mt7921: Oops in mt76_dma_rx_fill

mt7921: Oops in mt76_dma_rx_fill

[Michael Büsch]

Hi,

on the latest stable 5.16.8 (df659ebe) the Mediatek WLAN driver crashes
on my machine in a DMA function.

Please excuse me for the crappy photos. The first one has been captured
out of a video. Therefore it's partially interleaved with the
predecessor frame.

https://bues.ch/misc/mt7921/mt7921_oops1.jpg
https://bues.ch/misc/mt7921/mt7921_oops2.jpg

Most of the time the crash happens right during system boot.

The stable kernel 5.15.y does not crash. (However, I frequently get
connection interruptions. But I'm not sure whether that's related to
the driver.)

03:00.0 Network controller: MEDIATEK Corp. MT7921 802.11ax PCI Express Wireless Network Adapter

03:00.0 0280: 14c3:7961
        Subsystem: 17aa:e0bc
        Physical Slot: 0
        Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx+
        Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
        Latency: 0, Cache Line Size: 32 bytes
        Interrupt: pin A routed to IRQ 94
        IOMMU group: 11
        Region 0: Memory at 670200000 (64-bit, prefetchable) [size=1M]
        Region 2: Memory at 670300000 (64-bit, prefetchable) [size=16K]
        Region 4: Memory at 670304000 (64-bit, prefetchable) [size=4K]
        Capabilities: <access denied>
        Kernel driver in use: mt7921e
        Kernel modules: mt7921e


-- 
Michael Büsch
https://bues.ch/

Re: mt7921: Oops in mt76_dma_rx_fill

[Michael Büsch]

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Does anybody have an idea why this driver crashes?

I tried to bisect it. But that turns out to be very hard as the
intermediate versions are all very unstable, too. For various reasons.
Therefore, I aborted my bisect attempt.

But if you have an idea what patch I could try, I'd be very happy to
do so.

-- 
Michael Büsch
https://bues.ch/


On Wed, 9 Feb 2022 17:05:50 +0100
Michael Büsch <m@bues.ch> wrote:

> Hi,
> 
> on the latest stable 5.16.8 (df659ebe) the Mediatek WLAN driver
> crashes on my machine in a DMA function.
> 
> Please excuse me for the crappy photos. The first one has been
> captured out of a video. Therefore it's partially interleaved with the
> predecessor frame.
> 
> https://bues.ch/misc/mt7921/mt7921_oops1.jpg
> https://bues.ch/misc/mt7921/mt7921_oops2.jpg
> 
> Most of the time the crash happens right during system boot.
> 
> The stable kernel 5.15.y does not crash. (However, I frequently get
> connection interruptions. But I'm not sure whether that's related to
> the driver.)
> 
> 03:00.0 Network controller: MEDIATEK Corp. MT7921 802.11ax PCI
> Express Wireless Network Adapter
> 
> 03:00.0 0280: 14c3:7961
>         Subsystem: 17aa:e0bc
>         Physical Slot: 0
>         Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop-
> ParErr- Stepping- SERR- FastB2B- DisINTx+ Status: Cap+ 66MHz- UDF-
> FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR-
> INTx- Latency: 0, Cache Line Size: 32 bytes Interrupt: pin A routed
> to IRQ 94 IOMMU group: 11
>         Region 0: Memory at 670200000 (64-bit, prefetchable) [size=1M]
>         Region 2: Memory at 670300000 (64-bit, prefetchable)
> [size=16K] Region 4: Memory at 670304000 (64-bit, prefetchable)
> [size=4K] Capabilities: <access denied>
>         Kernel driver in use: mt7921e
>         Kernel modules: mt7921e
> 
> 



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