Why kacpi_notify and power_saving kernel threads are blocked in Uninterruptible (D) state ?
Issue
- kacpi_notify and power_saving kernel threads in Red Hat Enterprise Linux 6 are blocked in Uninterruptible (D) state:
root 235 0.0 0.0 0 0 ? D Sep22 0:00 [kacpi_notify]
root 8103 0.0 0.0 0 0 ? D Sep24 0:07 [power_saving/0]
root 8104 0.0 0.0 0 0 ? D Sep24 0:07 [power_saving/1]
root 8106 0.0 0.0 0 0 ? D Sep24 0:06 [power_saving/2]
root 8107 0.0 0.0 0 0 ? D Sep24 0:05 [power_saving/3]
root 8108 0.0 0.0 0 0 ? D Sep24 0:05 [power_saving/4]
root 8109 0.0 0.0 0 0 ? D Sep24 0:05 [power_saving/5]
- The following tracebacks are logged in system log file (/var/log/messages):
kernel: INFO: task kacpi_notify:235 blocked for more than 120 seconds.
kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kernel: kacpi_notify D 0000000000000000 0 235 2 0x00000000
kernel: ffff880425407b30 0000000000000046 0000000000000000 ffff880425407af4
kernel: 0000000000000000 ffff88042fc28400 ffff8800283d6680 0000000000000200
kernel: ffff880425bfe638 ffff880425407fd8 000000000000fb88 ffff880425bfe638
kernel: Call Trace:
kernel: [<ffffffff814fe925>] schedule_timeout+0x215/0x2e0
kernel: [<ffffffff812ce8b7>] ? acpi_os_release_object+0xe/0x12
kernel: [<ffffffff814fe5a3>] wait_for_common+0x123/0x180
kernel: [<ffffffff81060250>] ? default_wake_function+0x0/0x20
kernel: [<ffffffff814fe6bd>] wait_for_completion+0x1d/0x20
kernel: [<ffffffff81091dbb>] kthread_stop+0x4b/0xd0
kernel: [<ffffffffa020a42a>] acpi_pad_idle_cpus+0xbc/0xd6 [acpi_pad]
kernel: [<ffffffffa020a70c>] acpi_pad_handle_notify+0x96/0x196 [acpi_pad]
kernel: [<ffffffff810096f0>] ? __switch_to+0xd0/0x320
kernel: [<ffffffff814fdab0>] ? thread_return+0x4e/0x76e
kernel: [<ffffffff812cea7f>] ? acpi_os_execute_deferred+0x0/0x36
kernel: [<ffffffffa020a82a>] acpi_pad_notify+0x1e/0x5b [acpi_pad]
kernel: [<ffffffff812df053>] acpi_ev_notify_dispatch+0x64/0x71
kernel: [<ffffffff812ceaa8>] acpi_os_execute_deferred+0x29/0x36
kernel: [<ffffffff8108c760>] worker_thread+0x170/0x2a0
kernel: [<ffffffff810920d0>] ? autoremove_wake_function+0x0/0x40
kernel: [<ffffffff8108c5f0>] ? worker_thread+0x0/0x2a0
kernel: [<ffffffff81091d66>] kthread+0x96/0xa0
kernel: [<ffffffff8100c14a>] child_rip+0xa/0x20
kernel: [<ffffffff81091cd0>] ? kthread+0x0/0xa0
kernel: [<ffffffff8100c140>] ? child_rip+0x0/0x20
kernel: INFO: task power_saving/0:8103 blocked for more than 120 seconds.
kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kernel: power_saving/ D 000000000000001d 0 8103 2 0x00000080
kernel: ffff880823b3ddc0 0000000000000046 0000000000000000 ffff880823b3dd84
kernel: ffff880400000000 ffff88042fc2be00 ffff880028216680 0000000000000290
kernel: ffff88082462c5f8 ffff880823b3dfd8 000000000000fb88 ffff88082462c5f8
kernel: Call Trace:
kernel: [<ffffffff814ff10e>] __mutex_lock_slowpath+0x13e/0x180
kernel: [<ffffffff81271cd0>] ? alloc_cpumask_var_node+0x90/0x100
kernel: [<ffffffff814fefab>] mutex_lock+0x2b/0x50
kernel: [<ffffffffa020a0ef>] power_saving_thread+0xd4/0x353 [acpi_pad]
kernel: [<ffffffffa020a01b>] ? power_saving_thread+0x0/0x353 [acpi_pad]
kernel: [<ffffffff81091d66>] kthread+0x96/0xa0
kernel: [<ffffffff8100c14a>] child_rip+0xa/0x20
kernel: [<ffffffff81091cd0>] ? kthread+0x0/0xa0
kernel: [<ffffffff8100c140>] ? child_rip+0x0/0x20
kernel: INFO: task power_saving/2:8106 blocked for more than 120 seconds.
kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kernel: power_saving/ D 000000000000001f 0 8106 2 0x00000080
kernel: ffff88082453ddc0 0000000000000046 0000000000000000 ffffffff81161c3c
kernel: ffff880425887500 ffff88042fcb02c0 ffff88082583fe00 ffff88082fc004c0
kernel: ffff880823e9c638 ffff88082453dfd8 000000000000fb88 ffff880823e9c638
kernel: Call Trace:
kernel: [<ffffffff81161c3c>] ? transfer_objects+0x5c/0x80
kernel: [<ffffffff814ff10e>] __mutex_lock_slowpath+0x13e/0x180
kernel: [<ffffffff81271cd0>] ? alloc_cpumask_var_node+0x90/0x100
kernel: [<ffffffff814fefab>] mutex_lock+0x2b/0x50
kernel: [<ffffffffa020a0ef>] power_saving_thread+0xd4/0x353 [acpi_pad]
kernel: [<ffffffffa020a01b>] ? power_saving_thread+0x0/0x353 [acpi_pad]
kernel: [<ffffffff81091d66>] kthread+0x96/0xa0
kernel: [<ffffffff8100c14a>] child_rip+0xa/0x20
kernel: [<ffffffff81091cd0>] ? kthread+0x0/0xa0
kernel: [<ffffffff8100c140>] ? child_rip+0x0/0x20
kernel: INFO: task power_saving/4:8108 blocked for more than 120 seconds.
kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kernel: power_saving/ D 0000000000000000 0 8108 2 0x00000080
kernel: ffff8808239c1dc0 0000000000000046 0000000000000000 ffff8808258590a0
kernel: ffff880425c2eae0 ffff880825858ae0 ffff8808239c1d60 ffffffff810a1507
kernel: ffff880825859098 ffff8808239c1fd8 000000000000fb88 ffff880825859098
kernel: Call Trace:
kernel: [<ffffffff810a1507>] ? tick_broadcast_oneshot_control+0xc7/0x120
kernel: [<ffffffff814ff10e>] __mutex_lock_slowpath+0x13e/0x180
kernel: [<ffffffff81271cd0>] ? alloc_cpumask_var_node+0x90/0x100
kernel: [<ffffffff814fefab>] mutex_lock+0x2b/0x50
kernel: [<ffffffffa020a0ef>] power_saving_thread+0xd4/0x353 [acpi_pad]
kernel: [<ffffffffa020a01b>] ? power_saving_thread+0x0/0x353 [acpi_pad]
kernel: [<ffffffff81091d66>] kthread+0x96/0xa0
kernel: [<ffffffff8100c14a>] child_rip+0xa/0x20
kernel: [<ffffffff81091cd0>] ? kthread+0x0/0xa0
kernel: [<ffffffff8100c140>] ? child_rip+0x0/0x20
Environment
- Red Hat Enterprise Linux 6
- kernel-2.6.32-279.5.2.el6.x86_64
- Dell PowerEdge R420 ( BIOS 1.2.4 )
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