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

From: Weijie Yang
Date: Sun Aug 25 2013 - 08:01:00 EST


2013/8/23 Seth Jennings <sjenning@xxxxxxxxxxxxxxxxxx>:
> 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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