* [PATCH] x86/mm: Fix ELF_ET_DYN_BASE for 5-level paging
@ 2017-11-07 10:38 Kirill A. Shutemov
2017-11-09 10:38 ` Kirill A. Shutemov
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Kirill A. Shutemov @ 2017-11-07 10:38 UTC (permalink / raw)
To: Ingo Molnar, Andrew Morton
Cc: linux-mm, linux-kernel, Kirill A. Shutemov, Kees Cook,
Ingo Molnar, H. Peter Anvin, Thomas Gleixner, Nicholas Piggin
On machines with 5-level paging we don't want to allocate mapping above
47-bit unless user explicitly asked for it. See b569bab78d8d ("x86/mm:
Prepare to expose larger address space to userspace") for details.
c715b72c1ba4 ("mm: revert x86_64 and arm64 ELF_ET_DYN_BASE base
changes") broke the behaviour. After the commit elf binary and heap got
mapped above 47-bits.
Let's fix this.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Fixes: c715b72c1ba4 ("mm: revert x86_64 and arm64 ELF_ET_DYN_BASE base changes")
Cc: Kees Cook <keescook@chromium.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Nicholas Piggin <npiggin@gmail.com>
---
arch/x86/include/asm/elf.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h
index c1a125e47ff3..3a091cea36c5 100644
--- a/arch/x86/include/asm/elf.h
+++ b/arch/x86/include/asm/elf.h
@@ -253,7 +253,7 @@ extern int force_personality32;
* space open for things that want to use the area for 32-bit pointers.
*/
#define ELF_ET_DYN_BASE (mmap_is_ia32() ? 0x000400000UL : \
- (TASK_SIZE / 3 * 2))
+ (DEFAULT_MAP_WINDOW / 3 * 2))
/* This yields a mask that user programs can use to figure out what
instruction set this CPU supports. This could be done in user space,
--
2.14.2
--
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^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] x86/mm: Fix ELF_ET_DYN_BASE for 5-level paging
2017-11-07 10:38 [PATCH] x86/mm: Fix ELF_ET_DYN_BASE for 5-level paging Kirill A. Shutemov
@ 2017-11-09 10:38 ` Kirill A. Shutemov
2017-11-09 15:38 ` Michal Hocko
2017-11-09 17:12 ` Thomas Gleixner
2 siblings, 0 replies; 4+ messages in thread
From: Kirill A. Shutemov @ 2017-11-09 10:38 UTC (permalink / raw)
To: Ingo Molnar, Andrew Morton, Linus Torvalds
Cc: Kirill A. Shutemov, linux-mm, linux-kernel, Kees Cook,
Ingo Molnar, H. Peter Anvin, Thomas Gleixner, Nicholas Piggin
On Tue, Nov 07, 2017 at 01:38:04PM +0300, Kirill A. Shutemov wrote:
> On machines with 5-level paging we don't want to allocate mapping above
> 47-bit unless user explicitly asked for it. See b569bab78d8d ("x86/mm:
> Prepare to expose larger address space to userspace") for details.
>
> c715b72c1ba4 ("mm: revert x86_64 and arm64 ELF_ET_DYN_BASE base
> changes") broke the behaviour. After the commit elf binary and heap got
> mapped above 47-bits.
>
> Let's fix this.
>
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> Fixes: c715b72c1ba4 ("mm: revert x86_64 and arm64 ELF_ET_DYN_BASE base changes")
> Cc: Kees Cook <keescook@chromium.org>
> Cc: Ingo Molnar <mingo@elte.hu>
> Cc: "H. Peter Anvin" <hpa@zytor.com>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Nicholas Piggin <npiggin@gmail.com>
Folks, can we please get this applied?
Without the change on 5-level paging machine we will have elf binary and
heap mapped above 47-bit by default. This may lead to userspace brakage.
> ---
> arch/x86/include/asm/elf.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h
> index c1a125e47ff3..3a091cea36c5 100644
> --- a/arch/x86/include/asm/elf.h
> +++ b/arch/x86/include/asm/elf.h
> @@ -253,7 +253,7 @@ extern int force_personality32;
> * space open for things that want to use the area for 32-bit pointers.
> */
> #define ELF_ET_DYN_BASE (mmap_is_ia32() ? 0x000400000UL : \
> - (TASK_SIZE / 3 * 2))
> + (DEFAULT_MAP_WINDOW / 3 * 2))
>
> /* This yields a mask that user programs can use to figure out what
> instruction set this CPU supports. This could be done in user space,
> --
> 2.14.2
>
> --
> To unsubscribe, send a message with 'unsubscribe linux-mm' in
> the body to majordomo@kvack.org. For more info on Linux MM,
> see: http://www.linux-mm.org/ .
> Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
--
Kirill A. Shutemov
--
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] x86/mm: Fix ELF_ET_DYN_BASE for 5-level paging
2017-11-07 10:38 [PATCH] x86/mm: Fix ELF_ET_DYN_BASE for 5-level paging Kirill A. Shutemov
2017-11-09 10:38 ` Kirill A. Shutemov
@ 2017-11-09 15:38 ` Michal Hocko
2017-11-09 17:12 ` Thomas Gleixner
2 siblings, 0 replies; 4+ messages in thread
From: Michal Hocko @ 2017-11-09 15:38 UTC (permalink / raw)
To: Kirill A. Shutemov
Cc: Ingo Molnar, Andrew Morton, linux-mm, linux-kernel, Kees Cook,
Ingo Molnar, H. Peter Anvin, Thomas Gleixner, Nicholas Piggin
On Tue 07-11-17 13:38:04, Kirill A. Shutemov wrote:
> On machines with 5-level paging we don't want to allocate mapping above
> 47-bit unless user explicitly asked for it. See b569bab78d8d ("x86/mm:
> Prepare to expose larger address space to userspace") for details.
>
> c715b72c1ba4 ("mm: revert x86_64 and arm64 ELF_ET_DYN_BASE base
> changes") broke the behaviour. After the commit elf binary and heap got
> mapped above 47-bits.
>
> Let's fix this.
>
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> Fixes: c715b72c1ba4 ("mm: revert x86_64 and arm64 ELF_ET_DYN_BASE base changes")
> Cc: Kees Cook <keescook@chromium.org>
> Cc: Ingo Molnar <mingo@elte.hu>
> Cc: "H. Peter Anvin" <hpa@zytor.com>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Nicholas Piggin <npiggin@gmail.com>
FWIW
Acked-by: Michal Hocko <mhocko@suse.com>
> ---
> arch/x86/include/asm/elf.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h
> index c1a125e47ff3..3a091cea36c5 100644
> --- a/arch/x86/include/asm/elf.h
> +++ b/arch/x86/include/asm/elf.h
> @@ -253,7 +253,7 @@ extern int force_personality32;
> * space open for things that want to use the area for 32-bit pointers.
> */
> #define ELF_ET_DYN_BASE (mmap_is_ia32() ? 0x000400000UL : \
> - (TASK_SIZE / 3 * 2))
> + (DEFAULT_MAP_WINDOW / 3 * 2))
>
> /* This yields a mask that user programs can use to figure out what
> instruction set this CPU supports. This could be done in user space,
> --
> 2.14.2
--
Michal Hocko
SUSE Labs
--
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] x86/mm: Fix ELF_ET_DYN_BASE for 5-level paging
2017-11-07 10:38 [PATCH] x86/mm: Fix ELF_ET_DYN_BASE for 5-level paging Kirill A. Shutemov
2017-11-09 10:38 ` Kirill A. Shutemov
2017-11-09 15:38 ` Michal Hocko
@ 2017-11-09 17:12 ` Thomas Gleixner
2 siblings, 0 replies; 4+ messages in thread
From: Thomas Gleixner @ 2017-11-09 17:12 UTC (permalink / raw)
To: Kirill A. Shutemov
Cc: Ingo Molnar, Andrew Morton, linux-mm, linux-kernel, Kees Cook,
Ingo Molnar, H. Peter Anvin, Nicholas Piggin
On Tue, 7 Nov 2017, Kirill A. Shutemov wrote:
> On machines with 5-level paging we don't want to allocate mapping above
> 47-bit unless user explicitly asked for it. See b569bab78d8d ("x86/mm:
> Prepare to expose larger address space to userspace") for details.
>
> c715b72c1ba4 ("mm: revert x86_64 and arm64 ELF_ET_DYN_BASE base
> changes") broke the behaviour. After the commit elf binary and heap got
> mapped above 47-bits.
>
> Let's fix this.
That's a really useless sentence.....
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> Fixes: c715b72c1ba4 ("mm: revert x86_64 and arm64 ELF_ET_DYN_BASE base changes")
> Cc: Kees Cook <keescook@chromium.org>
> Cc: Ingo Molnar <mingo@elte.hu>
> Cc: "H. Peter Anvin" <hpa@zytor.com>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Nicholas Piggin <npiggin@gmail.com>
> ---
> arch/x86/include/asm/elf.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h
> index c1a125e47ff3..3a091cea36c5 100644
> --- a/arch/x86/include/asm/elf.h
> +++ b/arch/x86/include/asm/elf.h
> @@ -253,7 +253,7 @@ extern int force_personality32;
> * space open for things that want to use the area for 32-bit pointers.
> */
> #define ELF_ET_DYN_BASE (mmap_is_ia32() ? 0x000400000UL : \
> - (TASK_SIZE / 3 * 2))
> + (DEFAULT_MAP_WINDOW / 3 * 2))
>
> /* This yields a mask that user programs can use to figure out what
> instruction set this CPU supports. This could be done in user space,
> --
> 2.14.2
>
>
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
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^ permalink raw reply [flat|nested] 4+ messages in thread
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2017-11-07 10:38 [PATCH] x86/mm: Fix ELF_ET_DYN_BASE for 5-level paging Kirill A. Shutemov
2017-11-09 10:38 ` Kirill A. Shutemov
2017-11-09 15:38 ` Michal Hocko
2017-11-09 17:12 ` Thomas Gleixner
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