hugetlb mappings
  2013-10-22 13:52 [PATCH] x86, mm: get ASLR work for hugetlb mappings Kirill A. Shutemov
  2013-10-22 15:21 ` Dave Hansen
@ 2013-11-04 10:41 ` Kirill A. Shutemov
  2013-11-04 21:09   ` Andrew Morton
  2013-11-11 13:45 ` Kirill A. Shutemov
  2 siblings, 1 reply; 6+ messages in thread
From: Kirill A. Shutemov @ 2013-11-04 10:41 UTC (permalink / raw)
  To: Andrew Morton
  Cc: Thomas Gleixner, Ingo Molnar, H. Peter Anvin,
	Nadia Yvette Chambers, Naoya Horiguchi, x86, linux-kernel,
	linux-mm, Kirill A. Shutemov, Matthew Wilcox

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@linux.intel.com>
> Cc: Matthew Wilcox <willy@linux.intel.com>

Andrew, any comments?

-- 
 Kirill A. Shutemov

^ permalink raw reply	[flat|nested] 6+ messages in thread
* Re: [PATCH] x86, mm: get ASLR work for hugetlb mappings
  2013-11-04 10:41 ` Kirill A. Shutemov
@ 2013-11-04 21:09   ` Andrew Morton
  0 siblings, 0 replies; 6+ messages in thread
From: Andrew Morton @ 2013-11-04 21:09 UTC (permalink / raw)
  To: Kirill A. Shutemov
  Cc: Thomas Gleixner, Ingo Molnar, H. Peter Anvin,
	Nadia Yvette Chambers, Naoya Horiguchi, x86, linux-kernel,
	linux-mm, Matthew Wilcox

On Mon,  4 Nov 2013 12:41:52 +0200 (EET) "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> wrote:

> 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@linux.intel.com>
> > Cc: Matthew Wilcox <willy@linux.intel.com>
> 
> Andrew, any comments?

whome?  I'm convinced, but it's an x86 patch.  I tossed it in there so
it gets a bit of linux-next exposure.


^ permalink raw reply	[flat|nested] 6+ messages in thread
* Re: [PATCH] x86, mm: get ASLR work for hugetlb mappings
  2013-10-22 13:52 [PATCH] x86, mm: get ASLR work for hugetlb mappings Kirill A. Shutemov
  2013-10-22 15:21 ` Dave Hansen
  2013-11-04 10:41 ` Kirill A. Shutemov
@ 2013-11-11 13:45 ` Kirill A. Shutemov
  2 siblings, 0 replies; 6+ messages in thread
From: Kirill A. Shutemov @ 2013-11-11 13:45 UTC (permalink / raw)
  To: Thomas Gleixner, Ingo Molnar, H. Peter Anvin
  Cc: Andrew Morton, Nadia Yvette Chambers, Naoya Horiguchi, x86,
	linux-kernel, linux-mm, Matthew Wilcox, Kirill A. Shutemov

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@linux.intel.com>
> Cc: Matthew Wilcox <willy@linux.intel.com>

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
> 
> --
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-- 
 Kirill A. Shutemov

^ permalink raw reply	[flat|nested] 6+ messages in thread
end of thread, other threads:[~2013-11-11 14:41 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2013-10-22 13:52 [PATCH] x86, mm: get ASLR work for hugetlb mappings Kirill A. Shutemov
2013-10-22 15:21 ` Dave Hansen
2013-10-22 17:52   ` Kirill A. Shutemov
2013-11-04 10:41 ` Kirill A. Shutemov
2013-11-04 21:09   ` Andrew Morton
2013-11-11 13:45 ` Kirill A. Shutemov

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