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

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Date:	Mon, 29 Feb 2016 10:04:38 -0800
From:	Dan Williams <dan.j.williams@...el.com>
To:	Arnd Bergmann <arnd@...db.de>
Cc:	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()

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?