linux-kernel - Re: [PATCH] crypto/async_pq: use __free_page() instead of put

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Message-ID: <CAAmzW4Nq8LiFGzyR4YjG8OPev-Pj1dUad+Bus2puSAk_tUcCsA@mail.gmail.com>
Date:	Tue, 1 Mar 2016 22:54:50 +0900
From:	Joonsoo Kim <js1304@...il.com>
To:	Dan Williams <dan.j.williams@...el.com>
Cc:	Arnd Bergmann <arnd@...db.de>,
	Joonsoo Kim <iamjoonsoo.kim@....com>,
	Linux MM <linux-mm@...ck.org>,
	Herbert Xu <herbert@...dor.apana.org.au>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	Michal Nazarewicz <mina86@...a86.com>,
	Steven Rostedt <rostedt@...dmis.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	"David S. Miller" <davem@...emloft.net>,
	NeilBrown <neilb@...e.com>,
	Markus Stockhausen <stockhausen@...logia.de>,
	Vinod Koul <vinod.koul@...el.com>,
	linux-crypto@...r.kernel.org,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] crypto/async_pq: use __free_page() instead of put_page()

2016-03-01 3:04 GMT+09:00 Dan Williams <dan.j.williams@...el.com>:
> On Mon, Feb 29, 2016 at 1:33 AM, Arnd Bergmann <arnd@...db.de> wrote:
>> The addition of tracepoints to the page reference tracking had an
>> unfortunate side-effect in at least one driver that calls put_page
>> from its exit function, resulting in a link error:
>>
>> `.exit.text' referenced in section `__jump_table' of crypto/built-in.o: defined in discarded section `.exit.text' of crypto/built-in.o
>>
>> From a cursory look at that this driver, it seems that it may be
>> doing the wrong thing here anyway, as the page gets allocated
>> using 'alloc_page()', and should be freed using '__free_page()'
>> rather than 'put_page()'.
>>
>> With this patch, I no longer get any other build errors from the
>> page_ref patch, so hopefully we can assume that it's always wrong
>> to call any of those functions from __exit code, and that no other
>> driver does it.
>>
>> Fixes: 0f80830dd044 ("mm/page_ref: add tracepoint to track down page reference manipulation")
>> Signed-off-by: Arnd Bergmann <arnd@...db.de>
>
> Acked-by: Dan Williams <dan.j.williams@...el.com>
>
> Vinod, will you take this one?

Problematic patch ("mm/page_ref: ~~~") is not yet merged one. It is on mmotm
and this fix should go together with it or before it. I think that
handling this fix by
Andrew is easier to all.

Thanks.