Re: [PATCH 2/3] introduce probe_slab_address()

[Oleg Nesterov]

On 10/28, Oleg Nesterov wrote:
>
> On 10/28, Kirill Tkhai wrote:
> >
> > Yes, probe_kernel_read() is in [1/3], but it's not the same as
> > __probe_kernel_read() for blackfin, for example.
> >
> > It's defined as
> >
> > long __weak probe_kernel_read(void *dst, const void *src, size_t size)
> >     __attribute__((alias("__probe_kernel_read")));
> >
> > But blackfin's probe_kernel_read() redefines this __weak function,
> > isn't it? Didn't get_freepointer_safe() use to call architecture's
> > probe_kernel_read() before?
>
> I _think_ that __probe_kernel_read(slab_ddr) should be fine.
>
> Yes, an architecture may want to reimplement probe_kernel_read() to
> allow to safely access the special areas, or special addresses.
>
> But again, in this case we know that this address points to the
> "normal" kernel memory, __copy_from_user_inatomic() should work fine.

OTOH, perhaps probe_kernel_address() should use probe_kernel_read(), not
__probe_kernel_read(). But currently it just calls __copy_inatomic() so
1/3 follows this logic.

Oleg.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/