Re: [PATCH] net: hns3: destroy the page pool if RX buffer allocation fails

[Jijie Shao <shaojijie@huawei.com>]

on 2026/11/7 2:03, Simon Horman wrote:
> On Tue, Nov 03, 2026 at 10:05:33AM +0000, Wentao Liang wrote:
>> hns3_alloc_ring_memory() creates the page pool and then fills the RX
>> ring with buffers from it. If filling the ring fails, the error path
>> only frees the descriptors and the descriptor callbacks, so the page
>> pool created a moment earlier is leaked.
>>
>> The page pool is normally destroyed by hns3_fini_ring(), but
>> hns3_init_all_ring() only cleans up the rings that were set up before
>> the failing one, so the pool of the failing ring is never released.
>>
>> Destroy the page pool on the buffer allocation failure path too.
>>
>> Fixes: 93188e9642c3 ("net: hns3: support skb's frag page recycling based on page pool")
>> Cc: stable@vger.kernel.org
>> Assisted-by: DeepSeek-V4.1-Flash and OpenAI Codex
>> Signed-off-by: Wentao Liang <vulab@iscas.ac.cn>
>> ---
>>   drivers/net/ethernet/hisilicon/hns3/hns3_enet.c | 4 ++++
>>   1 file changed, 4 insertions(+)
>>
>> diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
>> index 47788be64be6..fe339ddc6379 100644
>> --- a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
>> +++ b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
>> @@ -5073,6 +5073,10 @@ static int hns3_alloc_ring_memory(struct hns3_enet_ring *ring)
>>   
>>   out_with_desc:
>>   	hns3_free_desc(ring);
>> +	if (ring->page_pool) {
>> +		page_pool_destroy(ring->page_pool);
>> +		ring->page_pool = NULL;
>> +	}
> The condition is not necessary as as page_pool_destroy is a no-op when
> passed NULL. Please remove it to simplify the code-flow.

Hi Simon, Wentao,

Agreed, good catch. I am fixing the same leak in my series:
   https://lore.kernel.org/all/20261030095633.377289-3-shaojijie@huawei.com/

My v3 had the same redundant guard, and v4 will drop it, since
page_pool_destroy() already handles NULL and out_with_desc is only
reachable from the RX branch.

Wentao, thanks for your work on this and for tracking down the
duplicate. Sorry you had to withdraw it.

Thanks,
Jijie Shao