Messages in this thread | | | From | Masayoshi Mizuma <> | Subject | [PATCH v4 0/4] Adjust the padding size for KASLR | Date | Fri, 1 Nov 2019 21:09:07 -0400 |
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From: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
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 (4): 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: Adjust the padding size for the direct mapping.
Documentation/x86/zero-page.rst | 4 ++ arch/x86/boot/compressed/acpi.c | 35 ++++++++++++--- arch/x86/include/uapi/asm/bootparam.h | 2 +- arch/x86/mm/kaslr.c | 65 ++++++++++++++++++++------- 4 files changed, 83 insertions(+), 23 deletions(-)
-- 2.20.1
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