Re: inconsistent lock state with usbnet/asix usb ethernet and xhci

[Marek Szyprowski]

Hi Oliver,

On 2018-02-27 11:37, Oliver Neukum wrote:
> Am Dienstag, den 27.02.2018, 08:26 +0100 schrieb Marek Szyprowski:
>
> > I've noticed that USBnet/ASIX AX88772B USB driver produces deplock kernel
> > warning ("inconsistent lock state") on Chromebook2 Peach-PIT board. No
> Is that 32 bit?

Yes. ARM 32bit. Exynos5420 SoC (4 x CortexA15 + 4 x CortexA7 big.LITTLE 
CPUs).

> > special activity is needed to reproduce this issue, it happens almost
> > on every boot. ASIX USB ethernet is connected to XHCI USB host controller
> > on that board. Is it a known issue? Frankly I have no idea where to look
> No, it is not known.
>
> > to fix it. The same adapter connected to EHCI ports on other boards based
> > on the same SoC works fine without any warnings.
> Odd.
>
> > And the log with mentioned warning:
> >
> > [ÂÂ 17.768040] ================================
> > [ÂÂ 17.772239] WARNING: inconsistent lock state
> > [ÂÂ 17.776511] 4.16.0-rc3-next-20180227-00007-g876c53a7493c #453 Not tainted
> > [ÂÂ 17.783329] --------------------------------
> > [ÂÂ 17.787580] inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage.
> > [ÂÂ 17.793607] swapper/0/0 [HC0[0]:SC1[1]:HE1:SE0] takes:
> > [ÂÂ 17.798751]Â (&syncp->seq#5){?.-.}, at: [<9b22e5f0>]
> > asix_rx_fixup_internal+0x188/0x288
> Looks like this triggers (in usbnet):
>
>  Â Â Â Â u64_stats_update_begin(&stats64->syncp);
>  ÂÂÂÂÂÂÂÂstats64->rx_packets++;
>  ÂÂÂÂÂÂÂÂstats64->rx_bytes += skb->len;
>  ÂÂÂÂÂÂÂÂu64_stats_update_end(&stats64->syncp);
>
> That I considered to be called under lock.
> Could you comment this out for testing?

Yes, commenting this out indeed hides the deplock warning.

Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland