Messages in this thread | | | From | Nick Desaulniers <> | Date | Mon, 16 Mar 2020 15:51:32 -0700 | Subject | Re: [PATCH] powerpc/32: Fix missing NULL pmd check in virt_to_kpte() |
| |
Hello ppc friends, did this get picked up into -next yet?
On Thu, Mar 12, 2020 at 8:35 PM Nathan Chancellor <natechancellor@gmail.com> wrote: > > On Sat, Mar 07, 2020 at 10:09:15AM +0000, Christophe Leroy wrote: > > 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 > > > > With QEMU 4.2.0, I can confirm this fixes the panic: > > Tested-by: Nathan Chancellor <natechancellor@gmail.com>
-- Thanks, ~Nick Desaulniers
| |