[lkml]   [2018]   [Aug]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH 1/2] x86/mm/KASLR: Fix the wrong calculation of kalsr region initial size
On Wed, Aug 29, 2018 at 10:17:53AM +0800, 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
> Signed-off-by: Baoquan He <>

Acked-by: Kirill A. Shutemov <>

Kirill A. Shutemov

 \ /
  Last update: 2018-08-29 13:50    [W:0.074 / U:2.864 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site