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Re: Fix hppa/ia64/microblaze executable stack default (bug 22156)
On Fri, 22 Sep 2017, John David Anglin wrote:
> On 2017-09-22, at 4:11 PM, Joseph Myers wrote:
>
> > Given what Andreas said at
> > <https://gcc.gnu.org/ml/gcc-patches/2017-09/msg01220.html>, does this mean
> > there are other causes of executable stacks in the kernel, such as
> > VM_STACK_DEFAULT_FLAGS? If so, maybe hppa and microblaze do in fact need
> > the GCC patch rather than the glibc one?
>
> VM_STACK_DEFAULT_FLAGS defaults to VM_DATA_DEFAULT_FLAGS when it is
> not defined, and it is not defined on hppa.
>
> On hppa, VM_DATA_DEFAULT_FLAGS, and it is:
>
> #define VM_DATA_DEFAULT_FLAGS (VM_READ | VM_WRITE | VM_EXEC | \
> VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)
Given this, and your experiment showing the stack is indeed executable on
hppa, are the hppa parts of the GCC patch OK? (I think we've established
that ia64 should use the glibc change. Based on VM_DATA_DEFAULT_FLAGS,
microblaze would use the GCC change but hopefully there will be more
information from microblaze people soon.)
--
Joseph S. Myers
joseph@codesourcery.com