linux-kernel - Re: [PATCH v2 7/8] mm/zsmalloc: add __init,_

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Date:	Wed, 6 Jul 2016 14:21:20 +0800
From:	Ganesh Mahendran <opensource.ganesh@...il.com>
To:	Minchan Kim <minchan@...nel.org>
Cc:	Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>,
	linux-kernel <linux-kernel@...r.kernel.org>,
	Linux-MM <linux-mm@...ck.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Nitin Gupta <ngupta@...are.org>, rostedt@...dmis.org,
	mingo@...hat.com
Subject: Re: [PATCH v2 7/8] mm/zsmalloc: add __init,__exit attribute

2016-07-06 10:48 GMT+08:00 Minchan Kim <minchan@...nel.org>:
> On Tue, Jul 05, 2016 at 10:00:28AM +0900, Sergey Senozhatsky wrote:
>> Hello Ganesh,
>>
>> On (07/04/16 17:21), Ganesh Mahendran wrote:
>> > > On (07/04/16 14:49), Ganesh Mahendran wrote:
>> > > [..]
>> > >> -static void zs_unregister_cpu_notifier(void)
>> > >> +static void __exit zs_unregister_cpu_notifier(void)
>> > >>  {
>> > >
>> > > this __exit symbol is called from `__init zs_init()' and thus is
>> > > free to crash.
>> >
>> > I change code to force the code goto notifier_fail where the
>> > zs_unregister_cpu_notifier will be called.
>> > I tested with zsmalloc module buildin and built as a module.
>>
>> sorry, not sure I understand what do you mean by this.
>
> It seems he tested it both builtin and module with simulating to fail
> zs_register_cpu_notifier so that finally called zs_unergister_cpu_notifier.
> With that, he cannot find any problem.

Yes, This is what I mean.

>>
>
>>
>> > Please correct me, if I miss something.
>>
>> you have an __exit section function being called from
>> __init section:
>>
>> static void __exit zs_unregister_cpu_notifier(void)
>> {
>> }
>>
>> static int __init zs_init(void)
>> {
>>       zs_unregister_cpu_notifier();
>> }
>>
>> it's no good.
>
> Agree.
>
> I didn't look at linker script how to handle it. Although it works well,
> it would be not desirable to mark __exit to the function we already
> know it would be called from non-exit functions.

I will revert change in this patch.
Thanks.