Hi, I've just tried out Ubuntu's kernel PPA and this issue is still there. At least I didn't screw something up on my personal builds. I've used the following for activating USB dynamic debug: echo "file drivers/usb/* +p" > /sys/kernel/debug/dynamic_debug/control Let me know if I should have done something else. Kernel log stays quiet until I do echo 1 > remove, and it goes nuts. http://www.arter97.com/usblog.txt.xz (uncompressed size 27M) Please have a look. Thanks. On Thu, Dec 13, 2018 at 6:46 AM Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: > > On Thu, 13 Dec 2018, Ju Hyung Park wrote: > > > Hi, > > > > On Thu, Dec 13, 2018 at 3:17 AM Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > > > > > > On Thu, Dec 13, 2018 at 01:28:36AM +0900, Ju Hyung Park wrote: > > > > Hi, > > > > > > > > I'm using the latest stable tree v4.19.8, > > > > and I'm noticing kworker and ksoftirqd hogging up the CPU > > > > upon removing any USB devices on my laptop. > > > > > > > > This issue was not present on any kernels below v4.19. > > > > > > Can you run 'git bisect' to track down the offending commit? > > > > I can, but I was hoping to get some pointers from the maintainers to > > quickly get down to the culprit. > > > > I will run 'git bisect' later when I get a chance, > > would greatly appreciate it if someone hints me towards possible culprits. > > > > I should probably also mention that the kernel seems to be fine > > with physical removal. > > > > Only when I do soft removal: sysfs echo 1 > remove > > seems to cause the issue. > > The information you provided wasn't ideal for suggesting culprits. > You apparently don't have CONFIG_FRAME_POINTER enabled (which makes the > backtrace very difficult to interpret), and you didn't turn on dynamic > debugging for the usbcore and xhci-hcd drivers (which makes the dmesg > log much less complete). > > For what it's worth, I just tried doing the same thing under Fedora's > 4.19.5 kernel. Nothing went wrong; CPU usage is 99.8% idle. > > Alan Stern >
