x86/mm: Prevent kernel Oops in PTDUMP code with HIGHPTE=y

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commit d6ef1f194b upstream.

The walk_pte_level() function just uses __va to get the virtual address of
the PTE page, but that breaks when the PTE page is not in the direct
mapping with HIGHPTE=y.

The result is an unhandled kernel paging request at some random address
when accessing the current_kernel or current_user file.

Use the correct API to access PTE pages.

Fixes: fe770bf031 ('x86: clean up the page table dumper and add 32-bit support')
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: jgross@suse.com
Cc: JBeulich@suse.com
Cc: hpa@zytor.com
Cc: aryabinin@virtuozzo.com
Cc: kirill.shutemov@linux.intel.com
Link: https://lkml.kernel.org/r/1523971636-4137-1-git-send-email-joro@8bytes.org
[bwh: Backported to 3.16:
 - Keep using pte_pgprot() to get protection flags
 - Adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

...

This commit is contained in:

Joerg Roedel 2018-04-17 15:27:16 +02:00 • committed by Ben Hutchings

parent b117dd4e47

commit 943b7d6653

1 changed files with 6 additions and 4 deletions

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arch/x86/mm/dump_pagetables.c

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