On Mon, Dec 18, 2017 at 12:42:16PM +0100, Thomas Gleixner wrote:
> From: Thomas Gleixner <t...@linutronix.de>
>
> The check for a present page in printk_prot():
>
> if (!pgprot_val(prot)) {
> /* Not present */
>
> is bogus. If a PTE is set to PAGE_NONE then the pgprot_val is not zero and
> the entry is decoded in bogus ways, e.g. as RX GLB. That is confusing when
> analyzing mapping correctness. Check for the present bit to make an
> informed decision.
>
> Signed-off-by: Thomas Gleixner <t...@linutronix.de>
> ---
> arch/x86/mm/dump_pagetables.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> --- a/arch/x86/mm/dump_pagetables.c
> +++ b/arch/x86/mm/dump_pagetables.c
> @@ -140,7 +140,7 @@ static void printk_prot(struct seq_file
> static const char * const level_name[] =
> { "cr3", "pgd", "p4d", "pud", "pmd", "pte" };
>
> - if (!pgprot_val(prot)) {
> + if (!(pgprot_val(prot) & _PAGE_PRESENT)) {
Just a minor thing: there's a local pr variable a couple of lines up
which is pgprot_val(prot). So you could do additionally:
diff --git a/arch/x86/mm/dump_pagetables.c b/arch/x86/mm/dump_pagetables.c
index dd8820e5da28..1014cfb21c2c 100644
--- a/arch/x86/mm/dump_pagetables.c
+++ b/arch/x86/mm/dump_pagetables.c
@@ -140,7 +140,7 @@ static void printk_prot(struct seq_file *m, pgprot_t prot,
int level, bool dmsg)
static const char * const level_name[] =
{ "cr3", "pgd", "p4d", "pud", "pmd", "pte" };
- if (!(pgprot_val(prot) & _PAGE_PRESENT)) {
+ if (!(pr & _PAGE_PRESENT)) {
/* Not present */
pt_dump_cont_printf(m, dmsg, " ");
} else {
--
Regardless,
Reviewed-by: Borislav Petkov <b...@suse.de>
--
Regards/Gruss,
Boris.
SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284
(AG Nürnberg)
--
