[PATCH] x86/mm: fix dump pagetables for 4 levels of page tables

[PATCH] x86/mm: fix dump pagetables for 4 levels of page tables

[Juergen Gross]

Commit fdd3d8ce0ea62 ("x86/dump_pagetables: Add support for 5-level
paging") introduced an error for dumping with only 4 levels by setting
PGD_LEVEL_MULT to a wrong value.

This is leading to e.g. addresses printed as "(null)" for ranges:

x86/mm: Found insecure W+X mapping at address (null)/(null)

Signed-off-by: Juergen Gross <jgross@suse.com>
---
 arch/x86/mm/dump_pagetables.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/mm/dump_pagetables.c b/arch/x86/mm/dump_pagetables.c
index 9f305be71a72..bce6990b1d81 100644
--- a/arch/x86/mm/dump_pagetables.c
+++ b/arch/x86/mm/dump_pagetables.c
@@ -111,7 +111,7 @@ static struct addr_marker address_markers[] = {
 #define PMD_LEVEL_MULT (PTRS_PER_PTE * PTE_LEVEL_MULT)
 #define PUD_LEVEL_MULT (PTRS_PER_PMD * PMD_LEVEL_MULT)
 #define P4D_LEVEL_MULT (PTRS_PER_PUD * PUD_LEVEL_MULT)
-#define PGD_LEVEL_MULT (PTRS_PER_PUD * P4D_LEVEL_MULT)
+#define PGD_LEVEL_MULT (PTRS_PER_P4D * P4D_LEVEL_MULT)
 
 #define pt_dump_seq_printf(m, to_dmesg, fmt, args...)		\
 ({								\
-- 
2.12.0

Re: [PATCH] x86/mm: fix dump pagetables for 4 levels of page tables

[Kirill A. Shutemov]

On Wed, Apr 12, 2017 at 04:36:34PM +0200, Juergen Gross wrote:
> Commit fdd3d8ce0ea62 ("x86/dump_pagetables: Add support for 5-level
> paging") introduced an error for dumping with only 4 levels by setting
> PGD_LEVEL_MULT to a wrong value.
> 
> This is leading to e.g. addresses printed as "(null)" for ranges:
> 
> x86/mm: Found insecure W+X mapping at address (null)/(null)
> 
> Signed-off-by: Juergen Gross <jgross@suse.com>

Sorry for this.

Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>

-- 
 Kirill A. Shutemov

[tip:x86/mm] x86/mm: Fix dump pagetables for 4 levels of page tables

[tip-bot for Juergen Gross]

Commit-ID:  84bbabc3a452e8085cfbd745ff0bff2b89074417
Gitweb:     http://git.kernel.org/tip/84bbabc3a452e8085cfbd745ff0bff2b89074417
Author:     Juergen Gross <jgross@suse.com>
AuthorDate: Wed, 12 Apr 2017 16:36:34 +0200
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Thu, 13 Apr 2017 00:26:30 +0200

x86/mm: Fix dump pagetables for 4 levels of page tables

Commit fdd3d8ce0ea62 ("x86/dump_pagetables: Add support for 5-level
paging") introduced an error for dumping with only 4 levels by setting
PGD_LEVEL_MULT to a wrong value.

This is leading to e.g. addresses printed as "(null)" for ranges:

  x86/mm: Found insecure W+X mapping at address (null)/(null)

Make PGD_LEVEL_MULT a multiple of PTRS_PER_P4D instead of PTRS_PER_PUD

Fixes: fdd3d8ce0ea62 ("x86/dump_pagetables: Add support for 5-level paging")
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Link: http://lkml.kernel.org/r/20170412143634.6846-1-jgross@suse.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

---
 arch/x86/mm/dump_pagetables.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/mm/dump_pagetables.c b/arch/x86/mm/dump_pagetables.c
index 9f305be..bce6990 100644
--- a/arch/x86/mm/dump_pagetables.c
+++ b/arch/x86/mm/dump_pagetables.c
@@ -111,7 +111,7 @@ static struct addr_marker address_markers[] = {
 #define PMD_LEVEL_MULT (PTRS_PER_PTE * PTE_LEVEL_MULT)
 #define PUD_LEVEL_MULT (PTRS_PER_PMD * PMD_LEVEL_MULT)
 #define P4D_LEVEL_MULT (PTRS_PER_PUD * PUD_LEVEL_MULT)
-#define PGD_LEVEL_MULT (PTRS_PER_PUD * P4D_LEVEL_MULT)
+#define PGD_LEVEL_MULT (PTRS_PER_P4D * P4D_LEVEL_MULT)
 
 #define pt_dump_seq_printf(m, to_dmesg, fmt, args...)		\
 ({								\