On Tue, Jan 14, 2014 at 1:51 PM, Peter Zijlstra <peterz@xxxxxxxxxxxxx> 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@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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