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Sender: Larry Finger <larry.finger@gmail.com>
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Date:   Sat, 13 May 2023 14:55:51 -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>
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 <13262218.uLZWGnKmhe@jernej-laptop>
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From:   Larry Finger <Larry.Finger@lwfinger.net>
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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.

Larry