Messages in this thread | | | Date | Sat, 8 Sep 2018 14:10:46 +0200 (CEST) | From | Thomas Gleixner <> | Subject | Re: [PATCH 1/2] x86/mm/KASLR: Fix the wrong calculation of kalsr region initial size |
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On Wed, 29 Aug 2018, Baoquan He wrote:
> In memory KASLR, __PHYSICAL_MASK_SHIFT is taken to calculate the > initial size of the direct mapping region. This is right in the > old code where __PHYSICAL_MASK_SHIFT was equal to MAX_PHYSMEM_BITS, > 46bit, and only 4-level mode was supported. > > Later, in commit: > b83ce5ee91471d ("x86/mm/64: Make __PHYSICAL_MASK_SHIFT always 52"), > __PHYSICAL_MASK_SHIFT was changed to be 52 always, no matter it's > 5-level or 4-level. This is wrong for 4-level paging. Then when > adapt phyiscal memory region size based on available memory, it > will overflow if the amount of system RAM and the padding is bigger > than 64TB. > > In fact, here MAX_PHYSMEM_BITS should be used instead. Fix it by > by replacing __PHYSICAL_MASK_SHIFT with MAX_PHYSMEM_BITS. > > Signed-off-by: Baoquan He <bhe@redhat.com>
This lacks a fixes tag .....
Thanks,
tglx
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