I had a similar crash yesterday, although what triggered it was unplugging my phone (Galaxy S3, CDMA US) from a USB port on my laptop. The laptop is a Lenovo W541. The graphics card specs are:

  # lspci | grep VGA
  00:02.0 VGA compatible controller: Intel Corporation 4th Gen Core Processor Integrated Graphics Controller (rev 06)
  01:00.0 VGA compatible controller: NVIDIA Corporation GK107GLM [Quadro K1100M] (rev a1)

The laptop is running Fedora 22.

The relevant lines from "# journalctl -a -e --since=yesterday" are:

  Nov 17 17:15:36 ovce kernel: usb 1-1: USB disconnect, device number 17
  Nov 17 17:15:36 ovce systemd-udevd[849]: error opening USB device 'descriptors' file
  Nov 17 17:15:36 ovce kernel: ata1: exception Emask 0x10 SAct 0x0 SErr 0x4010000 action 0xe frozen
  Nov 17 17:15:36 ovce kernel: ata1: irq_stat 0x00400040, connection status changed
  Nov 17 17:15:36 ovce kernel: ata1: SError: { PHYRdyChg DevExch }
  Nov 17 17:15:36 ovce kernel: ata1: hard resetting link
  Nov 17 17:15:36 ovce kernel: ata6: exception Emask 0x10 SAct 0x0 SErr 0x4010000 action 0xe frozen
  Nov 17 17:15:36 ovce kernel: ata6: irq_stat 0x00400040, connection status changed
  Nov 17 17:15:36 ovce kernel: ata6: SError: { PHYRdyChg DevExch }
  Nov 17 17:15:36 ovce kernel: ata6: hard resetting link
  Nov 17 17:15:37 ovce kernel: nouveau E[Xorg[1535]] nv50cal_space: -16
  Nov 17 17:15:37 ovce kernel: ata6: SATA link up 1.5 Gbps (SStatus 113 SControl 300)
  Nov 17 17:15:37 ovce kernel: ata1: SATA link up 6.0 Gbps (SStatus 133 SControl 300)
  Nov 17 17:15:37 ovce kernel: ata1.00: ACPI cmd ef/02:00:00:00:00:a0 (SET FEATURES) succeeded
  Nov 17 17:15:37 ovce kernel: ata1.00: ACPI cmd f5/00:00:00:00:00:a0 (SECURITY FREEZE LOCK) filtered out
  Nov 17 17:15:37 ovce kernel: ata1.00: ACPI cmd ef/10:03:00:00:00:a0 (SET FEATURES) filtered out
  Nov 17 17:15:37 ovce kernel: ata6.00: ACPI cmd e3/00:1f:00:00:00:a0 (IDLE) succeeded
  Nov 17 17:15:37 ovce kernel: ata6.00: ACPI cmd e3/00:02:00:00:00:a0 (IDLE) succeeded
  Nov 17 17:15:37 ovce kernel: ata6.00: ACPI cmd ef/10:03:00:00:00:a0 (SET FEATURES) filtered out
  Nov 17 17:15:37 ovce kernel: ata1.00: ACPI cmd ef/02:00:00:00:00:a0 (SET FEATURES) succeeded
  Nov 17 17:15:37 ovce kernel: ata1.00: ACPI cmd f5/00:00:00:00:00:a0 (SECURITY FREEZE LOCK) filtered out
  Nov 17 17:15:37 ovce kernel: ata1.00: ACPI cmd ef/10:03:00:00:00:a0 (SET FEATURES) filtered out
  Nov 17 17:15:37 ovce kernel: ata1.00: configured for UDMA/133
  Nov 17 17:15:37 ovce kernel: ata1: EH complete
  Nov 17 17:15:37 ovce kernel: ata6.00: ACPI cmd e3/00:1f:00:00:00:a0 (IDLE) succeeded
  Nov 17 17:15:37 ovce kernel: ata6.00: ACPI cmd e3/00:02:00:00:00:a0 (IDLE) succeeded
  Nov 17 17:15:37 ovce kernel: ata6.00: ACPI cmd ef/10:03:00:00:00:a0 (SET FEATURES) filtered out
  Nov 17 17:15:37 ovce kernel: ata6.00: configured for UDMA/133
  Nov 17 17:15:37 ovce kernel: ata6: EH complete
  Nov 17 17:15:37 ovce kernel: nouveau E[Xorg[1535]] nv50cal_space: -16
    ... 66 identical lines snipped ...
  Nov 17 17:15:37 ovce kernel: nouveau E[Xorg[1535]] nv50cal_space: -16
  Nov 17 17:15:38 ovce kernel: nouveau E[Xorg[1535]] nv50cal_space: -16
    ... 78 identical lines snipped ...
  Nov 17 17:15:38 ovce kernel: nouveau E[Xorg[1535]] nv50cal_space: -16

I haven't tried to reproduce this failure yet because I have to get work done. :(

Similar issue here except that I don't have the nv50cal_space: -16 message and the freeze occurs at random action (last one was when trying to activate VPN in network manager).

I can connect from another computer using SSH:

# dmesg
[ 1197.577285] tun: Universal TUN/TAP device driver, 1.6
[ 1197.577287] tun: (C) 1999-2004 Max Krasnyansky <maxk>
[ 1197.634195] nouveau E[   PFIFO][0000:01:00.0] read fault at 0x0000011000 [UNSUPPORTED_KIND] from PBDMA0/HOST on channel 0x007edbe000 [unknown]


# uname -r
4.2.6-301.fc23.x86_64

NVidia GTX 760

This message is a reminder that Fedora 23 is nearing its end of life.
Approximately 4 (four) weeks from now Fedora will stop maintaining
and issuing updates for Fedora 23. It is Fedora's policy to close all
bug reports from releases that are no longer maintained. At that time
this bug will be closed as EOL if it remains open with a Fedora  'version'
of '23'.

Package Maintainer: If you wish for this bug to remain open because you
plan to fix it in a currently maintained version, simply change the 'version' 
to a later Fedora version.

Thank you for reporting this issue and we are sorry that we were not 
able to fix it before Fedora 23 is end of life. If you would still like 
to see this bug fixed and are able to reproduce it against a later version 
of Fedora, you are encouraged  change the 'version' to a later Fedora 
version prior this bug is closed as described in the policy above.

Although we aim to fix as many bugs as possible during every release's 
lifetime, sometimes those efforts are overtaken by events. Often a 
more recent Fedora release includes newer upstream software that fixes 
bugs or makes them obsolete.

Fedora 23 changed to end-of-life (EOL) status on 2016-12-20. Fedora 23 is
no longer maintained, which means that it will not receive any further
security or bug fix updates. As a result we are closing this bug.

If you can reproduce this bug against a currently maintained version of
Fedora please feel free to reopen this bug against that version. If you
are unable to reopen this bug, please file a new report against the
current release. If you experience problems, please add a comment to this
bug.

Thank you for reporting this bug and we are sorry it could not be fixed.

Probably duplicate of https://bugzilla.redhat.com/show_bug.cgi?id=979659 but still present in Fedora