On Thu, Nov 19, 2020 at 01:50:13PM -0500, Alberto Sentieri wrote: > > > However, just before the lock, I got this sequence: > > > > > > [ 387.326795] usb 1-1.5.3.1: usbdev_do_ioctl: SUBMITURB > > > [ 387.326801] usb 1-1.5.3.1: userurb 0000000000000000, ep1 int-in, length > > > 64 > > > [ 387.327531] usb 1-1.5.3.1: urb complete > > > [ 387.327539] usb 1-1.5.3.1: userurb pK-error, ep1 int-out, > > > actual_length 64 status 0 > > > [ 387.327582] usb 1-1.5.3.1: usbdev_do_ioctl: REAPURBNDELAY > > > [ 387.327590] usb 1-1.5.3.1: reap 0000000000000000 > > > [ 387.327598] usb 1-1.5.3.1: usbdev_do_ioctl: REAPURBNDELAY > > > [ 388.109400] usb 3-1.5.7.1: usbdev_do_ioctl: REAPURBNDELAY > > > [ 388.110032] usb 3-1.6.7.1: usbdev_do_ioctl: REAPURBNDELAY > > > [ 388.110169] usb 3-1.5.5.1: usbdev_do_ioctl: REAPURBNDELAY > > > [ 388.110605] usb 3-1.6.5.1: usbdev_do_ioctl: REAPURBNDELAY > > > [ 388.111394] usb 3-1.1.1: usbdev_do_ioctl: REAPURBNDELAY > > > [ 388.403278] usb 3-1.6.4.1: usbdev_do_ioctl: REAPURBNDELAY > > > [ 388.404011] usb 3-1.5.1.1: usbdev_do_ioctl: REAPURBNDELAY > > > [ 388.404344] usb 3-1.6.3.1: usbdev_do_ioctl: REAPURBNDELAY > > > [ 388.404649] usb 3-1.4.1: usbdev_do_ioctl: REAPURBNDELAY > > > [ 388.404790] usb 3-1.3.1: usbdev_do_ioctl: REAPURBNDELAY > > > [ 388.405283] usb 3-1.5.3.1: usbdev_do_ioctl: REAPURBNDELAY > > > [ 388.407828] usb 3-1.6.1.1: usbdev_do_ioctl: REAPURBNDELAY > > > [ 388.408771] usb 3-1.5.4.1: usbdev_do_ioctl: REAPURBNDELAY > > > [ 388.409155] usb 3-1.5.2.1: usbdev_do_ioctl: REAPURBNDELAY > > > [ 388.409452] usb 3-1.5.6.1: usbdev_do_ioctl: REAPURBNDELAY > > > [ 388.409743] usb 3-1.6.6.1: usbdev_do_ioctl: REAPURBNDELAY > > > [ 388.409848] usb 3-1.2.1: usbdev_do_ioctl: REAPURBNDELAY > > > [ 388.410840] usb 3-1.6.2.1: usbdev_do_ioctl: REAPURBNDELAY > > This rapid sequence of reap requests with no completions or actual > > reaps is odd. Is this the sort of thing you expect your program to > > do? Maybe you can add some debugging output to the program. > What apparently happened before that (but unfortunately I did not capture it > this time) is that the particular device return errno -71 in some URBs, > without de-enumerating. That's actually quite bad. -71 (-EPROTO) indicates a serious error in the USB protocol. Most often it means that the kernel did not receive a reply packet from the device -- this could be caused by the device's firmware crashing or a USB cable failing. In a well-functioning system it should never occur. > However, I am only seeing userurbs with status 0 in > my the netconsole capture, before the ones with status -108 (just before the > lock). So, if error -71 happened, all URBs are reaped and the devices are > then closed. Usually I see error -71 in the program log happening for a few > devices at the same time. That probably means there's something wrong with a hub they are all connected to. But of course, a problem in a hub wouldn't explain why the whole system freezes. > After closing the interface, the program opens it > again. The return from open should be a valid file descriptor, otherwise it > would fail. After opening the device successfully it starts submitting urbs, > and error -108 is coming back, telling me that the device just opened is not > open. It means that the device is no longer present. Perhaps it was logically (if not physically) disconnected after the open but before the URBs were submitted. > It just came to my attention now: maybe something to be investigated is what > the kernel does if a interface is closed due to a URB error and immediately > opened again. In itself, that should work perfectly. But whatever caused the USB error could go on to cause other things to go wrong. It might help to see a usbmon trace. You merely have to send the data from /sys/kernel/debug/usb/usbmon/1u (or 3u, or even both -- the number refers to the USB bus being monitored) through a UDP pipe, using netcat or something similar, to another computer which could safely store the output. Alan Stern
