Messages in this thread | | | Date | Tue, 6 Dec 2016 18:20:28 +0000 | From | Mark Rutland <> | Subject | Re: [PATCHv4 09/10] mm/usercopy: Switch to using lm_alias |
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On Tue, Nov 29, 2016 at 10:55:28AM -0800, Laura Abbott wrote: > > The usercopy checking code currently calls __va(__pa(...)) to check for > aliases on symbols. Switch to using lm_alias instead. > > Signed-off-by: Laura Abbott <labbott@redhat.com>
I've given this a go on Juno, which boots happily. LKDTM triggers as expected when copying from the kernel text and its alias.
Reviewed-by: Mark Rutland <mark.rutland@arm.com> Tested-by: Mark Rutland <mark.rutland@arm.com>
Thanks, Mark.
> --- > Found when reviewing the kernel. Tested. > --- > mm/usercopy.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/mm/usercopy.c b/mm/usercopy.c > index 3c8da0a..8345299 100644 > --- a/mm/usercopy.c > +++ b/mm/usercopy.c > @@ -108,13 +108,13 @@ static inline const char *check_kernel_text_object(const void *ptr, > * __pa() is not just the reverse of __va(). This can be detected > * and checked: > */ > - textlow_linear = (unsigned long)__va(__pa(textlow)); > + textlow_linear = (unsigned long)lm_alias(textlow); > /* No different mapping: we're done. */ > if (textlow_linear == textlow) > return NULL; > > /* Check the secondary mapping... */ > - texthigh_linear = (unsigned long)__va(__pa(texthigh)); > + texthigh_linear = (unsigned long)lm_alias(texthigh); > if (overlaps(ptr, n, textlow_linear, texthigh_linear)) > return "<linear kernel text>"; > > -- > 2.7.4 >
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