Messages in this thread | | | From | Michael Ellerman <> | Subject | Re: [PATCH] powerpc/32: Fix missing NULL pmd check in virt_to_kpte() | Date | Tue, 17 Mar 2020 10:51:55 +1100 |
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Nick Desaulniers <ndesaulniers@google.com> writes: > Hello ppc friends, did this get picked up into -next yet?
Not yet.
It's in my next-test, but it got stuck there because some subsequent patches caused some CI errors that I had to debug.
I'll push it to next today.
cheers
> 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
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