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; }
