FYI i could reproduce a hang in dd doing the following: truncate -s 1G foo sudo losetup -f --show foo echo "0 2097152 zero" | sudo dmsetup create zero1 echo "0 2097152 snapshot /dev/mapper/zero1 /dev/loop0 n 128" | sudo dmsetup create clean1 sudo dd if=/dev/zero of=/dev/mapper/clean1 bs=1M count=1024
Using strace, the command hangs partway through: read(0, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1048576) = 1048576 write(1, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1048576 I can ctrl-c out of strace but the resulting dd process is completely hung and unkillalble Note that this is running in a (vmware fusion) vm. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1023755 Title: Precise kernel locks up while dd to /dev/mapper files > 1Gb (was: Unable to delete volume) To manage notifications about this bug go to: https://bugs.launchpad.net/cinder/+bug/1023755/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
