i initially reported this bug as rsync one : https://bugs.launchpad.net/ubuntu/+source/rsync/+bug/624978
but changed my mind after I added MARK in rsylogd each 5 minutes and see this in kern.log at moment corresponding to rsync (and before freeze) Aug 26 23:09:12 amp-desktop rsyslogd: -- MARK -- Aug 26 23:14:12 amp-desktop rsyslogd: -- MARK -- Aug 26 23:19:12 amp-desktop rsyslogd: -- MARK -- Aug 26 23:24:12 amp-desktop rsyslogd: -- MARK -- Aug 26 23:26:46 amp-desktop kernel: [ 3472.248086] usb 1-3: reset high speed USB device using ehci_hcd and address 2 Aug 26 23:28:36 amp-desktop kernel: [ 3582.780087] usb 1-3: reset high speed USB device using ehci_hcd and address 2 Aug 26 23:34:12 amp-desktop rsyslogd: -- MARK -- Aug 26 23:58:24 amp-desktop kernel: imklog 4.2.0, log source = /proc/kmsg started. -- system hang while doing rsync from usb2 disk https://bugs.launchpad.net/bugs/626834 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs