linux-kernel - Re: [PATCH 1/4] zswap bugfix: memory leaks when re-swapon

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Date:	Sun, 25 Aug 2013 20:00:53 +0800
From:	Weijie Yang <weijie.yang.kh@...il.com>
To:	Seth Jennings <sjenning@...ux.vnet.ibm.com>
Cc:	Minchan Kim <minchan@...nel.org>, Bob Liu <bob.liu@...cle.com>,
	linux-mm@...ck.org, linux-kernel@...r.kernel.org,
	weijie.yang@...sung.com
Subject: Re: [PATCH 1/4] zswap bugfix: memory leaks when re-swapon

2013/8/23 Seth Jennings <sjenning@...ux.vnet.ibm.com>:
> On Fri, Aug 23, 2013 at 07:03:37PM +0800, Weijie Yang wrote:
>> zswap_tree is not freed when swapoff, and it got re-kzalloc in swapon,
>> memory leak occurs.
>> Add check statement in zswap_frontswap_init so that zswap_tree is
>> inited only once.
>>
>> ---
>>  mm/zswap.c |    5 +++++
>>  1 files changed, 5 insertions(+), 0 deletions(-)
>>
>> diff --git a/mm/zswap.c b/mm/zswap.c
>> index deda2b6..1cf1c07 100644
>> --- a/mm/zswap.c
>> +++ b/mm/zswap.c
>> @@ -826,6 +826,11 @@ static void zswap_frontswap_init(unsigned type)
>>  {
>>       struct zswap_tree *tree;
>>
>> +     if (zswap_trees[type]) {
>> +             BUG_ON(zswap_trees[type]->rbroot != RB_ROOT);  /* invalidate_area set it */
>
> Lets leave this BUG_ON() out.  If we want to make sure that the rbtree has
> been properly emptied out, we should do it in
> zswap_frontswap_invalidate_area() after the while loop and make it a
> WARN_ON() since the problem is not fatal.
>
> Seth
>

ok.

>> +             return;
>> +     }
>> +
>>       tree = kzalloc(sizeof(struct zswap_tree), GFP_KERNEL);
>>       if (!tree)
>>               goto err;
>> --
>> 1.7.0.4
>>
>
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