On Fri, Mar 8, 2024 at 4:35 AM Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: > > On Mon, Mar 04, 2024 at 08:10:02PM +0800, Sam Sun wrote: > > Dear developers and maintainers, > > > > We encountered a task hung in function hub_activate(). It was reported > > before by Syzbot several years ago > > (https://groups.google.com/g/syzkaller-lts-bugs/c/_komEgHj03Y/m/rbcVKyLXBwAJ), > > but no repro at that time. We have a C repro this time and kernel > > config is attached to this email. The bug report is listed below. > > > If you have any questions, please contact us. > > > > Reported by Yue Sun <samsun1006219@xxxxxxxxx> > > Reported by xingwei lee <xrivendell7@xxxxxxxxx> > > Yue: > > Can you try testing the patch below? Thanks. > > Alan Stern > > > > Index: usb-devel/drivers/usb/core/sysfs.c > =================================================================== > --- usb-devel.orig/drivers/usb/core/sysfs.c > +++ usb-devel/drivers/usb/core/sysfs.c > @@ -1168,14 +1168,24 @@ static ssize_t interface_authorized_stor > { > struct usb_interface *intf = to_usb_interface(dev); > bool val; > + struct kernfs_node *kn; > > if (kstrtobool(buf, &val) != 0) > return -EINVAL; > > - if (val) > + if (val) { > usb_authorize_interface(intf); > - else > - usb_deauthorize_interface(intf); > + } else { > + /* > + * Prevent deadlock if another process is concurrently > + * trying to unregister intf or its parent device. > + */ > + kn = sysfs_break_active_protection(&dev->kobj, &attr->attr); > + if (kn) { > + usb_deauthorize_interface(intf); > + sysfs_unbreak_active_protection(kn); > + } > + } > > return count; > } Hi Alan, I applied this patch on the latest linux git commit and tested several times. There is no more task hung report, so I think it works. Should I try this on usb-dev branch? Best, Yue
