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From: Ferruh Yigit <ferruh.yigit@amd.com>
To: Gagandeep Singh <G.Singh@nxp.com>, "dev@dpdk.org" <dev@dpdk.org>
Cc: "stable@dpdk.org" <stable@dpdk.org>
Subject: Re: [PATCH 15/15] net/dpaa: fix buffer free in slow path
Date: Thu, 6 Oct 2022 10:42:29 +0100	[thread overview]
Message-ID: <3a635d69-ce9c-3240-ee3b-dccd6b3d0880@amd.com> (raw)
In-Reply-To: <AS8PR04MB8198E001E84B09DDF350190FE15C9@AS8PR04MB8198.eurprd04.prod.outlook.com>

On 10/6/2022 9:51 AM, Gagandeep Singh wrote:
> Hi,
> 
>> -----Original Message-----
>> From: Ferruh Yigit <ferruh.yigit@amd.com>
>> Sent: Wednesday, October 5, 2022 7:52 PM
>> To: Gagandeep Singh <G.Singh@nxp.com>; dev@dpdk.org
>> Cc: stable@dpdk.org
>> Subject: Re: [PATCH 15/15] net/dpaa: fix buffer free in slow path
>>
>> On 9/28/2022 6:25 AM, Gagandeep Singh wrote:
>>> Adding a check in slow path to free those buffers which are not
>>> external.
>>>
>>
>> Can you please explain what was the error before fix, what was happening
>> when you try to free all mbufs?
>>
>> Also it seems previous logic was different, with 'prev_seg' etc, can you
>> explain what/why changed there?
>>
> Actually, there were two issues, this function was converting all the segments present in HW frame
> descriptor to mbuf SG list by doing while on segments in FD (HW descriptor) and in the end
> it frees only one segment by calling the API rte_pktmbuf_free_seg(), so for other segments
> memory will be leaked.
> 

ack

> Now in this change, doing the loop on each segment in FD and if the segment has a valid
> buffer pool id (HW pool id), freeing that segment in the loop itself without converting to a mbuf list.
> if we free all the buffers even those with invalid HW bpid (which will only be the external buffer case),
> then there can be double free because all the external buffer free handling is being done by the
> Xmit function.
> 

Got it, can you please give more information in the commit log as above, 
and can you please elaborate impact of possible double free, will it 
crash etc?

>>> Fixes: 9124e65dd3eb ("net/dpaa: enable Tx queue taildrop")
>>> Cc: stable@dpdk.org
>>>
>>> Signed-off-by: Gagandeep Singh <g.singh@nxp.com>
>>> ---
>>>    drivers/net/dpaa/dpaa_rxtx.c | 23 ++++++++---------------
>>>    1 file changed, 8 insertions(+), 15 deletions(-)
>>>
>>> diff --git a/drivers/net/dpaa/dpaa_rxtx.c
>>> b/drivers/net/dpaa/dpaa_rxtx.c index 4d285b4f38..ce4f3d6c85 100644
>>> --- a/drivers/net/dpaa/dpaa_rxtx.c
>>> +++ b/drivers/net/dpaa/dpaa_rxtx.c
>>> @@ -455,7 +455,7 @@ dpaa_free_mbuf(const struct qm_fd *fd)
>>>    	bp_info = DPAA_BPID_TO_POOL_INFO(fd->bpid);
>>>    	format = (fd->opaque & DPAA_FD_FORMAT_MASK) >>
>> DPAA_FD_FORMAT_SHIFT;
>>>    	if (unlikely(format == qm_fd_sg)) {
>>> -		struct rte_mbuf *first_seg, *prev_seg, *cur_seg, *temp;
>>> +		struct rte_mbuf *first_seg, *cur_seg;
>>>    		struct qm_sg_entry *sgt, *sg_temp;
>>>    		void *vaddr, *sg_vaddr;
>>>    		int i = 0;
>>> @@ -469,32 +469,25 @@ dpaa_free_mbuf(const struct qm_fd *fd)
>>>    		sgt = vaddr + fd_offset;
>>>    		sg_temp = &sgt[i++];
>>>    		hw_sg_to_cpu(sg_temp);
>>> -		temp = (struct rte_mbuf *)
>>> -			((char *)vaddr - bp_info->meta_data_size);
>>>    		sg_vaddr = DPAA_MEMPOOL_PTOV(bp_info,
>>>
>> 	qm_sg_entry_get64(sg_temp));
>>> -
>>>    		first_seg = (struct rte_mbuf *)((char *)sg_vaddr -
>>>    						bp_info->meta_data_size);
>>>    		first_seg->nb_segs = 1;
>>> -		prev_seg = first_seg;
>>>    		while (i < DPAA_SGT_MAX_ENTRIES) {
>>>    			sg_temp = &sgt[i++];
>>>    			hw_sg_to_cpu(sg_temp);
>>> -			sg_vaddr = DPAA_MEMPOOL_PTOV(bp_info,
>>> +			if (sg_temp->bpid != 0xFF) {
>>> +				bp_info =
>> DPAA_BPID_TO_POOL_INFO(sg_temp->bpid);
>>> +				sg_vaddr = DPAA_MEMPOOL_PTOV(bp_info,
>>>
>> 	qm_sg_entry_get64(sg_temp));
>>> -			cur_seg = (struct rte_mbuf *)((char *)sg_vaddr -
>>> +				cur_seg = (struct rte_mbuf *)((char
>> *)sg_vaddr -
>>>    						      bp_info-
>>> meta_data_size);
>>> -			first_seg->nb_segs += 1;
>>> -			prev_seg->next = cur_seg;
>>> -			if (sg_temp->final) {
>>> -				cur_seg->next = NULL;
>>> -				break;
>>> +				rte_pktmbuf_free_seg(cur_seg);
>>>    			}
>>> -			prev_seg = cur_seg;
>>> +			if (sg_temp->final)
>>> +				break;
>>>    		}
>>> -
>>> -		rte_pktmbuf_free_seg(temp);
>>>    		rte_pktmbuf_free_seg(first_seg);
>>>    		return 0;
>>>    	}
> 


  reply	other threads:[~2022-10-06  9:42 UTC|newest]

Thread overview: 52+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-28  5:25 [PATCH 00/15] DPAA and DPAA2 driver changes Gagandeep Singh
2022-09-28  5:25 ` [PATCH 01/15] bus/dpaa: use non-block mode for FD open Gagandeep Singh
2022-09-28  5:25 ` [PATCH 02/15] net/enetfec: fix restart issue Gagandeep Singh
2022-09-28  5:25 ` [PATCH 03/15] net/enetfec: fix buffer leak issue Gagandeep Singh
2022-09-28  5:25 ` [PATCH 04/15] net/dpaa2: fix dpdmux configuration for error behaviour Gagandeep Singh
2022-09-28  5:25 ` [PATCH 05/15] net/dpaa2: check free enqueue descriptors before Tx Gagandeep Singh
2022-10-05 14:30   ` Ferruh Yigit
2022-09-28  5:25 ` [PATCH 06/15] net/dpaa: support ESP packet type in packet parsing Gagandeep Singh
2022-10-05 14:20   ` Ferruh Yigit
2022-10-06  8:48     ` Gagandeep Singh
2022-09-28  5:25 ` [PATCH 07/15] net/dpaa2: use internal mempool for SG table Gagandeep Singh
2022-10-05 14:20   ` Ferruh Yigit
2022-10-06  8:49     ` Gagandeep Singh
2022-10-06  9:38       ` Ferruh Yigit
2022-10-06 11:18         ` Gagandeep Singh
2022-09-28  5:25 ` [PATCH 08/15] net/dpaa2: fix buffer free on transmit SG packets Gagandeep Singh
2022-10-06  7:48   ` Ferruh Yigit
2022-09-28  5:25 ` [PATCH 09/15] bus/fslmc: add timeout in MC send command API Gagandeep Singh
2022-09-28  5:25 ` [PATCH 10/15] net/dpaa: fix Jumbo packet Rx in case of VSP Gagandeep Singh
2022-09-28  5:25 ` [PATCH 11/15] bus/dpaa: pass interface name as a string instead of pointer Gagandeep Singh
2022-10-05 14:21   ` Ferruh Yigit
2022-10-06  8:51     ` Gagandeep Singh
2022-10-06  9:39       ` Ferruh Yigit
2022-10-06 11:18         ` Gagandeep Singh
2022-09-28  5:25 ` [PATCH 12/15] net/dpaa: use internal mempool for SG table Gagandeep Singh
2022-09-28  5:25 ` [PATCH 13/15] bus/dpaa: mempool ops registration change Gagandeep Singh
2022-09-28  5:25 ` [PATCH 14/15] net/dpaa: fix buffer free on transmit SG packets Gagandeep Singh
2022-09-28  5:25 ` [PATCH 15/15] net/dpaa: fix buffer free in slow path Gagandeep Singh
2022-10-05 14:21   ` Ferruh Yigit
2022-10-06  8:51     ` Gagandeep Singh
2022-10-06  9:42       ` Ferruh Yigit [this message]
2022-10-06 11:19         ` Gagandeep Singh
2022-10-05 14:27 ` [PATCH 00/15] DPAA and DPAA2 driver changes Ferruh Yigit
2022-10-06 11:15 ` Hemant Agrawal
2022-10-07  3:27 ` [PATCH v2 00/16] " Gagandeep Singh
2022-10-07  3:27   ` [PATCH v2 01/16] bus/dpaa: use non-block mode for FD open Gagandeep Singh
2022-10-07  3:27   ` [PATCH v2 02/16] net/enetfec: fix restart issue Gagandeep Singh
2022-10-07  3:27   ` [PATCH v2 03/16] net/enetfec: fix buffer leak issue Gagandeep Singh
2022-10-07  3:27   ` [PATCH v2 04/16] net/dpaa2: fix dpdmux configuration for error behaviour Gagandeep Singh
2022-10-07  3:27   ` [PATCH v2 05/16] net/dpaa2: check free enqueue descriptors before Tx Gagandeep Singh
2022-10-07  3:27   ` [PATCH v2 06/16] net/dpaa: support ESP packet type in packet parsing Gagandeep Singh
2022-10-07  3:27   ` [PATCH v2 07/16] net/dpaa2: use internal mempool for SG table Gagandeep Singh
2022-10-07  3:27   ` [PATCH v2 08/16] net/dpaa2: fix buffer free on transmit SG packets Gagandeep Singh
2022-10-07  3:27   ` [PATCH v2 09/16] bus/fslmc: add timeout in MC send command API Gagandeep Singh
2022-10-07  3:27   ` [PATCH v2 10/16] net/dpaa: fix Jumbo packet Rx in case of VSP Gagandeep Singh
2022-10-07  3:27   ` [PATCH v2 11/16] doc: add kernel version compatible information Gagandeep Singh
2022-10-07  3:27   ` [PATCH v2 12/16] bus/dpaa: pass interface name as a string instead of pointer Gagandeep Singh
2022-10-07  3:27   ` [PATCH v2 13/16] net/dpaa: use internal mempool for SG table Gagandeep Singh
2022-10-07  3:27   ` [PATCH v2 14/16] bus/dpaa: mempool ops registration change Gagandeep Singh
2022-10-07  3:27   ` [PATCH v2 15/16] net/dpaa: fix buffer free on transmit SG packets Gagandeep Singh
2022-10-07  3:27   ` [PATCH v2 16/16] net/dpaa: fix buffer free in slow path Gagandeep Singh
2022-10-07 15:22   ` [PATCH v2 00/16] DPAA and DPAA2 driver changes Ferruh Yigit

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