Re: futex: Switch to USER_DS for futex test (was: Re: linux-next:manual merge of the akpm-current tree with the tip tree)

[Geert Uytterhoeven]

CC linux-arch

https://lkml.org/lkml/2013/12/11/141

On Tue, Jan 14, 2014 at 5:19 PM, H. Peter Anvin <hpa@xxxxxxxxx> wrote:
> On 01/14/2014 05:17 AM, Geert Uytterhoeven wrote:
>>>
>>> This seems terribly broken, the *futex_value*() ops should not need
>>> that; they are supposed to access userspace without any of that.
>>
>> Why don't they need set_fs(USER_DS)?
>
> Because USER_DS is the normal operating state?  It would appear m68k is

Is it?

> the only(?) arch that calls initcalls with get_fs() == KERNEL_DS...

On ARM:

fs = 0x0, USER_DS = 0xbf000000, KERNEL_DS = 0x0

Presumably also on s390, as the fix for m68k broke s390. That's why it's still
in -mm and not yet in mainline.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
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