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Sender: Larry Finger <larry.finger@gmail.com>
Message-ID: <fc20e35c-c7e6-cfa5-bdc5-f88ceee12f71@lwfinger.net>
Date:   Sat, 13 May 2023 16:21:47 -0500
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Subject: Re: Driver for rtw8723ds
To:     =?UTF-8?Q?Jernej_=c5=a0krabec?= <jernej.skrabec@gmail.com>,
        Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Cc:     linux-wireless <linux-wireless@vger.kernel.org>
References: <72a8eeb1-c91c-80a7-5a09-1b7963e0996b@lwfinger.net>
 <13262218.uLZWGnKmhe@jernej-laptop>
 <f3368bf9-c6e6-f418-41da-b9de185acd34@lwfinger.net>
 <21872829.EfDdHjke4D@jernej-laptop>
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From:   Larry Finger <Larry.Finger@lwfinger.net>
In-Reply-To: <21872829.EfDdHjke4D@jernej-laptop>
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On 5/13/23 15:13, Jernej Škrabec wrote:
> Dne sobota, 13. maj 2023 ob 21:55:51 CEST je Larry Finger napisal(a):
>> On 5/13/23 05:23, Jernej Škrabec wrote:
>>> Larry,
>>>
>>> Dne sreda, 10. maj 2023 ob 23:47:24 CEST je Larry Finger napisal(a):
>>>> On 5/10/23 16:07, Martin Blumenstingl wrote:
>>>>> On Wed, May 10, 2023 at 12:02 AM Larry Finger <Larry.Finger@lwfinger.net> wrote:
>>>>> [...]
>>>>>> I added that patch to the driver. The user reports that he was able to do a ping
>>>>>> and an nslookup before it crashed with the following in the log:
>>>>> That's some positive news alongside the crash log: it seems that a
>>>>> part of the driver works! :-)
>>>>>
>>>>>> [    8.700626] skbuff: skb_over_panic: text:ffff8000011924ac len:3341 put:3341
>>>>>> head:ffff000003b3c000 data:ffff000003b3c040 tail:0xd4d end:0x2c0 dev:<NULL>
>>>>> [...]
>>>>>> Somehow skb->tail was greater than skb->end. Unfortunately I do not have access
>>>>>> to gdb to tell you what line corresponds to rtw_sdio_rx_skb+0x50 on the MangoPi
>>>>>> MQ Quad.
>>>>> I need to have a closer look at the pkg_offset and struct
>>>>> rtw_rx_pkt_stat which we receive.
>>>>> Recently my own MangoPI MQ-Quad arrived but I did not have the time to
>>>>> set it up yet. I'll try to do so during the weekend so I can debug
>>>>> this on my own.
>>>>>
>>>>> Please ping me next week in case I haven't provided any update until then.
>>>>
>>>> I have some test prints in to check for skb overrun. My initial indication is
>>>> that the problem was in the c2h branch of rtw_sdio_rx_skb(), but my next run
>>>> should verify that. My changes will do a pr_warn_once() when the problem
>>>> happens, and then drop the skb.
>>>>
>>>> My contact reported that he had one run of 3 minutes before the problem
>>>> happened, which is good news for most of the driver.
>>>
>>> I may have discovered something interesting. rtl8723ds vendor driver has
>>> following checks in RX data parsing code:
>>> https://github.com/lwfinger/rtl8723ds/blob/master/hal/rtl8723d/sdio/rtl8723ds_recv.c#L83-L99
>>>
>>> Those checks are absent in rtl8822bs vendor driver, which was my original
>>> development platform for SDIO. This may indicate some kind of bug in FW
>>> and/or HW.
>>>
>>> I think that at least second check, which checks for exactly the case your
>>> client experience, can be easily added and tested.
>>
>> Thanks for this update. I added the following to the start of rtw_sdio_rx_skb():
>>          /* fix Hardware RX data error, drop whole recv_buffer */
>>          if (!(rtwdev->hal.rcr & BIT_ACRC32) && pkt_stat->crc_err) {
>>                  kfree_skb(skb);
>>                  return;
>>          }
>> I think that duplicates the code in the vendor driver.
>>
>> I have not heard from my user as to whether it helps. My communications with him
>> are at https://github.com/lwfinger/rtl8723ds/issues/37.
> 
> I had second part in mind (see attachment), but this is IMO only sanity check
> and it will mask the issue. At this point I'm not sure if this is something that
> can happen occasionally or is there additional bug in rtw88 code. I'll check
> rtl8723ds c2h code in greater detail.
> 
> In any case, I would argue that all 3 patches in this thread are valid and
> should be submitted upstream.

That patch looks good. I ill apply it to my rtw88 repo.

Larry