The page table dump code doesn't know about huge pages, so currently
it crashes (or walks random memory, usually leading to a crash), if it
finds a huge page. On Book3S we only see huge pages in the Linux page
tables when we're using the P9 Radix MMU.
Teaching the code to properly handle huge pages is a bit more involved,
so for now just prevent the crash.
Cc: sta...@vger.kernel.org # v4.10+
Fixes: 8eb07b187000 ("powerpc/mm: Dump linux pagetables")
Signed-off-by: Michael Ellerman <m...@ellerman.id.au>
---
arch/powerpc/mm/dump_linuxpagetables.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/mm/dump_linuxpagetables.c
b/arch/powerpc/mm/dump_linuxpagetables.c
index d659345a98d6..6070d3d60ef1 100644
--- a/arch/powerpc/mm/dump_linuxpagetables.c
+++ b/arch/powerpc/mm/dump_linuxpagetables.c
@@ -391,7 +391,7 @@ static void walk_pmd(struct pg_state *st, pud_t *pud,
unsigned long start)
for (i = 0; i < PTRS_PER_PMD; i++, pmd++) {
addr = start + i * PMD_SIZE;
- if (!pmd_none(*pmd))
+ if (!pmd_none(*pmd) && !pmd_huge(*pmd))
/* pmd exists */
walk_pte(st, pmd, addr);
else
@@ -407,7 +407,7 @@ static void walk_pud(struct pg_state *st, pgd_t *pgd,
unsigned long start)
for (i = 0; i < PTRS_PER_PUD; i++, pud++) {
addr = start + i * PUD_SIZE;
- if (!pud_none(*pud))
+ if (!pud_none(*pud) && !pud_huge(*pud))
/* pud exists */
walk_pmd(st, pud, addr);
else
@@ -427,7 +427,7 @@ static void walk_pagetables(struct pg_state *st)
*/
for (i = 0; i < PTRS_PER_PGD; i++, pgd++) {
addr = KERN_VIRT_START + i * PGDIR_SIZE;
- if (!pgd_none(*pgd))
+ if (!pgd_none(*pgd) && !pgd_huge(*pgd))
/* pgd exists */
walk_pud(st, pgd, addr);
else
--
2.7.4
