Messages in this thread | | | Subject | Re: v2.6.26-rc7/cgroups: circular locking dependency | From | Peter Zijlstra <> | Date | Sun, 22 Jun 2008 17:50:21 +0200 |
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On Mon, 2008-06-23 at 00:34 +0900, KOSAKI Motohiro wrote: > 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().
Looks like Max forgot to test with lockdep enabled...
Well, someone should when you change the online map.
Max, Paul, can we handle this in update_sched_domains() instead?
> -> #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. > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/
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