[Bugme-new] [Bug 13493] New: cpufreq: INFO: possible circular locking dependency detected

bugzilla-daemon at bugzilla.kernel.org bugzilla-daemon at bugzilla.kernel.org
Tue Jun 9 12:15:43 PDT 2009


http://bugzilla.kernel.org/show_bug.cgi?id=13493

           Summary: cpufreq: INFO: possible circular locking dependency
                    detected
           Product: Power Management
           Version: 2.5
    Kernel Version: 2.6.30-rc8
          Platform: All
        OS/Version: Linux
              Tree: Mainline
            Status: NEW
          Severity: normal
          Priority: P1
         Component: cpufreq
        AssignedTo: cpufreq at vger.kernel.org
        ReportedBy: nm127 at freemail.hu
        Regression: No


Created an attachment (id=21832)
 --> (http://bugzilla.kernel.org/attachment.cgi?id=21832)
dmesg 2.6.30-rc8

Trying to set "powersave" governor on EeePC 901 causes possible circular
locking dependency message in dmesg.

Steps to reproduce:
1. boot the system
2. modprobe -k acpi-cpufreq
3. modprobe -k cpufreq-ondemand
4. echo powersave >/sys/devices/system/cpu/cpu0/cpufreq/scaling_governor

Actual result:
[   77.802623] =======================================================
[   77.802807] [ INFO: possible circular locking dependency detected ]
[   77.802913] 2.6.30-rc8 #1
[   77.802999] -------------------------------------------------------
[   77.803102] bash/2317 is trying to acquire lock:
[   77.803197]  (&(&dbs_info->work)->work){+.+...}, at: [<c013abd8>]
__cancel_work_timer+0x8f/0x190
[   77.803502] 
[   77.803506] but task is already holding lock:
[   77.803673]  (dbs_mutex){+.+.+.}, at: [<f94dea44>]
cpufreq_governor_dbs+0x296/0x322 [cpufreq_ondemand]
[   77.803981] 
[   77.803985] which lock already depends on the new lock.
[   77.803990] 
[   77.804231] 
[   77.804235] the existing dependency chain (in reverse order) is:
[   77.804408] 
[   77.804412] -> #2 (dbs_mutex){+.+.+.}:
[   77.804733]        [<c014d3b5>] __lock_acquire+0xf85/0x128d
[   77.804890]        [<c014d770>] lock_acquire+0xb3/0xd6
[   77.804928]        [<c034c432>] mutex_lock_nested+0x45/0x2b0
[   77.804928]        [<f94de828>] cpufreq_governor_dbs+0x7a/0x322
[cpufreq_ondemand]
[   77.804928]        [<c02cabfd>] __cpufreq_governor+0x9d/0xd3
[   77.804928]        [<c02cae43>] __cpufreq_set_policy+0xe7/0x11f
[   77.804928]        [<c02cb7bc>] store_scaling_governor+0x197/0x1bf
[   77.804928]        [<c02cc19e>] store+0x48/0x61
[   77.804928]        [<c01de7f8>] sysfs_write_file+0xb9/0xe4
[   77.804928]        [<c01a1954>] vfs_write+0x8a/0x12e
[   77.804928]        [<c01a1a91>] sys_write+0x3b/0x60
[   77.804928]        [<c01031a4>] sysenter_do_call+0x12/0x38
[   77.804928]        [<ffffffff>] 0xffffffff
[   77.804928] 
[   77.804928] -> #1 (&per_cpu(cpu_policy_rwsem, cpu)){+++++.}:
[   77.804928]        [<c014d3b5>] __lock_acquire+0xf85/0x128d
[   77.804928]        [<c014d770>] lock_acquire+0xb3/0xd6
[   77.804928]        [<c034ccae>] down_write+0x2a/0x46
[   77.804928]        [<c02cbb7d>] lock_policy_rwsem_write+0x33/0x5b
[   77.804928]        [<f94de527>] do_dbs_timer+0x4b/0x2d2 [cpufreq_ondemand]
[   77.804928]        [<c013a50f>] worker_thread+0x1ad/0x28a
[   77.804928]        [<c013d8ae>] kthread+0x45/0x6b
[   77.804928]        [<c0103d63>] kernel_thread_helper+0x7/0x10
[   77.804928]        [<ffffffff>] 0xffffffff
[   77.804928] 
[   77.804928] -> #0 (&(&dbs_info->work)->work){+.+...}:
[   77.804928]        [<c014d145>] __lock_acquire+0xd15/0x128d
[   77.804928]        [<c014d770>] lock_acquire+0xb3/0xd6
[   77.804928]        [<c013abfe>] __cancel_work_timer+0xb5/0x190
[   77.804928]        [<c013ace4>] cancel_delayed_work_sync+0xb/0xd
[   77.804928]        [<f94dea58>] cpufreq_governor_dbs+0x2aa/0x322
[cpufreq_ondemand]
[   77.804928]        [<c02cabfd>] __cpufreq_governor+0x9d/0xd3
[   77.804928]        [<c02cae2d>] __cpufreq_set_policy+0xd1/0x11f
[   77.804928]        [<c02cb7bc>] store_scaling_governor+0x197/0x1bf
[   77.804928]        [<c02cc19e>] store+0x48/0x61
[   77.804928]        [<c01de7f8>] sysfs_write_file+0xb9/0xe4
[   77.804928]        [<c01a1954>] vfs_write+0x8a/0x12e
[   77.804928]        [<c01a1a91>] sys_write+0x3b/0x60
[   77.804928]        [<c01031a4>] sysenter_do_call+0x12/0x38
[   77.804928]        [<ffffffff>] 0xffffffff
[   77.804928] 
[   77.804928] other info that might help us debug this:
[   77.804928] 
[   77.804928] 3 locks held by bash/2317:
[   77.804928]  #0:  (&buffer->mutex){+.+.+.}, at: [<c01de764>]
sysfs_write_file+0x25/0xe4
[   77.804928]  #1:  (&per_cpu(cpu_policy_rwsem, cpu)){+++++.}, at:
[<c02cbb7d>] lock_policy_rwsem_write+0x33/0x5b
[   77.804928]  #2:  (dbs_mutex){+.+.+.}, at: [<f94dea44>]
cpufreq_governor_dbs+0x296/0x322 [cpufreq_ondemand]
[   77.804928] 
[   77.804928] stack backtrace:
[   77.804928] Pid: 2317, comm: bash Not tainted 2.6.30-rc8 #1
[   77.804928] Call Trace:
[   77.804928]  [<c034ac15>] ? printk+0xf/0x12
[   77.804928]  [<c014c061>] print_circular_bug_tail+0xa3/0xae
[   77.804928]  [<c014d145>] __lock_acquire+0xd15/0x128d
[   77.804928]  [<c014d770>] lock_acquire+0xb3/0xd6
[   77.804928]  [<c013abd8>] ? __cancel_work_timer+0x8f/0x190
[   77.804928]  [<c013abfe>] __cancel_work_timer+0xb5/0x190
[   77.804928]  [<c013abd8>] ? __cancel_work_timer+0x8f/0x190
[   77.804928]  [<c034c657>] ? mutex_lock_nested+0x26a/0x2b0
[   77.804928]  [<c014b985>] ? trace_hardirqs_on_caller+0x103/0x124
[   77.804928]  [<c034c683>] ? mutex_lock_nested+0x296/0x2b0
[   77.804928]  [<c013ace4>] cancel_delayed_work_sync+0xb/0xd
[   77.804928]  [<f94dea58>] cpufreq_governor_dbs+0x2aa/0x322
[cpufreq_ondemand]
[   77.804928]  [<c014180c>] ? __blocking_notifier_call_chain+0x40/0x4c
[   77.804928]  [<c02cabfd>] __cpufreq_governor+0x9d/0xd3
[   77.804928]  [<c02cae2d>] __cpufreq_set_policy+0xd1/0x11f
[   77.804928]  [<c02cb7bc>] store_scaling_governor+0x197/0x1bf
[   77.804928]  [<c02cc28d>] ? handle_update+0x0/0xd
[   77.804928]  [<c02cbb7d>] ? lock_policy_rwsem_write+0x33/0x5b
[   77.804928]  [<c02cb625>] ? store_scaling_governor+0x0/0x1bf
[   77.804928]  [<c02cc19e>] store+0x48/0x61
[   77.804928]  [<c01de7f8>] sysfs_write_file+0xb9/0xe4
[   77.804928]  [<c01de73f>] ? sysfs_write_file+0x0/0xe4
[   77.804928]  [<c01a1954>] vfs_write+0x8a/0x12e
[   77.804928]  [<c01a1a91>] sys_write+0x3b/0x60
[   77.804928]  [<c01031a4>] sysenter_do_call+0x12/0x38

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