Comment 0 for bug 1788817

Booting Trusty with kernel 3.13.0-156-generic on a fairly new Intel box results in stuck CPU warnings:

[ 33.551942] BUG: soft lockup - CPU#0 stuck for 23s! [kworker/0:1:1119]
[ 33.558560] Modules linked in: hid_generic ast(+) crct10dif_pclmul syscopyarea crc32_pclmul sysfillrect ghash_clmulni_intel sysimgblt aesni_intel i2c_algo_bit aes_x86_64 lrw ttm gf128mul glue_helper drm_kms_helper ablk_helper usbhid cryptd ahci drm hid libahci wmi
[ 33.583971] CPU: 0 PID: 1119 Comm: kworker/0:1 Not tainted 3.13.0-156-generic #206-Ubuntu
[ 33.592270] Hardware name: Intel Corporation S2600WFT/S2600WFT, BIOS SE5C620.86B.01.00.0294.101220161543 10/12/2016
[ 33.602836] Workqueue: events work_for_cpu_fn
[ 33.607351] task: ffff88084ddbc6b0 ti: ffff88084dd98000 task.ti: ffff88084dd98000
[ 33.614957] RIP: 0010:[<ffffffff81383bb2>] [<ffffffff81383bb2>] ioread32+0x42/0x50
[ 33.622805] RSP: 0018:ffff88084dd99d18 EFLAGS: 00000292
[ 33.628201] RAX: 00000000ffffffff RBX: ffff880851265000 RCX: 00000000000028a6
[ 33.635429] RDX: ffffc90016bd0000 RSI: ffffc90016bd0000 RDI: ffffc90016bd0000
[ 33.642653] RBP: ffff88084dd99d40 R08: 0000000000000092 R09: 000000000000079e
[ 33.649877] R10: ffffffff813df570 R11: ffff88084dd99a46 R12: 0000000016bc0000
[ 33.657104] R13: ffffffffa01b2ab0 R14: ffff88084dd99cc8 R15: 0000000000000000
[ 33.664329] FS: 0000000000000000(0000) GS:ffff88085f200000(0000) knlGS:0000000000000000
[ 33.672541] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 33.678380] CR2: 00007f3613be4000 CR3: 0000000001c0e000 CR4: 0000000000360770
[ 33.685605] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 33.692829] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 33.700052] Stack:
[ 33.702150] ffffffffa01a89e0 ffff880851265000 0000000000000000 0000000000000000
[ 33.709948] ffffffffa01b4100 ffff88084dd99d68 ffffffffa0073e88 ffff880851265000
[ 33.717751] ffff880850dee000 ffff880850dee098 ffff88084dd99db8 ffffffffa0075d92
[ 33.725550] Call Trace:
[ 33.728085] [<ffffffffa01a89e0>] ? ast_driver_load+0x320/0x540 [ast]
[ 33.734634] [<ffffffffa0073e88>] drm_dev_register+0xa8/0x1f0 [drm]
[ 33.741000] [<ffffffffa0075d92>] drm_get_pci_dev+0x92/0x140 [drm]
[ 33.747268] [<ffffffffa01a81e5>] ast_pci_probe+0x15/0x20 [ast]
[ 33.753282] [<ffffffff813b5f5a>] local_pci_probe+0x4a/0xb0
[ 33.758947] [<ffffffff8108746a>] work_for_cpu_fn+0x1a/0x30
[ 33.764613] [<ffffffff8108a5fe>] process_one_work+0x17e/0x480
[ 33.770536] [<ffffffff8108b5ab>] worker_thread+0x29b/0x410
[ 33.776205] [<ffffffff8108b310>] ? rescuer_thread+0x430/0x430
[ 33.782130] [<ffffffff810922cb>] kthread+0xcb/0xf0
[ 33.787101] [<ffffffff81092200>] ? kthread_create_on_node+0x1c0/0x1c0
[ 33.793721] [<ffffffff8174758e>] ret_from_fork+0x6e/0xa0
[ 33.799211] [<ffffffff81092200>] ? kthread_create_on_node+0x1c0/0x1c0
[ 33.805828] Code: 66 0f 1f 84 00 00 00 00 00 55 48 c7 c6 80 57 a9 81 48 89 e5 e8 f0 fe ff ff b8 ff ff ff ff 5d c3 66 0f 1f 84 00 00 00 00 00 8b 07 <c3> 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 48 81 fe ff ff 03 00