SRU Justification: Impact: Right now whenever the bcache module gets loaded, we can see softlockup warnings caused by the writeback thread.
Fix: A patch picked from 3.17-rc1 will avoid those warnings. I bundled this with one patch from upstream that avoids a crash on shutdown, which is also caused by the fact that the writeback thread is not always started now. A third patch which was sent upstream addresses the same crash when modifying the writeback_running sysfs variable. This also adds a check for the writeback thread to be running. Testcase(s): Define caching and backing device with (bcache-tools): make-bcache -B <backing dev> -C <cache dev> This will trigger the hung task after a while. echo 0 >/sys/block/bcache0/bcache/writeback_running This will trigger a kernel BUG. Both issues are gone with the patch series applied. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1357295 Title: bcache_writebac blocks and goes silent on trusty kernel 3.13.0-24-generic #47-Ubuntu To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1357295/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
