Messages in this thread | | | Subject | Re: [PATCH 1/2] x86: fix norandmaps | From | Dmitry Safonov <> | Date | Mon, 10 Jul 2017 14:56:00 +0300 |
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On 07/10/2017 02:14 PM, Oleg Nesterov wrote: > Documentation/admin-guide/kernel-parameters.txt says: > > norandmaps Don't use address space randomization. Equivalent > to echo 0 > /proc/sys/kernel/randomize_va_space > > but it doesn't work because arch_rnd() which is used to randomize > mm->mmap_base returns a random value unconditionally. > > Shift the PF_RANDOMIZE check from arch_mmap_rnd() to arch_rnd(). > > Fixes: 1b028f784e8c ("x86/mm: Introduce mmap_compat_base() for 32-bit mmap()") > Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Thanks, Oleg, Reviewed-by: Dmitry Safonov <dsafonov@virtuozzo.com>
> --- > arch/x86/mm/mmap.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/mm/mmap.c b/arch/x86/mm/mmap.c > index 19ad095..6369d04 100644 > --- a/arch/x86/mm/mmap.c > +++ b/arch/x86/mm/mmap.c > @@ -82,13 +82,13 @@ static int mmap_is_legacy(void) > > static unsigned long arch_rnd(unsigned int rndbits) > { > + if (!(current->flags & PF_RANDOMIZE)) > + return 0; > return (get_random_long() & ((1UL << rndbits) - 1)) << PAGE_SHIFT; > } > > unsigned long arch_mmap_rnd(void) > { > - if (!(current->flags & PF_RANDOMIZE)) > - return 0; > return arch_rnd(mmap_is_ia32() ? mmap32_rnd_bits : mmap64_rnd_bits); > } > >
-- Dmitry
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