Re: 2.6.19.1-rt14-smp circular locking dependency
From: Mike Galbraith
Date: Thu Dec 14 2006 - 06:39:52 EST
On Thu, 2006-12-14 at 10:59 +0100, Ingo Molnar wrote:
> * Mike Galbraith <efault@xxxxxx> wrote:
>
> > Greetings,
> >
> > Lockdep doesn't approve of cpufreq, and seemingly with cause... I had
> > to poke SysRq-O.
>
> hm ... this must be an upstream problem too, right? -rt shouldnt change
> anything in this area (in theory).
Yeah, it is. It didn't seize up, but lockdep griped. Trace from
2.6.19.1 below, cc added.
[ 129.309689] Disabling non-boot CPUs ...
[ 129.335627]
[ 129.335631] =======================================================
[ 129.343584] [ INFO: possible circular locking dependency detected ]
[ 129.350028] 2.6.19.1-smp #77
[ 129.352973] -------------------------------------------------------
[ 129.359379] s2ram/6178 is trying to acquire lock:
[ 129.364178] (cpu_bitmask_lock){--..}, at: [<c13e23dd>] mutex_lock+0x8/0xa
[ 129.371298]
[ 129.371300] but task is already holding lock:
[ 129.377274] (workqueue_mutex){--..}, at: [<c13e23dd>] mutex_lock+0x8/0xa
[ 129.384277]
[ 129.384279] which lock already depends on the new lock.
[ 129.384281]
[ 129.392647]
[ 129.392649] the existing dependency chain (in reverse order) is:
[ 129.400294]
[ 129.400296] -> #3 (workqueue_mutex){--..}:
[ 129.406083] [<c103dd54>] add_lock_to_list+0x3b/0x87
[ 129.411895] [<c1040420>] __lock_acquire+0xb75/0xc1a
[ 129.417697] [<c10407f1>] lock_acquire+0x5d/0x79
[ 129.423135] [<c13e21ad>] __mutex_lock_slowpath+0x6e/0x296
[ 129.429470] [<c13e23dd>] mutex_lock+0x8/0xa
[ 129.434562] [<c1035815>] __create_workqueue+0x5f/0x16c
[ 129.440615] [<c1312a83>] cpufreq_governor_dbs+0x2d6/0x32c
[ 129.446943] [<c131073e>] __cpufreq_governor+0x22/0x166
[ 129.453009] [<c13112d9>] __cpufreq_set_policy+0xe6/0x132
[ 129.459267] [<c131153a>] store_scaling_governor+0xa8/0x1e8
[ 129.465676] [<c1310dbc>] store+0x37/0x4a
[ 129.470517] [<c10b743c>] sysfs_write_file+0x8a/0xcb
[ 129.476301] [<c1077bb8>] vfs_write+0xa6/0x170
[ 129.481584] [<c107826c>] sys_write+0x3d/0x64
[ 129.486761] [<c1003173>] syscall_call+0x7/0xb
[ 129.492018] [<b7bece0e>] 0xb7bece0e
[ 129.496389] [<ffffffff>] 0xffffffff
[ 129.500789]
[ 129.500791] -> #2 (dbs_mutex){--..}:
[ 129.508253] [<c103dd54>] add_lock_to_list+0x3b/0x87
[ 129.516360] [<c1040420>] __lock_acquire+0xb75/0xc1a
[ 129.524405] [<c10407f1>] lock_acquire+0x5d/0x79
[ 129.532057] [<c13e21ad>] __mutex_lock_slowpath+0x6e/0x296
[ 129.540608] [<c13e23dd>] mutex_lock+0x8/0xa
[ 129.547856] [<c13128bc>] cpufreq_governor_dbs+0x10f/0x32c
[ 129.556348] [<c131073e>] __cpufreq_governor+0x22/0x166
[ 129.564548] [<c13112d9>] __cpufreq_set_policy+0xe6/0x132
[ 129.572865] [<c131153a>] store_scaling_governor+0xa8/0x1e8
[ 129.581379] [<c1310dbc>] store+0x37/0x4a
[ 129.588249] [<c10b743c>] sysfs_write_file+0x8a/0xcb
[ 129.596053] [<c1077bb8>] vfs_write+0xa6/0x170
[ 129.603290] [<c107826c>] sys_write+0x3d/0x64
[ 129.610398] [<c1003173>] syscall_call+0x7/0xb
[ 129.617624] [<b7bece0e>] 0xb7bece0e
[ 129.623954] [<ffffffff>] 0xffffffff
[ 129.630230]
[ 129.630232] -> #1 (&policy->lock){--..}:
[ 129.639563] [<c103dd54>] add_lock_to_list+0x3b/0x87
[ 129.647225] [<c1040420>] __lock_acquire+0xb75/0xc1a
[ 129.654928] [<c10407f1>] lock_acquire+0x5d/0x79
[ 129.662217] [<c13e21ad>] __mutex_lock_slowpath+0x6e/0x296
[ 129.670439] [<c13e23dd>] mutex_lock+0x8/0xa
[ 129.677387] [<c131144e>] cpufreq_set_policy+0x35/0x79
[ 129.685230] [<c1311a79>] cpufreq_add_dev+0x2b8/0x461
[ 129.692970] [<c1264128>] sysdev_driver_register+0x63/0xaa
[ 129.701152] [<c1311d58>] cpufreq_register_driver+0x68/0xfd
[ 129.709430] [<c1610cf9>] cpufreq_p4_init+0x3a/0x51
[ 129.717006] [<c100049b>] init+0x112/0x311
[ 129.723784] [<c1003dff>] kernel_thread_helper+0x7/0x18
[ 129.731709] [<ffffffff>] 0xffffffff
[ 129.738040]
[ 129.738042] -> #0 (cpu_bitmask_lock){--..}:
[ 129.747694] [<c103f875>] print_circular_bug_tail+0x30/0x66
[ 129.756036] [<c1040231>] __lock_acquire+0x986/0xc1a
[ 129.763786] [<c10407f1>] lock_acquire+0x5d/0x79
[ 129.771202] [<c13e21ad>] __mutex_lock_slowpath+0x6e/0x296
[ 129.779450] [<c13e23dd>] mutex_lock+0x8/0xa
[ 129.786496] [<c1044326>] lock_cpu_hotplug+0x22/0x82
[ 129.794243] [<c131110b>] cpufreq_driver_target+0x27/0x5d
[ 129.802449] [<c1311c69>] cpufreq_cpu_callback+0x47/0x6c
[ 129.810548] [<c1032316>] notifier_call_chain+0x2c/0x39
[ 129.818555] [<c103233f>] raw_notifier_call_chain+0x8/0xa
[ 129.826752] [<c10440a9>] _cpu_down+0x4c/0x219
[ 129.833942] [<c1044483>] disable_nonboot_cpus+0x92/0x14b
[ 129.842105] [<c1049e2a>] enter_state+0x7e/0x1bc
[ 129.849530] [<c104a00b>] state_store+0xa3/0xac
[ 129.856813] [<c10b7110>] subsys_attr_store+0x20/0x25
[ 129.864627] [<c10b743c>] sysfs_write_file+0x8a/0xcb
[ 129.872403] [<c1077bb8>] vfs_write+0xa6/0x170
[ 129.879661] [<c107826c>] sys_write+0x3d/0x64
[ 129.886801] [<c1003173>] syscall_call+0x7/0xb
[ 129.894041] [<b7e63e0e>] 0xb7e63e0e
[ 129.900412] [<ffffffff>] 0xffffffff
[ 129.906765]
[ 129.906766] other info that might help us debug this:
[ 129.906768]
[ 129.920864] 2 locks held by s2ram/6178:
[ 129.926703] #0: (cpu_add_remove_lock){--..}, at: [<c13e23dd>] mutex_lock+0x8/0xa
[ 129.936543] #1: (workqueue_mutex){--..}, at: [<c13e23dd>] mutex_lock+0x8/0xa
[ 129.946078]
[ 129.946080] stack backtrace:
[ 129.954729] [<c10041e3>] dump_trace+0x1c1/0x1f0
[ 129.961574] [<c100422c>] show_trace_log_lvl+0x1a/0x30
[ 129.968917] [<c1004967>] show_trace+0x12/0x14
[ 129.975548] [<c1004a88>] dump_stack+0x19/0x1b
[ 129.982177] [<c103f8a2>] print_circular_bug_tail+0x5d/0x66
[ 129.989940] [<c1040231>] __lock_acquire+0x986/0xc1a
[ 129.997109] [<c10407f1>] lock_acquire+0x5d/0x79
[ 130.003939] [<c13e21ad>] __mutex_lock_slowpath+0x6e/0x296
[ 130.011630] [<c13e23dd>] mutex_lock+0x8/0xa
[ 130.018086] [<c1044326>] lock_cpu_hotplug+0x22/0x82
[ 130.025259] [<c131110b>] cpufreq_driver_target+0x27/0x5d
[ 130.032885] [<c1311c69>] cpufreq_cpu_callback+0x47/0x6c
[ 130.040410] [<c1032316>] notifier_call_chain+0x2c/0x39
[ 130.047832] [<c103233f>] raw_notifier_call_chain+0x8/0xa
[ 130.055434] [<c10440a9>] _cpu_down+0x4c/0x219
[ 130.062068] [<c1044483>] disable_nonboot_cpus+0x92/0x14b
[ 130.069682] [<c1049e2a>] enter_state+0x7e/0x1bc
[ 130.076490] [<c104a00b>] state_store+0xa3/0xac
[ 130.083188] [<c10b7110>] subsys_attr_store+0x20/0x25
[ 130.090443] [<c10b743c>] sysfs_write_file+0x8a/0xcb
[ 130.097596] [<c1077bb8>] vfs_write+0xa6/0x170
[ 130.104259] [<c107826c>] sys_write+0x3d/0x64
[ 130.110772] [<c1003173>] syscall_call+0x7/0xb
[ 130.117385] [<b7e63e0e>] 0xb7e63e0e
[ 130.123129] =======================
[ 130.191611] CPU 1 is now offline
[ 130.200482] lockdep: not fixing up alternatives.
[ 130.407367] CPU1 is down
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