On Mon, May 31, 2021 at 5:49 PM Greg Kroah-Hartman
<gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
>
> On Mon, May 31, 2021 at 05:33:02PM +0300, Andy Shevchenko wrote:
> > Hi!
> >
> > The only patch that made v5.13-rc4 effectively broke USB on Intel Merrifield.
> >
> > My reproducer:
> > 1. Boot with switch in gadget mode
> > 2. Enable USB ethernet
> > 3. Switch to host
> > 4. wait a bit for device enumeration, etc
> > 5. Switch back
> > 6. No gadget mode, kernel RCU stall detected (USB become unusable, so
> > does the system)
> >
> > [ 115.792620] rcu: INFO: rcu_sched self-detected stall on CPU
> > [ 115.798410] rcu: 0-....: (24089 ticks this GP)
> > idle=886/1/0x4000000000000000 softirq=3796/3797 fqs=5240
> > [ 115.808333] (t=21000 jiffies g=6505 q=12158)
> > [ 115.812847] NMI backtrace for cpu 0
> > [ 115.816472] CPU: 0 PID: 23 Comm: kworker/0:1 Not tainted 5.13.0-rc4+ #213
> > ...
> >
> > [ 115.977913] add_dma_entry+0xd4/0x1d0
> > [ 115.981760] dma_map_page_attrs+0xd8/0x220
> > [ 115.986063] usb_hcd_map_urb_for_dma+0x3b6/0x4f0
> > [ 115.990895] usb_hcd_submit_urb+0x98/0xbf0
> > [ 115.995263] dln2_rx+0x1ae/0x280 [dln2]
> > ...
> >
> > 100% Reproducibility, revert of the 25dda9fc56bd ("usb: dwc3: gadget:
> > Properly track pending and queued SG") fixes the issue.
> >
> > Please, fix it properly or revert. Thanks!
>
> Care to send the revert?
Sure, But I want to give Thinh a chance to react to this, maybe it
would be a better idea.
Let's say if nothing happens I will send it on Wednesday.
--
With Best Regards,
Andy Shevchenko
