Messages in this thread | | | Date | Mon, 23 Jun 2008 00:34:04 +0900 | From | "KOSAKI Motohiro" <> | Subject | Re: v2.6.26-rc7/cgroups: circular locking dependency |
| |
CC'ed Paul Jackson
it seems typical ABBA deadlock. I think cpuset use cgrou_lock() by mistake.
IMHO, cpuset_handle_cpuhp() sholdn't use cgroup_lock() and shouldn't call rebuild_sched_domains().
-> #1 (cgroup_mutex){--..}: [<c015a435>] __lock_acquire+0xf45/0x1040 [<c015a5c8>] lock_acquire+0x98/0xd0 [<c05416d1>] mutex_lock_nested+0xb1/0x300 [<c0160e6f>] cgroup_lock+0xf/0x20 cgroup_lock [<c0164750>] cpuset_handle_cpuhp+0x20/0x180 [<c014ea77>] notifier_call_chain+0x37/0x70 [<c014eae9>] __raw_notifier_call_chain+0x19/0x20 [<c051f8c8>] _cpu_down+0x78/0x240 cpu_hotplug.lock [<c051fabb>] cpu_down+0x2b/0x40 cpu_add_remove_lock [<c0520cd9>] store_online+0x39/0x80 [<c02f627b>] sysdev_store+0x2b/0x40 [<c01d3372>] sysfs_write_file+0xa2/0x100 [<c0195486>] vfs_write+0x96/0x130 [<c0195b4d>] sys_write+0x3d/0x70 [<c010831b>] sysenter_past_esp+0x78/0xd1 [<ffffffff>] 0xffffffff
-> #0 (&cpu_hotplug.lock){--..}: [<c0159fe5>] __lock_acquire+0xaf5/0x1040 [<c015a5c8>] lock_acquire+0x98/0xd0 [<c05416d1>] mutex_lock_nested+0xb1/0x300 [<c015efbc>] get_online_cpus+0x2c/0x40 cpu_hotplug.lock [<c0163e6d>] rebuild_sched_domains+0x7d/0x3a0 [<c01653a4>] cpuset_common_file_write+0x204/0x440 cgroup_lock [<c0162bc7>] cgroup_file_write+0x67/0x130 [<c0195486>] vfs_write+0x96/0x130 [<c0195b4d>] sys_write+0x3d/0x70 [<c010831b>] sysenter_past_esp+0x78/0xd1 [<ffffffff>] 0xffffffff
> Hi, > > I decided to see what cgroups is all about, and followed the instructions > in Documentation/cgroups.txt :-) It happened when I did this: > > [root@damson /dev/cgroup/Vegard 0] > # echo 1 > cpuset.cpus > > I can also provide the kernel config if necessary. > > > Vegard > > > ======================================================= > [ INFO: possible circular locking dependency detected ] > 2.6.26-rc7 #25 > ------------------------------------------------------- > bash/10032 is trying to acquire lock: > (&cpu_hotplug.lock){--..}, at: [<c015efbc>] get_online_cpus+0x2c/0x40 > > but task is already holding lock: > (cgroup_mutex){--..}, at: [<c0160e6f>] cgroup_lock+0xf/0x20 > > which lock already depends on the new lock.
| |