On Fri, Jul 23, 2021 at 08:39:26AM +0000, Guido Kiener wrote:
> > From: Qiang.zhang>
> > rcu: INFO: rcu_preempt self-detected stall on CPU
> > rcu: 1-...!: (2 ticks this GP) idle=d92/1/0x4000000000000000
> > softirq=25390/25392 fqs=3
> > (t=12164 jiffies g=31645 q=43226)
> > rcu: rcu_preempt kthread starved for 12162 jiffies! g31645 f0x0
> > RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
> > rcu: Unless rcu_preempt kthread gets sufficient CPU time,
> > OOM is now expected behavior.
> > rcu: RCU grace-period kthread stack dump:
> > task:rcu_preempt state:R running task
> > ...........
> > usbtmc 3-1:0.0: unknown status received: -71 usbtmc 3-1:0.0: unknown status
> > received: -71 usbtmc 3-1:0.0: unknown status received: -71 usbtmc 3-1:0.0:
> > unknown status received: -71 usbtmc 3-1:0.0: unknown status received: -71 usbtmc
> > 3-1:0.0: unknown status received: -71 usbtmc 3-1:0.0: unknown status received: -71
> > usbtmc 3-1:0.0: unknown status received: -71 usbtmc 3-1:0.0: usb_submit_urb
> > failed: -19
> >
> > The function usbtmc_interrupt() resubmits urbs when the error status of an urb is -
> > EPROTO. In systems using the dummy_hcd usb controller this can result in endless
> > interrupt loops when the usbtmc device is disconnected from the host system.
> >
> > Since host controller drivers already try to recover from transmission errors, there is
> > no need to resubmit the urb or try other solutions to repair the error situation.
> >
> > In case of errors the INT pipe just stops to wait for further packets.
> >
> > Fixes: dbf3e7f654c0 ("Implement an ioctl to support the USMTMC-USB488
> > READ_STATUS_BYTE operation")
> > Cc: stable@xxxxxxxxxxxxxxx
> > Reported-by: syzbot+e2eae5639e7203360018@xxxxxxxxxxxxxxxxxxxxxxxxx
> > Signed-off-by: Qiang.zhang <qiang.zhang@xxxxxxxxxxxxx>
> > ---
> > v1->v2:
> > Add fixes and stable tags, modify description information.
> >
> > drivers/usb/class/usbtmc.c | 9 +--------
> > 1 file changed, 1 insertion(+), 8 deletions(-)
> >
> > diff --git a/drivers/usb/class/usbtmc.c b/drivers/usb/class/usbtmc.c index
> > 74d5a9c5238a..73f419adce61 100644
> > --- a/drivers/usb/class/usbtmc.c
> > +++ b/drivers/usb/class/usbtmc.c
> > @@ -2324,17 +2324,10 @@ static void usbtmc_interrupt(struct urb *urb)
> > dev_err(dev, "overflow with length %d, actual length is %d\n",
> > data->iin_wMaxPacketSize, urb->actual_length);
> > fallthrough;
> > - case -ECONNRESET:
> > - case -ENOENT:
> > - case -ESHUTDOWN:
> > - case -EILSEQ:
> > - case -ETIME:
> > - case -EPIPE:
> > + default:
> > /* urb terminated, clean up */
> > dev_dbg(dev, "urb terminated, status: %d\n", status);
> > return;
> > - default:
> > - dev_err(dev, "unknown status received: %d\n", status);
> > }
> > exit:
> > rv = usb_submit_urb(urb, GFP_ATOMIC);
> > --
> > 2.25.1
>
> The patch looks good to me and is tested on my machine.
>
> Ack-by: Guido Kiener <guido.kiener@xxxxxxxxxxxxxxxxx>
"Acked-by:" in the future please :)
