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Subject[PATCH] powerpc/32: Fix missing NULL pmd check in virt_to_kpte()
Date
Commit 2efc7c085f05 ("powerpc/32: drop get_pteptr()"),
replaced get_pteptr() by virt_to_kpte(). But virt_to_kpte() lacks a
NULL pmd check and returns an invalid non NULL pointer when there
is no page table.

Reported-by: Nick Desaulniers <ndesaulniers@google.com>
Fixes: 2efc7c085f05 ("powerpc/32: drop get_pteptr()")
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
arch/powerpc/include/asm/pgtable.h | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/include/asm/pgtable.h b/arch/powerpc/include/asm/pgtable.h
index b80bfd41828d..b1f1d5339735 100644
--- a/arch/powerpc/include/asm/pgtable.h
+++ b/arch/powerpc/include/asm/pgtable.h
@@ -54,7 +54,9 @@ static inline pmd_t *pmd_ptr_k(unsigned long va)

static inline pte_t *virt_to_kpte(unsigned long vaddr)
{
- return pte_offset_kernel(pmd_ptr_k(vaddr), vaddr);
+ pmd_t *pmd = pmd_ptr_k(vaddr);
+
+ return pmd_none(*pmd) ? NULL : pte_offset_kernel(pmd, vaddr);
}
#endif

--
2.25.0
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