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From: Arnd Bergmann <arnd@arndb.de>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Mel Gorman <mgorman@techsingularity.net>,
	Michal Hocko <mhocko@suse.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Joonsoo Kim <iamjoonsoo.kim@lge.com>,
	linux-mm@kvack.org,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] mm: ensure alloc_flags in slow path are initialized
Date: Mon, 23 Jan 2017 17:02:34 +0100	[thread overview]
Message-ID: <CAK8P3a29aAA-YCkk=2h3iW=KTW=kq=gSniWfCzZs4nmpa8Adfw@mail.gmail.com> (raw)
In-Reply-To: <ffce0866-0233-c7c4-027a-a0a1caa26cf3@suse.cz>

On Mon, Jan 23, 2017 at 1:55 PM, Vlastimil Babka <vbabka@suse.cz> wrote:
> On 01/23/2017 01:16 PM, Arnd Bergmann wrote:

>> To be honest, I can't figure that out either, maybe it is or
>> maybe not,
>
>
> Seems the report is correct and not false positive, in scenario when we goto
> nopage before the assignment, and then goto retry because of __GFP_NOFAIL.

Ok, thanks for checking!

>> but moving the existing initialization up a little
>> higher looks safe and makes it obvious to both me and gcc that
>> the initialization comes before the first use.
>>
>> Fixes: 74eaa4a97e8e ("mm: consolidate GFP_NOFAIL checks in the allocator
>> slowpath")
>
>
> That's a non-stable -next commit ID for mmotm patch:
> mm-consolidate-gfp_nofail-checks-in-the-allocator-slowpath.patch
>
> The patch itself was OK, the problem only comes from integration with
> another mmotm patch (also independently OK):
> mm-page_alloc-fix-premature-oom-when-racing-with-cpuset-mems-update.patch
>
> By their ordering in mmotm, it would work to treat this as a fix for the
> GFP_NOFAIL patch, possibly merged into it.

Ok. I only tracked down which commit introduced the warning, which was
the one above.

    Arnd

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  reply	other threads:[~2017-01-23 16:02 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-01-23 12:16 Arnd Bergmann
2017-01-23 12:55 ` Vlastimil Babka
2017-01-23 16:02   ` Arnd Bergmann [this message]
2017-01-23 22:54 ` David Rientjes
2017-01-23 23:56 ` Andrew Morton
2017-01-24  9:19   ` Vlastimil Babka

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