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

On Tue, Oct 29, 2019 at 10:59:20AM +0800, Baoquan He wrote:
> 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?

Thank you for pinging me and so sorry for the delay.
I'll post the v4 in this week.

Thanks,
Masa

>
> 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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