Messages in this thread | | | From | Thomas Garnier <> | Date | Mon, 8 Aug 2016 11:00:40 -0700 | Subject | Re: [Resend][PATCH] x86/power/64: Always create temporary identity mapping correctly |
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On Mon, Aug 8, 2016 at 6:54 AM, Rafael J. Wysocki <rafael@kernel.org> wrote: > On Mon, Aug 8, 2016 at 3:40 PM, Borislav Petkov <bp@suse.de> wrote: >> On Mon, Aug 08, 2016 at 03:31:31PM +0200, Rafael J. Wysocki wrote: >>> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com> >>> >>> The low-level resume-from-hibernation code on x86-64 uses >>> kernel_ident_mapping_init() to create the temoprary identity mapping, >>> but that function assumes that the offset between kernel virtual >>> addresses and physical addresses is aligned on the PGD level. >>> >>> However, with a randomized identity mapping base, it may be aligned >>> on the PUD level and if that happens, the temporary identity mapping >>> created by set_up_temporary_mappings() will not reflect the actual >>> kernel identity mapping and the image restoration will fail as a >>> result (leading to a kernel panic most of the time). >>> >>> To fix this problem, rework kernel_ident_mapping_init() to support >>> unaligned offsets between KVA and PA up to the PMD level and make >>> set_up_temporary_mappings() use it as approprtiate. >>> >>> Reported-by: Thomas Garnier <thgarnie@google.com> >> >> Reported-by: Borislav Petkov <bp@suse.de> >> >>> Suggested-by: Yinghai Lu <yinghai@kernel.org> >>> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> >>> Acked-by: Yinghai Lu <yinghai@kernel.org> >>> --- >>> >>> This is sort of urgent, because hibernation doesn't work with KASLR on x86-64 >>> in 4.8-rc1 AFAICS and this should make them work together again. >>> >>> Unless anyone sees any problems with it, I'll queue it up for 4.8-rc2. >>> >>> Thomas, would it be possible to test it with KASLR enabled, please? >>
I tested it on my setup couple times. Worked well.
>> Is that the only patch which needs to be tested? Ontop of which tree? > > That should be the only one on top of plain 4.8-rc1. > > If it doesn't help, we need more work to do. :-) > >> CONFIG_RANDOMIZE_MEMORY blew up s2d on my laptop here so I'll run it >> once I have the required info from you :) > > Thanks! > > Best, > Rafael
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