Re: [PATCH 4.9.257 1/1] futex: Fix OWNER_DEAD fixup

["Zhengyejian (Zetta)" <zhengyejian1@huawei.com>]

On 2021/2/23 21:00, Greg KH wrote:
> On Mon, Feb 22, 2021 at 09:11:43PM +0800, Zhengyejian (Zetta) wrote:
>>
>>
>> On 2021/2/22 20:36, Greg KH wrote:
>>> On Mon, Feb 22, 2021 at 08:20:38PM +0800, Zhengyejian (Zetta) wrote:
>>>>
>>>>
>>>> On 2021/2/22 20:07, Greg KH wrote:
>>>>> On Mon, Feb 22, 2021 at 11:54:24AM +0000, Lee Jones wrote:
>>>>>> On Mon, 22 Feb 2021, Zheng Yejian wrote:
>>>>>>
>>>>>>> From: Peter Zijlstra <peterz@infradead.org>
>>>>>>>
>>>>>>> commit a97cb0e7b3f4c6297fd857055ae8e895f402f501 upstream.
>>>>>>>
>>>>>>> Both Geert and DaveJ reported that the recent futex commit:
>>>>>>>
>>>>>>>      c1e2f0eaf015 ("futex: Avoid violating the 10th rule of futex")
>>>>>>>
>>>>>>> introduced a problem with setting OWNER_DEAD. We set the bit on an
>>>>>>> uninitialized variable and then entirely optimize it away as a
>>>>>>> dead-store.
>>>>>>>
>>>>>>> Move the setting of the bit to where it is more useful.
>>>>>>>
>>>>>>> Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
>>>>>>> Reported-by: Dave Jones <davej@codemonkey.org.uk>
>>>>>>> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
>>>>>>> Cc: Andrew Morton <akpm@linux-foundation.org>
>>>>>>> Cc: Linus Torvalds <torvalds@linux-foundation.org>
>>>>>>> Cc: Paul E. McKenney <paulmck@us.ibm.com>
>>>>>>> Cc: Peter Zijlstra <peterz@infradead.org>
>>>>>>> Cc: Thomas Gleixner <tglx@linutronix.de>
>>>>>>> Fixes: c1e2f0eaf015 ("futex: Avoid violating the 10th rule of futex")
>>>>>>> Link: http://lkml.kernel.org/r/20180122103947.GD2228@hirez.programming.kicks-ass.net
>>>>>>> Signed-off-by: Ingo Molnar <mingo@kernel.org>
>>>>>>> Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>
>>>>>>> ---
>>>>>>>     kernel/futex.c | 7 +++----
>>>>>>>     1 file changed, 3 insertions(+), 4 deletions(-)
>>>>>>
>>>>>> Reviewed-by: Lee Jones <lee.jones@linaro.org>
>>>>>
>>>>> This does not apply to the 4.9.y tree at all right now, are you all sure
>>>>> you got the backport correct?
>>>>>
>>>>> confused,
>>>>>
>>>>> greg k-h
>>>>> .
>>>>>
>>>> I make the patch basing on 282aeb477a10 ("Linux 4.9.257").
>>>> Should I base on f0cf73f13b39 ("Linux 4.9.258-rc1")?
>>>
>>> Yes please as I think this is already there.
>>>
>>> How about just waiting for the next release to come out, I will push out
>>> the 4.4 and 4.9 -rc releases right now as well to give everyone a chance
>>> to sync up properly.
>> Ok, I will rebase this patch then.
> 
> Great, can you try 4.9.258?

I'm very glad to.
Rebased patch is ready:
 
https://lore.kernel.org/lkml/20210223144151.916675-1-zhengyejian1@huawei.com/

Zheng Yejian