Test-case on Xenial; $ ls -1d /sys/devices/system/cpu/cpu[0-9]* /sys/devices/system/cpu/cpu0 /sys/devices/system/cpu/cpu1
Original -------- $ uname -rv 4.4.0-144-generic #170-Ubuntu SMP Thu Mar 14 11:56:20 UTC 2019 $ sudo insmod kmod-stopper/kmod-stopper.ko [ 74.198379] mod_init() :: this cpu = 0x1, that cpu = 0x0 [ 74.199613] mod_init() :: that_cpu_stopper_task = ffff88003d80e600, comm = migration/0 [ 74.206194] kp2/stop_two_cpus() :: this cpu = 0x1, that cpu = 0x0 [ 74.206196] do_nothing() :: this cpu = 0x0, that cpu = 0x1 [ 74.206201] kp1/pick_next_task_fair() :: this cpu = 0x0, that cpu = 0x1 [ 74.206203] kp1/pick_next_task_fair() :: before sleep (1000 msecs) [ 74.212759] kp2/stop_two_cpus() :: before sleep (500 msecs) [ 74.710138] kp2/stop_two_cpus() :: after sleep (500 msecs) [ 75.198324] kp1/pick_next_task_fair() :: after sleep (1000 msecs) [ 75.199814] kp1/pick_next_task_fair() :: stopping other cpu... <hang> The test-case only failed 2 out of 50+ tests. Patched: ------- $ uname -rv 4.4.0-144-generic #170+test20190320b1 SMP Wed Mar 20 18:35:06 UTC 2019 $ sudo insmod kmod-stopper/kmod-stopper.ko [ 85.958527] mod_init() :: this cpu = 0x1, that cpu = 0x0 [ 85.965876] mod_init() :: that_cpu_stopper_task = ffff88003d80e600, comm = migration/0 [ 85.993446] kp2/stop_two_cpus() :: this cpu = 0x1, that cpu = 0x0 [ 85.993471] do_nothing() :: this cpu = 0x0, that cpu = 0x1 [ 85.993477] kp1/pick_next_task_fair() :: this cpu = 0x0, that cpu = 0x1 [ 85.993480] kp1/pick_next_task_fair() :: before sleep (1000 msecs) [ 86.019469] kp2/stop_two_cpus() :: before sleep (500 msecs) [ 86.521688] kp2/stop_two_cpus() :: after sleep (500 msecs) [ 86.987662] kp1/pick_next_task_fair() :: after sleep (1000 msecs) [ 86.989427] kp1/pick_next_task_fair() :: stopping other cpu... [ 86.991109] do_nothing() :: this cpu = 0x1, that cpu = 0x0 [ 86.992615] do_nothing() :: this cpu = 0x1, that cpu = 0x0 <finished> It passes every time (50+ tests). -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1821259 Title: Hard lockup in 2 CPUs due to deadlock in cpu_stoppers To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1821259/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
