* [PATCH] powerpc/32: Fix missing NULL pmd check in virt_to_kpte()
@ 2020-03-07 10:09 Christophe Leroy
2020-03-13 3:35 ` Nathan Chancellor
2020-03-17 13:14 ` Michael Ellerman
0 siblings, 2 replies; 5+ messages in thread
From: Christophe Leroy @ 2020-03-07 10:09 UTC (permalink / raw)
To: Benjamin Herrenschmidt, Paul Mackerras, Michael Ellerman, ndesaulniers
Cc: linux-kernel, linuxppc-dev
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
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH] powerpc/32: Fix missing NULL pmd check in virt_to_kpte()
2020-03-07 10:09 [PATCH] powerpc/32: Fix missing NULL pmd check in virt_to_kpte() Christophe Leroy
@ 2020-03-13 3:35 ` Nathan Chancellor
2020-03-16 22:51 ` Nick Desaulniers
2020-03-17 13:14 ` Michael Ellerman
1 sibling, 1 reply; 5+ messages in thread
From: Nathan Chancellor @ 2020-03-13 3:35 UTC (permalink / raw)
To: Christophe Leroy
Cc: Benjamin Herrenschmidt, Paul Mackerras, Michael Ellerman,
ndesaulniers, linuxppc-dev, linux-kernel
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>
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] powerpc/32: Fix missing NULL pmd check in virt_to_kpte()
2020-03-13 3:35 ` Nathan Chancellor
@ 2020-03-16 22:51 ` Nick Desaulniers
2020-03-16 23:51 ` Michael Ellerman
0 siblings, 1 reply; 5+ messages in thread
From: Nick Desaulniers @ 2020-03-16 22:51 UTC (permalink / raw)
To: Michael Ellerman
Cc: Christophe Leroy, Benjamin Herrenschmidt, Paul Mackerras,
linuxppc-dev, LKML, Nathan Chancellor
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
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] powerpc/32: Fix missing NULL pmd check in virt_to_kpte()
2020-03-16 22:51 ` Nick Desaulniers
@ 2020-03-16 23:51 ` Michael Ellerman
0 siblings, 0 replies; 5+ messages in thread
From: Michael Ellerman @ 2020-03-16 23:51 UTC (permalink / raw)
To: Nick Desaulniers
Cc: Christophe Leroy, Benjamin Herrenschmidt, Paul Mackerras,
linuxppc-dev, LKML, Nathan Chancellor
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
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] powerpc/32: Fix missing NULL pmd check in virt_to_kpte()
2020-03-07 10:09 [PATCH] powerpc/32: Fix missing NULL pmd check in virt_to_kpte() Christophe Leroy
2020-03-13 3:35 ` Nathan Chancellor
@ 2020-03-17 13:14 ` Michael Ellerman
1 sibling, 0 replies; 5+ messages in thread
From: Michael Ellerman @ 2020-03-17 13:14 UTC (permalink / raw)
To: Christophe Leroy, Benjamin Herrenschmidt, Paul Mackerras, ndesaulniers
Cc: linuxppc-dev, linux-kernel
On Sat, 2020-03-07 at 10:09:15 UTC, 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>
Applied to powerpc next, thanks.
https://git.kernel.org/powerpc/c/cc6f0e39000900e5dd1448103a9571f0eccd7d4e
cheers
^ permalink raw reply [flat|nested] 5+ messages in thread
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2020-03-07 10:09 [PATCH] powerpc/32: Fix missing NULL pmd check in virt_to_kpte() Christophe Leroy
2020-03-13 3:35 ` Nathan Chancellor
2020-03-16 22:51 ` Nick Desaulniers
2020-03-16 23:51 ` Michael Ellerman
2020-03-17 13:14 ` Michael Ellerman
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