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Commit d6ef1f19 authored by Joerg Roedel's avatar Joerg Roedel Committed by Thomas Gleixner
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x86/mm: Prevent kernel Oops in PTDUMP code with HIGHPTE=y 



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: fe770bf0 ('x86: clean up the page table dumper and add 32-bit support')
Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
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
parent 1340ccfa

arch/x86/mm/dump_pagetables.c

+6 −5
Original line number Original line Diff line number Diff line
@@ -18,6 +18,7 @@ 
#include <linux/init.h>

#include <linux/init.h>

#include <linux/sched.h>

#include <linux/sched.h>

#include <linux/seq_file.h>

#include <linux/seq_file.h>

#include <linux/highmem.h>





#include <asm/pgtable.h>

#include <asm/pgtable.h>
@@ -334,16 +335,16 @@ static void walk_pte_level(struct seq_file *m, struct pg_state *st, pmd_t addr, 
			   pgprotval_t eff_in, unsigned long P)

			   pgprotval_t eff_in, unsigned long P)

{

{

	int i;

	int i;

	pte_t *start;

	pte_t *pte;

	pgprotval_t prot, eff;

	pgprotval_t prot, eff;





	start = (pte_t *)pmd_page_vaddr(addr);

	for (i = 0; i < PTRS_PER_PTE; i++) {

	for (i = 0; i < PTRS_PER_PTE; i++) {

		prot = pte_flags(*start);

		eff = effective_prot(eff_in, prot);

		st->current_address = normalize_addr(P + i * PTE_LEVEL_MULT);

		st->current_address = normalize_addr(P + i * PTE_LEVEL_MULT);

		pte = pte_offset_map(&addr, st->current_address);

		prot = pte_flags(*pte);

		eff = effective_prot(eff_in, prot);

		note_page(m, st, __pgprot(prot), eff, 5);

		note_page(m, st, __pgprot(prot), eff, 5);

		start++;

		pte_unmap(pte);

	}

	}

}

}

#ifdef CONFIG_KASAN

#ifdef CONFIG_KASAN