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| Started by | Michael Ellerman <mpe@ellerman.id.au> |
|---|---|
| First post | 2017-01-31 10:20 +0100 |
| Last post | 2017-02-06 04:00 +0100 |
| Articles | 2 — 2 participants |
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Re: [PATCH] powerpc/mm: fix a hardcode on memory boundary checking Michael Ellerman <mpe@ellerman.id.au> - 2017-01-31 10:20 +0100
Re: [PATCH] powerpc/mm: fix a hardcode on memory boundary checking Rui Teng <rui.teng@linux.vnet.ibm.com> - 2017-02-06 04:00 +0100
| From | Michael Ellerman <mpe@ellerman.id.au> |
|---|---|
| Date | 2017-01-31 10:20 +0100 |
| Subject | Re: [PATCH] powerpc/mm: fix a hardcode on memory boundary checking |
| Message-ID | <t5CLw-7mj-15@gated-at.bofh.it> |
Rui Teng <rui.teng@linux.vnet.ibm.com> writes:
> The offset of hugepage block will not be 16G, if the expected
> page is more than one. Calculate the totol size instead of the
> hardcode value.
I assume you found this by code inspection and not by triggering an
actual bug?
cheers
> diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
> index 8033493..b829f8e 100644
> --- a/arch/powerpc/mm/hash_utils_64.c
> +++ b/arch/powerpc/mm/hash_utils_64.c
> @@ -506,7 +506,7 @@ static int __init htab_dt_scan_hugepage_blocks(unsigned long node,
> printk(KERN_INFO "Huge page(16GB) memory: "
> "addr = 0x%lX size = 0x%lX pages = %d\n",
> phys_addr, block_size, expected_pages);
> - if (phys_addr + (16 * GB) <= memblock_end_of_DRAM()) {
> + if (phys_addr + block_size * expected_pages <= memblock_end_of_DRAM()) {
> memblock_reserve(phys_addr, block_size * expected_pages);
> add_gpage(phys_addr, block_size, expected_pages);
> }
> --
> 2.9.0
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| From | Rui Teng <rui.teng@linux.vnet.ibm.com> |
|---|---|
| Date | 2017-02-06 04:00 +0100 |
| Message-ID | <t7HH3-7jE-11@gated-at.bofh.it> |
| In reply to | #1570502 |
On 31/01/2017 5:11 PM, Michael Ellerman wrote:
> Rui Teng <rui.teng@linux.vnet.ibm.com> writes:
>
>> The offset of hugepage block will not be 16G, if the expected
>> page is more than one. Calculate the totol size instead of the
>> hardcode value.
>
> I assume you found this by code inspection and not by triggering an
> actual bug?
Yes, I found this problem only by code inspection. We were finding the
ways to enable 16G huge page besides changing the device tree. For
example, provide a new interface to set these size and pages parameters.
So that I think it may cause problem here.
>
> cheers
>
>> diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
>> index 8033493..b829f8e 100644
>> --- a/arch/powerpc/mm/hash_utils_64.c
>> +++ b/arch/powerpc/mm/hash_utils_64.c
>> @@ -506,7 +506,7 @@ static int __init htab_dt_scan_hugepage_blocks(unsigned long node,
>> printk(KERN_INFO "Huge page(16GB) memory: "
>> "addr = 0x%lX size = 0x%lX pages = %d\n",
>> phys_addr, block_size, expected_pages);
>> - if (phys_addr + (16 * GB) <= memblock_end_of_DRAM()) {
>> + if (phys_addr + block_size * expected_pages <= memblock_end_of_DRAM()) {
>> memblock_reserve(phys_addr, block_size * expected_pages);
>> add_gpage(phys_addr, block_size, expected_pages);
>> }
>> --
>> 2.9.0
>
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