Thank you for the help, Christopher. This is a hard bug to reproduce. I think I saw it before because a faulty usb cable caused unexpected, abrupt and very short disconnects of my backup hard drive, and the oops happened sometimes after that. Since I swapped the cable out, I don't see either problem. For all I know the disconnects may have been only of one pin in the cable, and lasted less than a second.
Now, when I try to quickly unplug and replug the USB cable I get this, without the "unable to enumerate" errors: Mar 25 13:54:07 rf kernel: [167326.208131] usb 2-1.1: USB disconnect, address 21 Mar 25 13:54:07 rf kernel: [167326.322190] EXT4-fs error (device sdd3): ext4_find_entry: inode #2: (comm gnome-panel) reading directory lblock 0 Mar 25 13:54:08 rf kernel: [167327.227575] usb 2-1.1: new high speed USB device using ehci_hcd and address 22 Mar 25 13:54:09 rf kernel: [167327.979904] scsi12 : usb-storage 2-1.1:1.0 ... I also note that the same drive now shows up as a "high speed" device, not a "full speed" device, so I guess the bad cable was giving me a USB 1.1 connection or something. At any rate, I'm reluctant to try to reproduce it too much. But I'll watch for it. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/819412 Title: Kernel Oops - BUG: unable to handle kernel NULL pointer dereference at 0000000000000008; RIP: 0010:[<ffffffffa0056882>] [<ffffffffa0056882>] ses_enclosure_data_process+0x1a2/0x380 [ses] To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/819412/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
