Messages in this thread | | | Date | Sat, 21 Jun 2008 19:38:59 +0200 | Subject | v2.6.26-rc7/cgroups: circular locking dependency | From | Vegard Nossum <> |
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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. the existing dependency chain (in reverse order) is: -> #1 (cgroup_mutex){--..}: [<c015a435>] __lock_acquire+0xf45/0x1040 [<c015a5c8>] lock_acquire+0x98/0xd0 [<c05416d1>] mutex_lock_nested+0xb1/0x300 [<c0160e6f>] cgroup_lock+0xf/0x20 [<c0164750>] cpuset_handle_cpuhp+0x20/0x180 [<c014ea77>] notifier_call_chain+0x37/0x70 [<c014eae9>] __raw_notifier_call_chain+0x19/0x20 [<c051f8c8>] _cpu_down+0x78/0x240 [<c051fabb>] cpu_down+0x2b/0x40 [<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 [<c0163e6d>] rebuild_sched_domains+0x7d/0x3a0 [<c01653a4>] cpuset_common_file_write+0x204/0x440 [<c0162bc7>] cgroup_file_write+0x67/0x130 [<c0195486>] vfs_write+0x96/0x130 [<c0195b4d>] sys_write+0x3d/0x70 [<c010831b>] sysenter_past_esp+0x78/0xd1 [<ffffffff>] 0xffffffff other info that might help us debug this: 1 lock held by bash/10032: #0: (cgroup_mutex){--..}, at: [<c0160e6f>] cgroup_lock+0xf/0x20 stack backtrace: Pid: 10032, comm: bash Not tainted 2.6.26-rc7 #25 [<c0157ae7>] print_circular_bug_tail+0x77/0x90 [<c0159fe5>] __lock_acquire+0xaf5/0x1040 [<c015a5c8>] lock_acquire+0x98/0xd0 [<c015efbc>] ? get_online_cpus+0x2c/0x40 [<c05416d1>] mutex_lock_nested+0xb1/0x300 [<c015efbc>] ? get_online_cpus+0x2c/0x40 [<c015efbc>] ? get_online_cpus+0x2c/0x40 [<c015efbc>] get_online_cpus+0x2c/0x40 [<c0163e6d>] rebuild_sched_domains+0x7d/0x3a0 [<c0158e65>] ? mark_held_locks+0x65/0x80 [<c0190ac5>] ? kfree+0xb5/0x120 [<c027736a>] ? heap_free+0xa/0x10 [<c027736a>] ? heap_free+0xa/0x10 [<c01653a4>] cpuset_common_file_write+0x204/0x440 [<c0163c30>] ? started_after+0x0/0x70 [<c010e585>] ? native_sched_clock+0xb5/0x110 [<c0162e10>] ? started_after+0x0/0x70 [<c0164c80>] ? cpuset_test_cpumask+0x0/0x20 [<c0164ca0>] ? cpuset_change_cpumask+0x0/0x20 [<c0162bc7>] cgroup_file_write+0x67/0x130 [<c01651a0>] ? cpuset_common_file_write+0x0/0x440 [<c010e585>] ? native_sched_clock+0xb5/0x110 [<c0195486>] vfs_write+0x96/0x130 [<c0162b60>] ? cgroup_file_write+0x0/0x130 [<c0195b4d>] sys_write+0x3d/0x70 [<c010831b>] sysenter_past_esp+0x78/0xd1 =======================
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