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SubjectRe: [PATCH v3 0/5] Adjust the padding size for KASLR
Hi Masa,

On 08/30/19 at 05:47pm, Masayoshi Mizuma wrote:
> From: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>

Any plan about this patchset?

Thanks
Baoquan

>
> The system sometimes crashes while memory hot-adding on KASLR
> enabled system. The crash happens because the regions pointed by
> kaslr_regions[].base are overwritten by the hot-added memory.
>
> It happens because of the padding size for kaslr_regions[].base isn't
> enough for the system whose physical memory layout has huge space for
> memory hotplug. kaslr_regions[].base points "actual installed
> memory size + padding" or higher address. So, if the "actual + padding"
> is lower address than the maximum memory address, which means the memory
> address reachable by memory hot-add, kaslr_regions[].base is destroyed by
> the overwritten.
>
> address
> ^
> |------- maximum memory address (Hotplug)
> | ^
> |------- kaslr_regions[0].base | Hotadd-able region
> | ^ |
> | | padding |
> | V V
> |------- actual memory address (Installed on boot)
> |
>
> Fix it by getting the maximum memory address from SRAT and store
> the value in boot_param, then set the padding size while KASLR
> initializing if the default padding size isn't enough.
>
> Masayoshi Mizuma (5):
> x86/boot: Wrap up the SRAT traversing code into subtable_parse()
> x86/boot: Add max_addr field in struct boot_params
> x86/boot: Get the max address from SRAT
> x86/mm/KASLR: Cleanup calculation for direct mapping size
> x86/mm/KASLR: Adjust the padding size for the direct mapping.
>
> Documentation/x86/zero-page.rst | 4 ++
> arch/x86/boot/compressed/acpi.c | 33 +++++++++---
> arch/x86/include/uapi/asm/bootparam.h | 2 +-
> arch/x86/mm/kaslr.c | 77 +++++++++++++++++++++------
> 4 files changed, 93 insertions(+), 23 deletions(-)
>
> --
> 2.18.1
>

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