I'm also affected by this bug on Trusty with the latest kernel (3.13.0-53-generic):

[500345.624596] BUG: soft lockup - CPU#0 stuck for 23s! [khugepaged:54]
[500345.630989] Modules linked in: ipt_REJECT btrfs ufs qnx4 hfsplus[500345.636604] BUG: soft lockup - CPU#1 stuck for 23s! [kthreadd:2]
[500345.636605] Modules linked in: ipt_REJECT btrfs ufs qnx4 hfsplus hfs minix ntfs msdos jfs xt_multiport iptable_filter ip_tables x_tables kvm_amd edac_core kvm k10temp edac_mce_amd i2c_piix4 serio_raw shpchp mac_hid nfsd auth_rpcgss nfs_acl nfs lp binfmt_misc lockd sunrpc fscache parport xfs libcrc32c xts gf128mul dm_crypt raid10 raid0 multipath linear raid456 async_memcpy async_raid6_recov async_pq async_xor async_tx xor raid6_pq raid1 pata_acpi hid_generic usbhid hid radeon psmouse i2c_algo_bit ahci ttm libahci drm_kms_helper pata_atiixp mpt2sas drm r8169 raid_class scsi_transport_sas mii wmi
[500345.636627] CPU: 1 PID: 2 Comm: kthreadd Tainted: G      D       3.13.0-53-generic #89-Ubuntu
[500345.636628] Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./M3A785GMH/128M, BIOS P1.40 11/26/2009
[500345.636628] task: ffff880214bd9800 ti: ffff880214458000 task.ti: ffff880214458000
[500345.636629] RIP: 0010:[<ffffffff8172ae05>]  [<ffffffff8172ae05>] _raw_spin_lock+0x35/0x50
[500345.636631] RSP: 0018:ffff8802144599f8  EFLAGS: 00000202
[500345.636632] RAX: 00000000000079f7 RBX: ffffffff8127f5bc RCX: 00000000000087ea
[500345.636632] RDX: 00000000000087ec RSI: 00000000000087ec RDI: ffff8800cdef5c80
[500345.636633] RBP: ffff8802144599f8 R08: 9038000000000000 R09: 0107e5b3481c0000
[500345.636633] R10: feda1a8eb150d207 R11: 00000000000003eb R12: 0000000000000046
[500345.636634] R13: ffffffff8115e67e R14: ffff880214459a20 R15: ffffffffffffffff
[500345.636635] FS:  00007fa8ed61e740(0000) GS:ffff88021fc40000(0000) knlGS:0000000000000000
[500345.636636] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[500345.636636] CR2: 00007f8263077000 CR3: 0000000210041000 CR4: 00000000000007e0
[500345.636637] Stack:
[500345.636637]  ffff880214459a18 ffffffff8127ffb9 ffff880107e5b2a8 ffff880107e5b2a8
[500345.636639]  ffff880214459a30 ffffffff81260091 ffff880107e5b3f8 ffff880214459a50
[500345.636641]  ffffffff8124614a ffff880107e5b2a8 ffff880107e5b3b0 ffff880214459a78
[500345.636642] Call Trace:
[500345.636643]  [<ffffffff8127ffb9>] ext4_es_lru_del+0x29/0x70
[500345.636644]  [<ffffffff81260091>] ext4_clear_inode+0x41/0x90
[500345.636646]  [<ffffffff8124614a>] ext4_evict_inode+0x8a/0x4d0
[500345.636647]  [<ffffffff811d9490>] evict+0xb0/0x1b0
[500345.636649]  [<ffffffff811d95c9>] dispose_list+0x39/0x50
[500345.636651]  [<ffffffff811da4f7>] prune_icache_sb+0x47/0x60
[500345.636652]  [<ffffffff811c1875>] super_cache_scan+0x105/0x170
[500345.636654]  [<ffffffff81161357>] shrink_slab+0x1c7/0x370
[500345.636655]  [<ffffffff8116448d>] do_try_to_free_pages+0x3ed/0x540
[500345.636657]  [<ffffffff811646cc>] try_to_free_pages+0xec/0x180
[500345.636658]  [<ffffffff81159385>] __alloc_pages_nodemask+0x7d5/0xb80
[500345.636660]  [<ffffffff810a7400>] ? load_balance+0x120/0x890
[500345.636662]  [<ffffffff810652e3>] copy_process.part.26+0x143/0x16b0
[500345.636663]  [<ffffffff8109d665>] ? sched_clock_cpu+0xb5/0x100
[500345.636664]  [<ffffffff8108b5e0>] ? kthread_create_on_node+0x1c0/0x1c0
[500345.636666]  [<ffffffff81066a25>] do_fork+0xd5/0x340
[500345.636667]  [<ffffffff81066cb6>] kernel_thread+0x26/0x30
[500345.636668]  [<ffffffff8108c02a>] kthreadd+0x15a/0x1c0
[500345.636670]  [<ffffffff8108bed0>] ? kthread_create_on_cpu+0x60/0x60
[500345.636671]  [<ffffffff81733868>] ret_from_fork+0x58/0x90
[500345.636673]  [<ffffffff8108bed0>] ? kthread_create_on_cpu+0x60/0x60
[500345.636674] Code: 00 00 02 00 f0 0f c1 07 89 c2 c1 ea 10 66 39 c2 75 02 5d c3 83 e2 fe 0f b7 f2 b8 00 80 00 00 eb 0c 0f 1f 44 00 00 f3 90 83 e8 01 <74> 0a 0f b7 0f 66 39 ca 75 f1 5d c3 66 66 66 90 66 66 90 eb da
[500345.648614] BUG: soft lockup - CPU#2 stuck for 23s! [aria2c:11547]
[500345.648614] Modules linked in: ipt_REJECT btrfs ufs qnx4 hfsplus hfs minix ntfs msdos jfs xt_multiport iptable_filter ip_tables x_tables kvm_amd edac_core kvm k10temp edac_mce_amd i2c_piix4 serio_raw shpchp mac_hid nfsd auth_rpcgss nfs_acl nfs lp binfmt_misc lockd sunrpc fscache parport xfs libcrc32c xts gf128mul dm_crypt raid10 raid0 multipath linear raid456 async_memcpy async_raid6_recov async_pq async_xor async_tx xor raid6_pq raid1 pata_acpi hid_generic usbhid hid radeon psmouse i2c_algo_bit ahci ttm libahci drm_kms_helper pata_atiixp mpt2sas drm r8169 raid_class scsi_transport_sas mii wmi
[500345.648637] CPU: 2 PID: 11547 Comm: aria2c Tainted: G      D       3.13.0-53-generic #89-Ubuntu
[500345.648637] Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./M3A785GMH/128M, BIOS P1.40 11/26/2009
[500345.648638] task: ffff8800cfb48000 ti: ffff880214550000 task.ti: ffff880214550000
[500345.648639] RIP: 0010:[<ffffffff8172ae02>]  [<ffffffff8172ae02>] _raw_spin_lock+0x32/0x50
[500345.648640] RSP: 0000:ffff880214551910  EFLAGS: 00000202
[500345.648641] RAX: 0000000000005af7 RBX: ffff88010cbfdec0 RCX: 00000000000087ea
[500345.648642] RDX: 00000000000087ee RSI: 00000000000087ee RDI: ffff8800cdef5c80
[500345.648642] RBP: ffff880214551910 R08: 2038000000000000 R09: 010cbfe0101c0000
[500345.648643] R10: fed540631fdc0407 R11: 00000000000003eb R12: ffff880214551900
[500345.648644] R13: ffff8802145518d0 R14: ffffffff8115e67e R15: ffff880214551938
[500345.648645] FS:  00007f826306c780(0000) GS:ffff88021fc80000(0000) knlGS:0000000000000000
[500345.648645] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[500345.648646] CR2: 00007f8263077000 CR3: 000000021207a000 CR4: 00000000000007e0
[500345.648646] Stack:
[500345.648647]  ffff880214551930 ffffffff8127ffb9 ffff88010cbfdf70 ffff88010cbfdf70
[500345.648649]  ffff880214551948 ffffffff81260091 ffff88010cbfe0c0 ffff880214551968
[500345.648650]  ffffffff8124614a ffff88010cbfdf70 ffff88010cbfe078 ffff880214551990
[500345.648652] Call Trace:
[500345.648652]  [<ffffffff8127ffb9>] ext4_es_lru_del+0x29/0x70
[500345.648654]  [<ffffffff81260091>] ext4_clear_inode+0x41/0x90
[500345.648655]  [<ffffffff8124614a>] ext4_evict_inode+0x8a/0x4d0
[500345.648657]  [<ffffffff811d9490>] evict+0xb0/0x1b0
[500345.648659]  [<ffffffff811d95c9>] dispose_list+0x39/0x50
[500345.648660]  [<ffffffff811da4f7>] prune_icache_sb+0x47/0x60
[500345.648662]  [<ffffffff811c1875>] super_cache_scan+0x105/0x170
[500345.648663]  [<ffffffff81161357>] shrink_slab+0x1c7/0x370
[500345.648665]  [<ffffffff8116448d>] do_try_to_free_pages+0x3ed/0x540
[500345.648666]  [<ffffffff811646cc>] try_to_free_pages+0xec/0x180
[500345.648668]  [<ffffffff81159385>] __alloc_pages_nodemask+0x7d5/0xb80
[500345.648670]  [<ffffffff811cacc1>] ? link_path_walk+0x71/0x870
[500345.648672]  [<ffffffff81199f1a>] alloc_pages_vma+0x9a/0x140
[500345.648673]  [<ffffffff8117a573>] handle_mm_fault+0xb23/0xf10
[500345.648675]  [<ffffffff8117ec47>] ? vma_link+0xb7/0xc0
[500345.648677]  [<ffffffff8172ee74>] __do_page_fault+0x184/0x570
[500345.648678]  [<ffffffff8118161e>] ? do_mmap_pgoff+0x34e/0x3d0
[500345.648680]  [<ffffffff8116bed9>] ? vm_mmap_pgoff+0x99/0xc0
[500345.648682]  [<ffffffff8172f27a>] do_page_fault+0x1a/0x70
[500345.648684]  [<ffffffff8172b6a8>] page_fault+0x28/0x30
[500345.648685] Code: 89 e5 b8 00 00 02 00 f0 0f c1 07 89 c2 c1 ea 10 66 39 c2 75 02 5d c3 83 e2 fe 0f b7 f2 b8 00 80 00 00 eb 0c 0f 1f 44 00 00 f3 90 <83> e8 01 74 0a 0f b7 0f 66 39 ca 75 f1 5d c3 66 66 66 90 66 66
[500345.664626] BUG: soft lockup - CPU#3 stuck for 23s! [/usr/sbin/apach:24138]
[500345.664627] Modules linked in: ipt_REJECT btrfs ufs qnx4 hfsplus hfs minix ntfs msdos jfs xt_multiport iptable_filter ip_tables x_tables kvm_amd edac_core kvm k10temp edac_mce_amd i2c_piix4 serio_raw shpchp mac_hid nfsd auth_rpcgss nfs_acl nfs lp binfmt_misc lockd sunrpc fscache parport xfs libcrc32c xts gf128mul dm_crypt raid10 raid0 multipath linear raid456 async_memcpy async_raid6_recov async_pq async_xor async_tx xor raid6_pq raid1 pata_acpi hid_generic usbhid hid radeon psmouse i2c_algo_bit ahci ttm libahci drm_kms_helper pata_atiixp mpt2sas drm r8169 raid_class scsi_transport_sas mii wmi
[500345.664650] CPU: 3 PID: 24138 Comm: /usr/sbin/apach Tainted: G      D       3.13.0-53-generic #89-Ubuntu
[500345.664650] Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./M3A785GMH/128M, BIOS P1.40 11/26/2009
[500345.664651] task: ffff880036679800 ti: ffff8802122fa000 task.ti: ffff8802122fa000
[500345.664652] RIP: 0010:[<ffffffff8172ae0d>]  [<ffffffff8172ae0d>] _raw_spin_lock+0x3d/0x50
[500345.664654] RSP: 0000:ffff8802122fb910  EFLAGS: 00000216
[500345.664654] RAX: 0000000000006222 RBX: ffff88010a3aea48 RCX: 00000000000087ea
[500345.664655] RDX: 00000000000087f0 RSI: 00000000000087f0 RDI: ffff8800cdef5c80
[500345.664656] RBP: ffff8802122fb910 R08: 3038000000000000 R09: 010a3aeb981c0000
[500345.664656] R10: fed7c556f69ee607 R11: 00000000000003eb R12: ffff8802122fb900
[500345.664657] R13: ffff8802122fb8d0 R14: ffffffff8115e67e R15: ffff8802122fb938
[500345.664658] FS:  00007f3205c76780(0000) GS:ffff88021fcc0000(0000) knlGS:0000000000000000
[500345.664658] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[500345.664659] CR2: 00007f320886d068 CR3: 000000020df5c000 CR4: 00000000000007e0
[500345.664659] Stack:
[500345.664660]  ffff8802122fb930 ffffffff8127ffb9 ffff88010a3aeaf8 ffff88010a3aeaf8
[500345.664662]  ffff8802122fb948 ffffffff81260091 ffff88010a3aec48 ffff8802122fb968
[500345.664663]  ffffffff8124614a ffff88010a3aeaf8 ffff88010a3aec00 ffff8802122fb990
[500345.664665] Call Trace:
[500345.664665]  [<ffffffff8127ffb9>] ext4_es_lru_del+0x29/0x70
[500345.664667]  [<ffffffff81260091>] ext4_clear_inode+0x41/0x90
[500345.664668]  [<ffffffff8124614a>] ext4_evict_inode+0x8a/0x4d0
[500345.664670]  [<ffffffff811d9490>] evict+0xb0/0x1b0
[500345.664672]  [<ffffffff811d95c9>] dispose_list+0x39/0x50
[500345.664673]  [<ffffffff811da4f7>] prune_icache_sb+0x47/0x60
[500345.664675]  [<ffffffff811c1875>] super_cache_scan+0x105/0x170
[500345.664676]  [<ffffffff81161357>] shrink_slab+0x1c7/0x370
[500345.664678]  [<ffffffff8116448d>] do_try_to_free_pages+0x3ed/0x540
[500345.664679]  [<ffffffff811646cc>] try_to_free_pages+0xec/0x180
[500345.664681]  [<ffffffff81159385>] __alloc_pages_nodemask+0x7d5/0xb80
[500345.664683]  [<ffffffff81199f1a>] alloc_pages_vma+0x9a/0x140
[500345.664684]  [<ffffffff8117a573>] handle_mm_fault+0xb23/0xf10
[500345.664686]  [<ffffffff811cdf62>] ? final_putname+0x22/0x50
[500345.664688]  [<ffffffff811ce169>] ? putname+0x29/0x40
[500345.664689]  [<ffffffff811cecbf>] ? user_path_at_empty+0x5f/0x90
[500345.664691]  [<ffffffff8172ee74>] __do_page_fault+0x184/0x570
[500345.664693]  [<ffffffff8120d4f4>] ? locks_free_lock+0x64/0x70
[500345.664695]  [<ffffffff8120fd87>] ? fcntl_setlk+0x57/0x2b0
[500345.664696]  [<ffffffff811c330f>] ? SYSC_newstat+0x2f/0x40
[500345.664698]  [<ffffffff8172f27a>] do_page_fault+0x1a/0x70
[500345.664699]  [<ffffffff811d0440>] ? SyS_fcntl+0x490/0x5d0
[500345.664701]  [<ffffffff8172b6a8>] page_fault+0x28/0x30
[500345.664703] Code: 89 c2 c1 ea 10 66 39 c2 75 02 5d c3 83 e2 fe 0f b7 f2 b8 00 80 00 00 eb 0c 0f 1f 44 00 00 f3 90 83 e8 01 74 0a 0f b7 0f 66 39 ca <75> f1 5d c3 66 66 66 90 66 66 90 eb da 66 0f 1f 44 00 00 66 66

[500346.620516]  hfs minix ntfs msdos jfs xt_multiport iptable_filter ip_tables x_tables kvm_amd edac_core kvm k10temp edac_mce_amd i2c_piix4 serio_raw shpchp mac_hid nfsd auth_rpcgss nfs_acl nfs lp binfmt_misc lockd sunrpc fscache parport xfs libcrc32c xts gf128mul dm_crypt raid10 raid0 multipath linear raid456 async_memcpy async_raid6_recov async_pq async_xor async_tx xor raid6_pq raid1 pata_acpi hid_generic usbhid hid radeon psmouse i2c_algo_bit ahci ttm libahci drm_kms_helper pata_atiixp mpt2sas drm r8169 raid_class scsi_transport_sas mii wmi
[500346.669946] CPU: 0 PID: 54 Comm: khugepaged Tainted: G      D       3.13.0-53-generic #89-Ubuntu
[500346.678820] Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./M3A785GMH/128M, BIOS P1.40 11/26/2009
[500346.688907] task: ffff8802140b6000 ti: ffff88020f478000 task.ti: ffff88020f478000
[500346.696480] RIP: 0010:[<ffffffff8172ae02>]  [<ffffffff8172ae02>] _raw_spin_lock+0x32/0x50
[500346.704754] RSP: 0018:ffff88020f479988  EFLAGS: 00000212
[500346.710149] RAX: 000000000000718c RBX: ffffffff8127f5bc RCX: 00000000000087ea
[500346.717374] RDX: 00000000000087f2 RSI: 00000000000087f2 RDI: ffff8800cdef5c80
[500346.724600] RBP: ffff88020f479988 R08: 1038000000000000 R09: 010a3894881c0000
[500346.731841] R10: fed7c7ae06092207 R11: 00000000000003eb R12: ffff88020f479948
[500346.739075] R13: ffffffff8115e67e R14: ffff88020f4799b0 R15: ffffffffffffffff
[500346.746310] FS:  00007f7634f5e740(0000) GS:ffff88021fc00000(0000) knlGS:0000000000000000
[500346.754497] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[500346.760333] CR2: 00007f0d30afb000 CR3: 00000000cf988000 CR4: 00000000000007f0
[500346.767557] Stack:
[500346.769658]  ffff88020f4799a8 ffffffff8127ffb9 ffff88010a3893e8 ffff88010a3893e8
[500346.777220]  ffff88020f4799c0 ffffffff81260091 ffff88010a389538 ffff88020f4799e0
[500346.784767]  ffffffff8124614a ffff88010a3893e8 ffff88010a3894f0 ffff88020f479a08
[500346.792321] Call Trace:
[500346.794864]  [<ffffffff8127ffb9>] ext4_es_lru_del+0x29/0x70
[500346.800528]  [<ffffffff81260091>] ext4_clear_inode+0x41/0x90
[500346.806278]  [<ffffffff8124614a>] ext4_evict_inode+0x8a/0x4d0
[500346.812115]  [<ffffffff811d9490>] evict+0xb0/0x1b0
[500346.816991]  [<ffffffff811d95c9>] dispose_list+0x39/0x50
[500346.822402]  [<ffffffff811da4f7>] prune_icache_sb+0x47/0x60
[500346.828056]  [<ffffffff811c1875>] super_cache_scan+0x105/0x170
[500346.833972]  [<ffffffff81161357>] shrink_slab+0x1c7/0x370
[500346.839453]  [<ffffffff8116448d>] do_try_to_free_pages+0x3ed/0x540
[500346.845717]  [<ffffffff811646cc>] try_to_free_pages+0xec/0x180
[500346.851640]  [<ffffffff81159385>] __alloc_pages_nodemask+0x7d5/0xb80
[500346.858077]  [<ffffffff811aaf8f>] khugepaged_scan_mm_slot+0x3bf/0xc90
[500346.864608]  [<ffffffff817263bd>] ? schedule_timeout+0x17d/0x2d0
[500346.870706]  [<ffffffff811abaaf>] khugepaged+0x24f/0x460
[500346.876117]  [<ffffffff810ab220>] ? prepare_to_wait_event+0x100/0x100
[500346.882647]  [<ffffffff811ab860>] ? khugepaged_scan_mm_slot+0xc90/0xc90
[500346.889344]  [<ffffffff8108b6b2>] kthread+0xd2/0xf0
[500346.894314]  [<ffffffff8108b5e0>] ? kthread_create_on_node+0x1c0/0x1c0
[500346.900950]  [<ffffffff81733868>] ret_from_fork+0x58/0x90
[500346.906440]  [<ffffffff8108b5e0>] ? kthread_create_on_node+0x1c0/0x1c0
[500346.913048] Code: 89 e5 b8 00 00 02 00 f0 0f c1 07 89 c2 c1 ea 10 66 39 c2 75 02 5d c3 83 e2 fe 0f b7 f2 b8 00 80 00 00 eb 0c 0f 1f 44 00 00 f3 90 <83> e8 01 74 0a 0f b7 0f 66 39 ca 75 f1 5d c3 66 66 66 90 66 66