INFO: possible circular locking in the resume

["Zdenek Kabelac" <zdenek.kabelac@gmail.com>]

Hi

I'm getting this INFO: from suspend/resume process.
(Kernel uses patches from this bugzilla to survive suspend
http://bugzilla.kernel.org/show_bug.cgi?id=10030)
(Config is available in the bugzilla)


[   42.097522] MMC: killing requests for dead queue
[   42.098738] PM: Finishing wakeup.
[   42.098740] Restarting tasks ... <6>usb 3-2: USB disconnect, address 2
[   42.129810] done.
[   42.258523]
[   42.258524] =======================================================
[   42.258626] [ INFO: possible circular locking dependency detected ]
[   42.258681] 2.6.25-rc3 #81
[   42.258736] -------------------------------------------------------
[   42.258787] sh/1973 is trying to acquire lock:
[   42.258839]  (&cpu_hotplug.lock){--..}, at: [<ffffffff8106d7a5>]
get_online_cpus+0x35/0x50
[   42.259068]
[   42.259068] but task is already holding lock:
[   42.259166]  (&sp->mutex){--..}, at: [<ffffffff8105adb0>]
synchronize_srcu+0x20/0x90
[   42.259376]
[   42.259377] which lock already depends on the new lock.
[   42.259377]
[   42.259501]
[   42.259501] the existing dependency chain (in reverse order) is:
[   42.259501]
[   42.259501] -> #3 (&sp->mutex){--..}:
[   42.259501]        [<ffffffff81066d30>] __lock_acquire+0xfb0/0x1040
[   42.259501]        [<ffffffff81066e68>] lock_acquire+0xa8/0xf0
[   42.259501]        [<ffffffff812ef5ac>] mutex_lock_nested+0xcc/0x370
[   42.259501]        [<ffffffff8105adb0>] synchronize_srcu+0x20/0x90
[   42.259501]        [<ffffffff8105b2b4>]
srcu_notifier_chain_unregister+0x74/0xe0
[   42.259501]        [<ffffffff8125a337>] cpufreq_unregister_notifier+0x17/0x40
[   42.259501]        [<ffffffff8829e296>]
cpufreq_governor_userspace+0x1b6/0x1f4 [cpufreq_userspace]
[   42.259501]        [<ffffffff81259923>] __cpufreq_governor+0xd3/0x150
[   42.259501]        [<ffffffff8125a0b5>] __cpufreq_set_policy+0x115/0x170
[   42.259501]        [<ffffffff8125a819>] store_scaling_governor+0xc9/0x260
[   42.259501]        [<ffffffff8125b527>] store+0x87/0xa0
[   42.259501]        [<ffffffff811101fa>] sysfs_write_file+0xca/0x140
[   42.259501]        [<ffffffff810bb82b>] vfs_write+0xcb/0x170
[   42.259501]        [<ffffffff810bb9c0>] sys_write+0x50/0x90
[   42.259501]        [<ffffffff8100c70a>] system_call_after_swapgs+0x8a/0x8f
[   42.259501]        [<ffffffffffffffff>] 0xffffffffffffffff
[   42.259501]
[   42.259501] -> #2 (userspace_mutex){--..}:
[   42.259501]        [<ffffffff81066d30>] __lock_acquire+0xfb0/0x1040
[   42.259501]        [<ffffffff81066e68>] lock_acquire+0xa8/0xf0
[   42.259501]        [<ffffffff812ef5ac>] mutex_lock_nested+0xcc/0x370
[   42.259501]        [<ffffffff8829e13c>]
cpufreq_governor_userspace+0x5c/0x1f4 [cpufreq_userspace]
[   42.259501]        [<ffffffff81259923>] __cpufreq_governor+0xd3/0x150
[   42.259501]        [<ffffffff8125a0cb>] __cpufreq_set_policy+0x12b/0x170
[   42.259501]        [<ffffffff8125a819>] store_scaling_governor+0xc9/0x260
[   42.259501]        [<ffffffff8125b527>] store+0x87/0xa0
[   42.259501]        [<ffffffff811101fa>] sysfs_write_file+0xca/0x140
[   42.259501]        [<ffffffff810bb82b>] vfs_write+0xcb/0x170
[   42.259501]        [<ffffffff810bb9c0>] sys_write+0x50/0x90
[   42.259501]        [<ffffffff8100c70a>] system_call_after_swapgs+0x8a/0x8f
[   42.259501]        [<ffffffffffffffff>] 0xffffffffffffffff
[   42.259501]
[   42.259501] -> #1 (&per_cpu(cpu_policy_rwsem, cpu)){----}:
[   42.259501]        [<ffffffff81066d30>] __lock_acquire+0xfb0/0x1040
[   42.259501]        [<ffffffff81066e68>] lock_acquire+0xa8/0xf0
[   42.259501]        [<ffffffff812effc8>] down_write+0x38/0x70
[   42.259501]        [<ffffffff8125ae7c>] lock_policy_rwsem_write+0x4c/0x90
[   42.259501]        [<ffffffff812edbed>] cpufreq_cpu_callback+0x6d/0x90
[   42.259501]        [<ffffffff812f578f>] notifier_call_chain+0x3f/0x80
[   42.259501]        [<ffffffff8105b059>] __raw_notifier_call_chain+0x9/0x10
[   42.259501]        [<ffffffff8106d368>] _cpu_down+0xa8/0x290
[   42.259501]        [<ffffffff8106d621>] disable_nonboot_cpus+0x71/0x110
[   42.259501]        [<ffffffff810730d5>] suspend_devices_and_enter+0xe5/0x1a0
[   42.259501]        [<ffffffff81073306>] enter_state+0x146/0x1d0
[   42.259501]        [<ffffffff8107344a>] state_store+0xba/0x100
[   42.259501]        [<ffffffff811757f7>] kobj_attr_store+0x17/0x20
[   42.259501]        [<ffffffff811101fa>] sysfs_write_file+0xca/0x140
[   42.259501]        [<ffffffff810bb82b>] vfs_write+0xcb/0x170
[   42.259501]        [<ffffffff810bb9c0>] sys_write+0x50/0x90
[   42.259501]        [<ffffffff8100c70a>] system_call_after_swapgs+0x8a/0x8f
[   42.259501]        [<ffffffffffffffff>] 0xffffffffffffffff
[   42.259501]
[   42.259501] -> #0 (&cpu_hotplug.lock){--..}:
[   42.259501]        [<ffffffff81066c3d>] __lock_acquire+0xebd/0x1040
[   42.259501]        [<ffffffff81066e68>] lock_acquire+0xa8/0xf0
[   42.259501]        [<ffffffff812ef5ac>] mutex_lock_nested+0xcc/0x370
[   42.259501]        [<ffffffff8106d7a5>] get_online_cpus+0x35/0x50
[   42.259501]        [<ffffffff8103837e>] sched_getaffinity+0x1e/0xa0
[   42.259501]        [<ffffffff8108b386>] __synchronize_sched+0x16/0x90
[   42.259501]        [<ffffffff8105add5>] synchronize_srcu+0x45/0x90
[   42.259501]        [<ffffffff8105b2b4>]
srcu_notifier_chain_unregister+0x74/0xe0
[   42.259501]        [<ffffffff8125a337>] cpufreq_unregister_notifier+0x17/0x40
[   42.259501]        [<ffffffff8829e296>]
cpufreq_governor_userspace+0x1b6/0x1f4 [cpufreq_userspace]
[   42.259501]        [<ffffffff81259923>] __cpufreq_governor+0xd3/0x150
[   42.259501]        [<ffffffff8125a0b5>] __cpufreq_set_policy+0x115/0x170
[   42.259501]        [<ffffffff8125a819>] store_scaling_governor+0xc9/0x260
[   42.259501]        [<ffffffff8125b527>] store+0x87/0xa0
[   42.259501]        [<ffffffff811101fa>] sysfs_write_file+0xca/0x140
[   42.259501]        [<ffffffff810bb82b>] vfs_write+0xcb/0x170
[   42.259501]        [<ffffffff810bb9c0>] sys_write+0x50/0x90
[   42.259501]        [<ffffffff8100c70a>] system_call_after_swapgs+0x8a/0x8f
[   42.259501]        [<ffffffffffffffff>] 0xffffffffffffffff
[   42.259501]
[   42.259501] other info that might help us debug this:
[   42.259501]
[   42.259501] 4 locks held by sh/1973:
[   42.259501]  #0:  (&buffer->mutex){--..}, at: [<ffffffff81110173>]
sysfs_write_file+0x43/0x140
[   42.259501]  #1:  (&per_cpu(cpu_policy_rwsem, cpu)){----}, at:
[<ffffffff8125ae7c>] lock_policy_rwsem_write+0x4c/0x90
[   42.259501]  #2:  (userspace_mutex){--..}, at: [<ffffffff8829e22e>]
cpufreq_governor_userspace+0x14e/0x1f4 [cpufreq_userspace]
[   42.259501]  #3:  (&sp->mutex){--..}, at: [<ffffffff8105adb0>]
synchronize_srcu+0x20/0x90
[   42.259501]
[   42.259501] stack backtrace:
[   42.259501] Pid: 1973, comm: sh Not tainted 2.6.25-rc3 #81
[   42.259501]
[   42.259501] Call Trace:
[   42.259501]  [<ffffffff81065ac4>] print_circular_bug_tail+0x84/0x90
[   42.259501]  [<ffffffff81065872>] ? print_circular_bug_entry+0x52/0x60
[   42.259501]  [<ffffffff81066c3d>] __lock_acquire+0xebd/0x1040
[   42.259501]  [<ffffffff8106353b>] ? find_usage_backwards+0xcb/0x110
[   42.259502]  [<ffffffff8106353b>] ? find_usage_backwards+0xcb/0x110
[   42.259502]  [<ffffffff8106d7a5>] ? get_online_cpus+0x35/0x50
[   42.259502]  [<ffffffff81066e68>] lock_acquire+0xa8/0xf0
[   42.259502]  [<ffffffff8106d7a5>] ? get_online_cpus+0x35/0x50
[   42.259502]  [<ffffffff812ef5ac>] mutex_lock_nested+0xcc/0x370
[   42.259502]  [<ffffffff8106d7a5>] ? get_online_cpus+0x35/0x50
[   42.259502]  [<ffffffff81065649>] ? trace_hardirqs_on+0x139/0x1a0
[   42.259502]  [<ffffffff8106d7a5>] get_online_cpus+0x35/0x50
[   42.259502]  [<ffffffff8103837e>] sched_getaffinity+0x1e/0xa0
[   42.259502]  [<ffffffff8108b386>] __synchronize_sched+0x16/0x90
[   42.259502]  [<ffffffff8105add5>] synchronize_srcu+0x45/0x90
[   42.259502]  [<ffffffff8105b2b4>] srcu_notifier_chain_unregister+0x74/0xe0
[   42.259502]  [<ffffffff8125a337>] cpufreq_unregister_notifier+0x17/0x40
[   42.259502]  [<ffffffff8829e296>]
:cpufreq_userspace:cpufreq_governor_userspace+0x1b6/0x1f4
[   42.259502]  [<ffffffff81259923>] __cpufreq_governor+0xd3/0x150
[   42.259502]  [<ffffffff8125a0b5>] __cpufreq_set_policy+0x115/0x170
[   42.259502]  [<ffffffff8125a819>] store_scaling_governor+0xc9/0x260
[   42.259502]  [<ffffffff8125b650>] ? handle_update+0x0/0x10
[   42.259502]  [<ffffffff812efff0>] ? down_write+0x60/0x70
[   42.259502]  [<ffffffff8125b527>] store+0x87/0xa0
[   42.259502]  [<ffffffff811101fa>] sysfs_write_file+0xca/0x140
[   42.259502]  [<ffffffff810bb82b>] vfs_write+0xcb/0x170
[   42.259502]  [<ffffffff810bb9c0>] sys_write+0x50/0x90
[   42.259502]  [<ffffffff8100c70a>] system_call_after_swapgs+0x8a/0x8f
[   42.259502]
[   41.439840] mmc0: new SD card at address 5a61
[   41.440027] mmcblk0: mmc0:5a61 S016B 14560KiB
[   41.440123]  mmcblk0: p1
[   41.916006] usb 3-2: new full speed USB device using uhci_hcd and address 3
[   42.900716] usb 3-2: configuration #1 chosen from 1 choice
[   42.080814] usb 3-2: New USB device found, idVendor=0483, idProduct=2016
[   42.080939] usb 3-2: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[   42.081094] usb 3-2: Product: Biometric Coprocessor
[   42.081212] usb 3-2: Manufacturer: STMicroelectronics
[   47.925651] PM: Syncing filesystems ... done.
[   47.925845] PM: Preparing system for mem sleep
[   47.925925] Freezing user space processes ... (elapsed 0.00 seconds) done.
[   47.926302] Freezing remaining freezable tasks ... (elapsed 0.00
seconds) done.
[   47.926596] PM: Entering mem sleep
[   47.929993] ACPI: Preparing to enter system sleep state S3
[   49.169572] sd 0:0:0:0: [sda] Synchronizing SCSI cache
[   49.169771] sd 0:0:0:0: [sda] Stopping disk
[   51.204365] mmc0: card 5a61 removed
[   51.204365] ACPI handle has no context!
[   51.204365] ACPI: PCI interrupt for device 0000:15:00.2 disabled
[   51.204365] ACPI handle has no context!