Re: [PATCH 3/3] x86/mm: disable ioremap free page handling on x86-PAE

[Kani, Toshi]

On Mon, 2018-04-30 at 11:59 -0600, Toshi Kani wrote:
> ioremap() supports pmd mappings on x86-PAE.  However, kernel's pmd
> tables are not shared among processes on x86-PAE.  Therefore, any
> update to sync'd pmd entries need re-syncing.  Freeing a pte page
> also leads to a vmalloc fault and hits the BUG_ON in vmalloc_sync_one().
> 
> Disable free page handling on x86-PAE.  pud_free_pmd_page() and
> pmd_free_pte_page() simply return 0 if a given pud/pmd entry is present.
> This assures that ioremap() does not update sync'd pmd entries at the
> cost of falling back to pte mappings.
> 
> Fixes: 28ee90fe6048 ("x86/mm: implement free pmd/pte page interfaces")
> Reported-by: Joerg Roedel <joro@xxxxxxxxxx>

Hi Joerg,

Does it solve your problem?  Let me know if you have any issue with the
series. 

Thanks,
-Toshi