[Nexus 5 Q&A, Help & Troubleshooting] hellsgod:
[ 5222.373768] msm_pm_enter
[ 5222.373768] msm_pm_enter: power collapse
[ 5222.373768] msm_pm_enter: return
[ 5222.373768] Resume caused by IRQ 200, qcom,smd-rpm
[ 5222.375459] PM: noirq resume of devices complete after 0.985 msecs
[ 5222.375873] Watchdog bite received from modem software!
[ 5222.375888] modem subsystem failure reason: SFR Init: wdog or kernel error suspected..
[ 5222.375898] subsys-restart: subsystem_restart_dev(): Restart sequence requested for modem, restart_level = RELATED.
[ 5222.376635] PM: early resume of devices complete after 0.651 msecs
[ 5222.377470] subsys-restart: subsystem_shutdown(): [c3da1680]: Shutting down modem
[ 5222.445466] PM: resume of devices complete after 68.818 msecs
[ 5222.448679] Restarting tasks ... done.
[ 5222.467449] PM: suspend exit 2014-12-16 21:37:00.346019209 UTC
[ 5222.477500] pil-q6v5-mss fc880000.qcom,mss: Port c7d82180 halt timeout
[ 5222.577667] pil-q6v5-mss fc880000.qcom,mss: Port c7d82200 halt timeout
[ 5222.669191] max17048_work: rsoc=0x82B5 rvcell=0x0C4A soc=67 v_mv=3932 i_ua=196004 t=263
[ 5222.677798] pil-q6v5-mss fc880000.qcom,mss: Port c7d82280 halt timeout
[ 5222.679141] smem_find(22, 40): wrong size 88
[ 5222.679484] smem_find(22, 40): wrong size 88
[ 5222.679930] smd_pkt_read notifying reset for smd_pkt_dev id:7
[ 5222.680578] smd_pkt_read notifying reset for smd_pkt_dev id:6
[ 5222.680698] smd_pkt_read notifying reset for smd_pkt_dev id:5
[ 5222.680864] smd_pkt_read notifying reset for smd_pkt_dev id:4
[ 5222.680977] smd_pkt_read notifying reset for smd_pkt_dev id:3
[ 5222.681141] smd_pkt_read notifying reset for smd_pkt_dev id:2
[ 5222.681255] smd_pkt_read notifying reset for smd_pkt_dev id:1
[ 5222.681422] smd_pkt_read notifying reset for smd_pkt_dev id:0
[ 5222.706883] Ramdump(ramdump_smem): No consumers. Aborting..
[ 5222.707010] restart_notifier_cb: unable to dump smem -32
[ 5222.711564] modem_notifier_cb: sysmon_send_event error -38
[ 5222.711684] M-Notify: General: 4
[ 5223.742073] pil-q6v5-mss fc880000.qcom,mss: PBL boot timed out
[ 5223.742473] pil-q6v5-mss fc880000.qcom,mss: mba: Failed to bring out of reset
[ 5223.742628] subsys-restart: subsystem_ramdump(): modem[c3da1680]: Ramdump failed.
[ 5223.744364] subsys-restart: subsystem_powerup(): [c3da1680]: Powering up modem
[ 5224.754402] pil-q6v5-mss fc880000.qcom,mss: PBL boot timed out
[ 5224.754879] pil-q6v5-mss fc880000.qcom,mss: mba: Failed to bring out of reset
[ 5224.755125] Kernel panic - not syncing: [c3da1680]: Powerup error: modem!
[ 5224.755226] [<c010f240>] (unwind_backtrace) from [<c0aba6b8>] (panic+0xa0/0x218)
[ 5224.755371] [<c0aba6b8>] (panic) from [<c0175898>] (subsystem_restart_wq_func+0x978/0x9ec)
[ 5224.755514] [<c0175898>] (subsystem_restart_wq_func) from [<c01c2f20>] (process_one_work+0x1a0/0x454)
[ 5224.755595] [<c01c2f20>] (process_one_work) from [<c01c36a0>] (worker_thread+0x1ac/0x4f4)
[ 5224.755734] [<c01c36a0>] (worker_thread) from [<c01c9e30>] (kthread+0xe0/0xf4)
[ 5224.755874] [<c01c9e30>] (kthread) from [<c0108a3c>] (kernel_thread_exit+0x0/0x8)
[ 5224.755987] Rebooting in 5 seconds..
[ 5229.757680] Going down for restart now
[ 5229.758481] Calling SCM to disable SPMI PMIC arbiter

No errors detected
Boot info:
Last boot reason: modem_err

Modem / Modem Driver error. Nothing I can do I guess. I haven't touched anything in that matter.

hells