Re: [PATCH 1/2] x86/mm/KASLR: Fix the wrong calculation of kalsr region initial size
On 09/08/18 at 02:10pm, Thomas Gleixner wrote:
> On Wed, 29 Aug 2018, Baoquan He wrote:
>
> > In memory KASLR, __PHYSICAL_MASK_SHIFT is taken to calculate the
> > initial size of the direct mapping region. This is right in the
> > old code where __PHYSICAL_MASK_SHIFT was equal to MAX_PHYSMEM_BITS,
> > 46bit, and only 4-level mode was supported.
> >
> > Later, in commit:
> > b83ce5ee91471d ("x86/mm/64: Make __PHYSICAL_MASK_SHIFT always 52"),
> > __PHYSICAL_MASK_SHIFT was changed to be 52 always, no matter it's
> > 5-level or 4-level. This is wrong for 4-level paging. Then when
> > adapt phyiscal memory region size based on available memory, it
> > will overflow if the amount of system RAM and the padding is bigger
> > than 64TB.
> >
> > In fact, here MAX_PHYSMEM_BITS should be used instead. Fix it by
> > by replacing __PHYSICAL_MASK_SHIFT with MAX_PHYSMEM_BITS.
> >
> > Signed-off-by: Baoquan He
>
> This lacks a fixes tag .
Sure, I will add fix tag in this patch, and arrange a new patchset
according to discussion with Kirill after test.
Thanks
Baoquan
Re: [PATCH 1/2] x86/mm/KASLR: Fix the wrong calculation of kalsr region initial size
On 09/08/18 at 02:10pm, Thomas Gleixner wrote:
> On Wed, 29 Aug 2018, Baoquan He wrote:
>
> > In memory KASLR, __PHYSICAL_MASK_SHIFT is taken to calculate the
> > initial size of the direct mapping region. This is right in the
> > old code where __PHYSICAL_MASK_SHIFT was equal to MAX_PHYSMEM_BITS,
> > 46bit, and only 4-level mode was supported.
> >
> > Later, in commit:
> > b83ce5ee91471d ("x86/mm/64: Make __PHYSICAL_MASK_SHIFT always 52"),
> > __PHYSICAL_MASK_SHIFT was changed to be 52 always, no matter it's
> > 5-level or 4-level. This is wrong for 4-level paging. Then when
> > adapt phyiscal memory region size based on available memory, it
> > will overflow if the amount of system RAM and the padding is bigger
> > than 64TB.
> >
> > In fact, here MAX_PHYSMEM_BITS should be used instead. Fix it by
> > by replacing __PHYSICAL_MASK_SHIFT with MAX_PHYSMEM_BITS.
> >
> > Signed-off-by: Baoquan He
>
> This lacks a fixes tag .
Sure, I will add fix tag in this patch, and arrange a new patchset
according to discussion with Kirill after test.
Thanks
Baoquan
Re: [PATCH 1/2] x86/mm/KASLR: Fix the wrong calculation of kalsr region initial size
On Wed, 29 Aug 2018, Baoquan He wrote:
> In memory KASLR, __PHYSICAL_MASK_SHIFT is taken to calculate the
> initial size of the direct mapping region. This is right in the
> old code where __PHYSICAL_MASK_SHIFT was equal to MAX_PHYSMEM_BITS,
> 46bit, and only 4-level mode was supported.
>
> Later, in commit:
> b83ce5ee91471d ("x86/mm/64: Make __PHYSICAL_MASK_SHIFT always 52"),
> __PHYSICAL_MASK_SHIFT was changed to be 52 always, no matter it's
> 5-level or 4-level. This is wrong for 4-level paging. Then when
> adapt phyiscal memory region size based on available memory, it
> will overflow if the amount of system RAM and the padding is bigger
> than 64TB.
>
> In fact, here MAX_PHYSMEM_BITS should be used instead. Fix it by
> by replacing __PHYSICAL_MASK_SHIFT with MAX_PHYSMEM_BITS.
>
> Signed-off-by: Baoquan He
This lacks a fixes tag .
Thanks,
tglx
Re: [PATCH 1/2] x86/mm/KASLR: Fix the wrong calculation of kalsr region initial size
On Wed, 29 Aug 2018, Baoquan He wrote:
> In memory KASLR, __PHYSICAL_MASK_SHIFT is taken to calculate the
> initial size of the direct mapping region. This is right in the
> old code where __PHYSICAL_MASK_SHIFT was equal to MAX_PHYSMEM_BITS,
> 46bit, and only 4-level mode was supported.
>
> Later, in commit:
> b83ce5ee91471d ("x86/mm/64: Make __PHYSICAL_MASK_SHIFT always 52"),
> __PHYSICAL_MASK_SHIFT was changed to be 52 always, no matter it's
> 5-level or 4-level. This is wrong for 4-level paging. Then when
> adapt phyiscal memory region size based on available memory, it
> will overflow if the amount of system RAM and the padding is bigger
> than 64TB.
>
> In fact, here MAX_PHYSMEM_BITS should be used instead. Fix it by
> by replacing __PHYSICAL_MASK_SHIFT with MAX_PHYSMEM_BITS.
>
> Signed-off-by: Baoquan He
This lacks a fixes tag .
Thanks,
tglx
Re: [PATCH 1/2] x86/mm/KASLR: Fix the wrong calculation of kalsr region initial size
Thanks Baoquan!
Reviewed-by: Thomas Garnier
On Wed, Aug 29, 2018 at 4:49 AM Kirill A. Shutemov wrote:
>
> On Wed, Aug 29, 2018 at 10:17:53AM +0800, Baoquan He wrote:
> > In memory KASLR, __PHYSICAL_MASK_SHIFT is taken to calculate the
> > initial size of the direct mapping region. This is right in the
> > old code where __PHYSICAL_MASK_SHIFT was equal to MAX_PHYSMEM_BITS,
> > 46bit, and only 4-level mode was supported.
> >
> > Later, in commit:
> > b83ce5ee91471d ("x86/mm/64: Make __PHYSICAL_MASK_SHIFT always 52"),
> > __PHYSICAL_MASK_SHIFT was changed to be 52 always, no matter it's
> > 5-level or 4-level. This is wrong for 4-level paging. Then when
> > adapt phyiscal memory region size based on available memory, it
> > will overflow if the amount of system RAM and the padding is bigger
> > than 64TB.
> >
> > In fact, here MAX_PHYSMEM_BITS should be used instead. Fix it by
> > by replacing __PHYSICAL_MASK_SHIFT with MAX_PHYSMEM_BITS.
> >
> > Signed-off-by: Baoquan He
>
> Acked-by: Kirill A. Shutemov
>
> --
> Kirill A. Shutemov
--
Thomas
Re: [PATCH 1/2] x86/mm/KASLR: Fix the wrong calculation of kalsr region initial size
Thanks Baoquan!
Reviewed-by: Thomas Garnier
On Wed, Aug 29, 2018 at 4:49 AM Kirill A. Shutemov wrote:
>
> On Wed, Aug 29, 2018 at 10:17:53AM +0800, Baoquan He wrote:
> > In memory KASLR, __PHYSICAL_MASK_SHIFT is taken to calculate the
> > initial size of the direct mapping region. This is right in the
> > old code where __PHYSICAL_MASK_SHIFT was equal to MAX_PHYSMEM_BITS,
> > 46bit, and only 4-level mode was supported.
> >
> > Later, in commit:
> > b83ce5ee91471d ("x86/mm/64: Make __PHYSICAL_MASK_SHIFT always 52"),
> > __PHYSICAL_MASK_SHIFT was changed to be 52 always, no matter it's
> > 5-level or 4-level. This is wrong for 4-level paging. Then when
> > adapt phyiscal memory region size based on available memory, it
> > will overflow if the amount of system RAM and the padding is bigger
> > than 64TB.
> >
> > In fact, here MAX_PHYSMEM_BITS should be used instead. Fix it by
> > by replacing __PHYSICAL_MASK_SHIFT with MAX_PHYSMEM_BITS.
> >
> > Signed-off-by: Baoquan He
>
> Acked-by: Kirill A. Shutemov
>
> --
> Kirill A. Shutemov
--
Thomas
Re: [PATCH 1/2] x86/mm/KASLR: Fix the wrong calculation of kalsr region initial size
On Wed, Aug 29, 2018 at 10:17:53AM +0800, Baoquan He wrote:
> In memory KASLR, __PHYSICAL_MASK_SHIFT is taken to calculate the
> initial size of the direct mapping region. This is right in the
> old code where __PHYSICAL_MASK_SHIFT was equal to MAX_PHYSMEM_BITS,
> 46bit, and only 4-level mode was supported.
>
> Later, in commit:
> b83ce5ee91471d ("x86/mm/64: Make __PHYSICAL_MASK_SHIFT always 52"),
> __PHYSICAL_MASK_SHIFT was changed to be 52 always, no matter it's
> 5-level or 4-level. This is wrong for 4-level paging. Then when
> adapt phyiscal memory region size based on available memory, it
> will overflow if the amount of system RAM and the padding is bigger
> than 64TB.
>
> In fact, here MAX_PHYSMEM_BITS should be used instead. Fix it by
> by replacing __PHYSICAL_MASK_SHIFT with MAX_PHYSMEM_BITS.
>
> Signed-off-by: Baoquan He
Acked-by: Kirill A. Shutemov
--
Kirill A. Shutemov
Re: [PATCH 1/2] x86/mm/KASLR: Fix the wrong calculation of kalsr region initial size
On Wed, Aug 29, 2018 at 10:17:53AM +0800, Baoquan He wrote:
> In memory KASLR, __PHYSICAL_MASK_SHIFT is taken to calculate the
> initial size of the direct mapping region. This is right in the
> old code where __PHYSICAL_MASK_SHIFT was equal to MAX_PHYSMEM_BITS,
> 46bit, and only 4-level mode was supported.
>
> Later, in commit:
> b83ce5ee91471d ("x86/mm/64: Make __PHYSICAL_MASK_SHIFT always 52"),
> __PHYSICAL_MASK_SHIFT was changed to be 52 always, no matter it's
> 5-level or 4-level. This is wrong for 4-level paging. Then when
> adapt phyiscal memory region size based on available memory, it
> will overflow if the amount of system RAM and the padding is bigger
> than 64TB.
>
> In fact, here MAX_PHYSMEM_BITS should be used instead. Fix it by
> by replacing __PHYSICAL_MASK_SHIFT with MAX_PHYSMEM_BITS.
>
> Signed-off-by: Baoquan He
Acked-by: Kirill A. Shutemov
--
Kirill A. Shutemov
[PATCH 1/2] x86/mm/KASLR: Fix the wrong calculation of kalsr region initial size
In memory KASLR, __PHYSICAL_MASK_SHIFT is taken to calculate the
initial size of the direct mapping region. This is right in the
old code where __PHYSICAL_MASK_SHIFT was equal to MAX_PHYSMEM_BITS,
46bit, and only 4-level mode was supported.
Later, in commit:
b83ce5ee91471d ("x86/mm/64: Make __PHYSICAL_MASK_SHIFT always 52"),
__PHYSICAL_MASK_SHIFT was changed to be 52 always, no matter it's
5-level or 4-level. This is wrong for 4-level paging. Then when
adapt phyiscal memory region size based on available memory, it
will overflow if the amount of system RAM and the padding is bigger
than 64TB.
In fact, here MAX_PHYSMEM_BITS should be used instead. Fix it by
by replacing __PHYSICAL_MASK_SHIFT with MAX_PHYSMEM_BITS.
Signed-off-by: Baoquan He
---
arch/x86/mm/kaslr.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/mm/kaslr.c b/arch/x86/mm/kaslr.c
index 61db77b0eda9..0988971069c9 100644
--- a/arch/x86/mm/kaslr.c
+++ b/arch/x86/mm/kaslr.c
@@ -93,7 +93,7 @@ void __init kernel_randomize_memory(void)
if (!kaslr_memory_enabled())
return;
- kaslr_regions[0].size_tb = 1 << (__PHYSICAL_MASK_SHIFT - TB_SHIFT);
+ kaslr_regions[0].size_tb = 1 << (MAX_PHYSMEM_BITS - TB_SHIFT);
kaslr_regions[1].size_tb = VMALLOC_SIZE_TB;
/*
--
2.13.6
[PATCH 1/2] x86/mm/KASLR: Fix the wrong calculation of kalsr region initial size
In memory KASLR, __PHYSICAL_MASK_SHIFT is taken to calculate the
initial size of the direct mapping region. This is right in the
old code where __PHYSICAL_MASK_SHIFT was equal to MAX_PHYSMEM_BITS,
46bit, and only 4-level mode was supported.
Later, in commit:
b83ce5ee91471d ("x86/mm/64: Make __PHYSICAL_MASK_SHIFT always 52"),
__PHYSICAL_MASK_SHIFT was changed to be 52 always, no matter it's
5-level or 4-level. This is wrong for 4-level paging. Then when
adapt phyiscal memory region size based on available memory, it
will overflow if the amount of system RAM and the padding is bigger
than 64TB.
In fact, here MAX_PHYSMEM_BITS should be used instead. Fix it by
by replacing __PHYSICAL_MASK_SHIFT with MAX_PHYSMEM_BITS.
Signed-off-by: Baoquan He
---
arch/x86/mm/kaslr.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/mm/kaslr.c b/arch/x86/mm/kaslr.c
index 61db77b0eda9..0988971069c9 100644
--- a/arch/x86/mm/kaslr.c
+++ b/arch/x86/mm/kaslr.c
@@ -93,7 +93,7 @@ void __init kernel_randomize_memory(void)
if (!kaslr_memory_enabled())
return;
- kaslr_regions[0].size_tb = 1 << (__PHYSICAL_MASK_SHIFT - TB_SHIFT);
+ kaslr_regions[0].size_tb = 1 << (MAX_PHYSMEM_BITS - TB_SHIFT);
kaslr_regions[1].size_tb = VMALLOC_SIZE_TB;
/*
--
2.13.6
