Issue

• Failed to hot remove PCI card
• Hot remove doesn't complete properly with following error:

        ------------[ cut here ]------------
        WARNING: at kernel/workqueue.c:366 flush_cpu_workqueue+0x8d/0x90() (Not
        tainted)
        Hardware name: BladeSymphony E55A2
        Modules linked in: ipv6 vhost_net macvtap macvlan tun kvm_intel kvm uinput sg
        microcode i2c_i801 i2c_core iTCO_wdt iTCO_vendor_support ioatdma igb(U) dca
        ext4 mbcache jbd2 ata_generic pata_acpi ata_piix sd_mod crc_t10dif dm_mod
        hradrv(U) [last unloaded: scsi_wait_scan]
        Pid: 107, comm: kacpi_notify Not tainted 2.6.32-131.0.15.el6.x86_64 #1
        Call Trace:
        [<ffffffff81067137>] ? warn_slowpath_common+0x87/0xc0
        [<ffffffff81293520>] ? handle_hotplug_event_bridge+0x0/0x4b0
        [<ffffffff8106718a>] ? warn_slowpath_null+0x1a/0x20
        [<ffffffff81088c2d>] ? flush_cpu_workqueue+0x8d/0x90
        [<ffffffff81088cb0>] ? wq_barrier_func+0x0/0x20
        [<ffffffff810894b4>] ? flush_workqueue+0x54/0x80
        [<ffffffff812bc40e>] ? acpi_os_wait_events_complete+0x21/0x23
        [<ffffffff812cd2ef>] ? acpi_remove_notify_handler+0x164/0x21c
        [<ffffffff81291f8f>] ? cleanup_bridge+0x2f/0x1e0
        [<ffffffff812921b2>] ? cleanup_p2p_bridge+0x72/0x80
        [<ffffffff812d8807>] ? acpi_ns_walk_namespace+0xa4/0x115
        [<ffffffff81292140>] ? cleanup_p2p_bridge+0x0/0x80
        [<ffffffff81292140>] ? cleanup_p2p_bridge+0x0/0x80
        [<ffffffff812d664c>] ? acpi_walk_namespace+0x78/0xb2
        [<ffffffff81292170>] ? cleanup_p2p_bridge+0x30/0x80
        [<ffffffff81292a0b>] ? acpiphp_disable_slot+0x5b/0x1c0
        [<ffffffff812937e8>] ? handle_hotplug_event_bridge+0x2c8/0x4b0
        [<ffffffff812bc2e7>] ? acpi_os_signal_semaphore+0x28/0x2c
        [<ffffffff812e106b>] ? acpi_ut_release_mutex+0x63/0x67
        [<ffffffff812bea7f>] ? acpi_bus_get_device+0x2a/0x3d
        [<ffffffff812bc410>] ? acpi_os_execute_deferred+0x0/0x36
        [<ffffffff812ccb72>] ? acpi_ev_notify_dispatch+0x64/0x72
        [<ffffffff812bc439>] ? acpi_os_execute_deferred+0x29/0x36
        [<ffffffff81088830>] ? worker_thread+0x170/0x2a0
        [<ffffffff8108e160>] ? autoremove_wake_function+0x0/0x40
        [<ffffffff810886c0>] ? worker_thread+0x0/0x2a0
        [<ffffffff8108ddf6>] ? kthread+0x96/0xa0
        [<ffffffff8100c1ca>] ? child_rip+0xa/0x20
        [<ffffffff8108dd60>] ? kthread+0x0/0xa0
        [<ffffffff8100c1c0>] ? child_rip+0x0/0x20
        ---[ end trace 6d571c2a3bc7b344 ]---
        INFO: task kacpi_notify:107 blocked for more than 120 seconds.
        "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
        kacpi_notify D 0000000000000000 0 107 2 0x00000000
        ffff88081bd41950 0000000000000046 0000000000000000 ffffffff8108ab58
        0000000000000006 81ddb9401bd41ff0 0000000000000400 0000000100070ea6
        ffff88081bce85f8 ffff88081bd41fd8 000000000000f598 ffff88081bce85f8
        Call Trace:
        [<ffffffff8108ab58>] ? __kernel_text_address+0x58/0x80
        [<ffffffff814dc065>] schedule_timeout+0x215/0x2e0
        [<ffffffff814dbce3>] wait_for_common+0x123/0x180
        [<ffffffff8105dc60>] ? default_wake_function+0x0/0x20
        [<ffffffff81293520>] ? handle_hotplug_event_bridge+0x0/0x4b0
        [<ffffffff814dbdfd>] wait_for_completion+0x1d/0x20
        [<ffffffff81088c01>] flush_cpu_workqueue+0x61/0x90
        [<ffffffff81088cb0>] ? wq_barrier_func+0x0/0x20
        [<ffffffff810894b4>] flush_workqueue+0x54/0x80
        [<ffffffff812bc40e>] acpi_os_wait_events_complete+0x21/0x23
        [<ffffffff812cd2ef>] acpi_remove_notify_handler+0x164/0x21c
        [<ffffffff81291f8f>] cleanup_bridge+0x2f/0x1e0
        [<ffffffff812921b2>] cleanup_p2p_bridge+0x72/0x80
        [<ffffffff812d8807>] acpi_ns_walk_namespace+0xa4/0x115
        [<ffffffff81292140>] ? cleanup_p2p_bridge+0x0/0x80
        [<ffffffff81292140>] ? cleanup_p2p_bridge+0x0/0x80
        [<ffffffff812d664c>] acpi_walk_namespace+0x78/0xb2
        [<ffffffff81292170>] cleanup_p2p_bridge+0x30/0x80
        [<ffffffff81292a0b>] acpiphp_disable_slot+0x5b/0x1c0
        [<ffffffff812937e8>] handle_hotplug_event_bridge+0x2c8/0x4b0
        [<ffffffff812bc2e7>] ? acpi_os_signal_semaphore+0x28/0x2c
        [<ffffffff812e106b>] ? acpi_ut_release_mutex+0x63/0x67
        [<ffffffff812bea7f>] ? acpi_bus_get_device+0x2a/0x3d
        [<ffffffff812bc410>] ? acpi_os_execute_deferred+0x0/0x36
        [<ffffffff812ccb72>] acpi_ev_notify_dispatch+0x64/0x72
        [<ffffffff812bc439>] acpi_os_execute_deferred+0x29/0x36
        [<ffffffff81088830>] worker_thread+0x170/0x2a0
        [<ffffffff8108e160>] ? autoremove_wake_function+0x0/0x40
        [<ffffffff810886c0>] ? worker_thread+0x0/0x2a0
        [<ffffffff8108ddf6>] kthread+0x96/0xa0
        [<ffffffff8100c1ca>] child_rip+0xa/0x20
        [<ffffffff8108dd60>] ? kthread+0x0/0xa0
        [<ffffffff8100c1c0>] ? child_rip+0x0/0x20