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From: Vlastimil Babka <vbabka@suse.cz>
To: "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
	Ajay Kaher <akaher@vmware.com>
Cc: "torvalds@linux-foundation.org" <torvalds@linux-foundation.org>,
	"punit.agrawal@arm.com" <punit.agrawal@arm.com>,
	"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
	"kirill.shutemov@linux.intel.com"
	<kirill.shutemov@linux.intel.com>,
	"willy@infradead.org" <willy@infradead.org>,
	"will.deacon@arm.com" <will.deacon@arm.com>,
	"mszeredi@redhat.com" <mszeredi@redhat.com>,
	"stable@vger.kernel.org" <stable@vger.kernel.org>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Srivatsa Bhat <srivatsab@vmware.com>,
	"srivatsa@csail.mit.edu" <srivatsa@csail.mit.edu>,
	Alexey Makhalov <amakhalov@vmware.com>,
	Srinidhi Rao <srinidhir@vmware.com>,
	Vikash Bansal <bvikas@vmware.com>,
	Anish Swaminathan <anishs@vmware.com>,
	Vasavi Sirnapalli <vsirnapalli@vmware.com>,
	Steven Rostedt <srostedt@vmware.com>,
	"stable@kernel.org" <stable@kernel.org>,
	Ben Hutchings <ben@decadent.org.uk>
Subject: Re: [PATCH v2 6/8] mm: prevent get_user_pages() from overflowing page refcount
Date: Fri, 29 Nov 2019 10:08:57 +0100
Message-ID: <aa13c6b2-fd12-5b0f-b81a-3315ed5b9e95@suse.cz> (raw)
In-Reply-To: <20191121203823.GE813260@kroah.com>

On 11/21/19 9:38 PM, gregkh@linuxfoundation.org wrote:
> On Mon, Nov 11, 2019 at 05:00:29AM +0000, Ajay Kaher wrote:
>>
>> On 06/11/19, 2:25 PM, "Vlastimil Babka" <vbabka@suse.cz> wrote:
>>
>>> On 10/25/19 8:18 AM, Ajay Kaher wrote:
>>>> On 17/10/19, 9:58 PM, "Ajay Kaher" <akaher@vmware.com> wrote:
>>>>     
>>>>>    
>>>>> Could we handle arch-specific gup.c in different patch sets and 
>>>>> let these patches to merge to 4.4.y?
>>>>   
>>>> Vlastimil, please suggest if it's fine to merge these patches to 4.4.y
>>>
>>> I'm not sure if it makes much sense to merge them without the arch-specific gup
>>> support, when we're aware that it's missing.
>>>
>>>> and handle arch-specific gup.c in different patch sets starts from 4.19.y,
>>>
>>> Actually arch-specific gup.c were removed in 4.13, so it's enough to start from
>>> 4.9.y, which I'm going to finally look into.
>>
>> Yes x86 gup.c is removed. s390 gup.c is present till 4.19,
>> so if you are making changes in this file for 4.4.y and 4.9.y, 
>> then same should be done for 4.14.y and v4.19.y.
> 
> Ok, I have no idea what to do here.  I have two different series from
> both of you, yet they are different.
> 
> Can you both come up with a series you agree on, and send it to me, with
> both of your acks so that I know this is what should be applied?  I've
> deleted both of your current series from my todo mbox.

I started by fixing up [1] 4.9, 4.14 and 4.19 which already got the
backport, but without arch-specific gup.c variants. I'll wait for Ajay's
feedback for the 4.4 series.

[1] https://lore.kernel.org/linux-mm/20191129090351.3507-1-vbabka@suse.cz/

> thanks,
> 
> greg k-h
> 


  reply index

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-09  0:44 [PATCH v2 0/8] Backported fixes for 4.4 stable tree Ajay Kaher
2019-10-09  0:44 ` [PATCH v2 1/8] mm: make page ref count overflow check tighter and more explicit Ajay Kaher
2019-10-09  0:44 ` [PATCH v2 2/8] mm: add 'try_get_page()' helper function Ajay Kaher
2019-10-09  0:44 ` [PATCH v2 3/8] mm: handle PTE-mapped tail pages in gerneric fast gup implementaiton Ajay Kaher
2019-10-09  0:44 ` [PATCH v2 4/8] mm, gup: remove broken VM_BUG_ON_PAGE compound check for hugepages Ajay Kaher
2019-10-09  0:44 ` [PATCH v2 5/8] mm, gup: ensure real head page is ref-counted when using hugepages Ajay Kaher
2019-10-09  0:44 ` [PATCH v2 6/8] mm: prevent get_user_pages() from overflowing page refcount Ajay Kaher
2019-10-09 13:13   ` Vlastimil Babka
2019-10-17 16:28     ` Ajay Kaher
2019-10-25  6:18       ` Ajay Kaher
2019-11-06  8:55         ` Vlastimil Babka
2019-11-11  5:00           ` Ajay Kaher
2019-11-21 20:38             ` gregkh
2019-11-29  9:08               ` Vlastimil Babka [this message]
2019-10-09  0:44 ` [PATCH v2 7/8] pipe: add pipe_buf_get() helper Ajay Kaher
2019-10-09  0:44 ` [PATCH v2 8/8] fs: prevent page refcount overflow in pipe_buf_get Ajay Kaher

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