linux-kernel - Re: linux-next: manual merge of the akpm-current tree with the tip tree

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Date:	Tue, 14 Jan 2014 14:17:55 +0100
From:	Geert Uytterhoeven <geert@...ux-m68k.org>
To:	Peter Zijlstra <peterz@...radead.org>
Cc:	Stephen Rothwell <sfr@...b.auug.org.au>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...e.hu>, "H. Peter Anvin" <hpa@...or.com>,
	Linux-Next <linux-next@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Davidlohr Bueso <davidlohr@...com>
Subject: Re: linux-next: manual merge of the akpm-current tree with the tip tree

On Tue, Jan 14, 2014 at 1:51 PM, Peter Zijlstra <peterz@...radead.org> wrote:
> On Tue, Jan 14, 2014 at 03:53:31PM +1100, Stephen Rothwell wrote:
>> Today's linux-next merge of the akpm-current tree got a conflict in
>> kernel/futex.c between commit a52b89ebb6d4 ("futexes: Increase hash table
>> size for better performance") from the tip tree and commit 61beee6c76e5
>> ("futex: switch to USER_DS for futex test") from the akpm-current tree.
>>
>> @@@ -2869,10 -2748,13 +2871,13 @@@
>>        * implementation, the non-functional ones will return
>>        * -ENOSYS.
>>        */
>> +     fs = get_fs();
>> +     set_fs(USER_DS);
>>       if (cmpxchg_futex_value_locked(&curval, NULL, 0, 0) == -EFAULT)
>>               futex_cmpxchg_enabled = 1;
>> +     set_fs(fs);
>>
>
> 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)?

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

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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