lkml.org 
[lkml]   [2008]   [Jun]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
Subjectv2.6.26-rc7/cgroups: circular locking dependency
From
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
=======================



\
 
 \ /
  Last update: 2008-06-21 19:41    [W:0.059 / U:3.576 seconds]
©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site