Created attachment 107006 [details]
dmesg log

This may not be very useful, but I'm leaving it here just in case. Complete uncut dmesg log attached. Nothing out of the ordinary was found in the X logs.

mesa-10.3.0
kernel-3.16.2
xorg-server-1.16.1

====================

0a:00.0 VGA compatible controller: NVIDIA Corporation G96GL [Quadro FX 580] (rev a1) (prog-if 00 [VGA controller])
        Subsystem: NVIDIA Corporation Device 063a
        Flags: bus master, fast devsel, latency 0, IRQ 90
        Memory at fd000000 (32-bit, non-prefetchable) [size=16M]
        Memory at c0000000 (64-bit, prefetchable) [size=512M]
        Memory at fa000000 (64-bit, non-prefetchable) [size=32M]
        I/O ports at e800 [size=128]
        Expansion ROM at fe980000 [disabled] [size=512K]
        Capabilities: [60] Power Management version 3
        Capabilities: [68] MSI: Enable+ Count=1/1 Maskable- 64bit+
        Capabilities: [78] Express Endpoint, MSI 00
        Capabilities: [b4] Vendor Specific Information: Len=14 <?>
        Capabilities: [100] Virtual Channel
        Capabilities: [128] Power Budgeting <?>
        Capabilities: [600] Vendor Specific Information: ID=0001 Rev=1 Len=024 <?>
        Kernel driver in use: nouveau
        Kernel modules: nouveau, nvidia

====================

Relevant portion of dmesg:

[ 2643.920441] BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
[ 2643.920454] IP: [<ffffffffa017eac6>] nouveau_fence_wait_uevent.isra.3+0x36/0x3e0 [nouveau]
[ 2643.920478] PGD 140a75067 PUD 100702067 PMD 0 
[ 2643.920483] Oops: 0000 [#1] PREEMPT SMP 
[ 2643.920487] Modules linked in: act_police cls_basic cls_flow cls_fw cls_u32 sch_fq_codel sch_tbf sch_prio sch_htb sch_hfsc sch_sfq arptable_filter arp_tables xt_CHECKSUM ipt_rpfilter xt_geoip(O) xt_statistic xt_CT xt_LOG xt_connlimit xt_realm xt_addrtype xt_comment xt_recent ipt_ULOG ipt_MASQUERADE ipt_ECN ipt_CLUSTERIP ipt_ah xt_set nf_nat_tftp nf_nat_snmp_basic nf_conntrack_snmp nf_nat_sip nf_nat_pptp nf_nat_proto_gre nf_nat_irc nf_nat_h323 nf_nat_ftp nf_nat_amanda ts_kmp nf_conntrack_amanda nf_conntrack_sane nf_conntrack_tftp nf_conntrack_sip nf_conntrack_proto_udplite nf_conntrack_proto_sctp nf_conntrack_pptp nf_conntrack_proto_gre nf_conntrack_netlink nf_conntrack_netbios_ns nf_conntrack_broadcast nf_conntrack_irc nf_conntrack_h323 nf_conntrack_ftp xt_TPROXY xt_time xt_TCPMSS xt_tcpmss xt_sctp
[ 2643.920563]  xt_policy xt_pkttype xt_physdev xt_owner xt_NFQUEUE xt_NFLOG xt_multiport xt_mark xt_mac xt_limit xt_length xt_iprange xt_helper xt_hashlimit xt_DSCP xt_dscp xt_dccp xt_conntrack xt_connmark xt_CLASSIFY xt_AUDIT xt_state iptable_raw wacom uas nouveau r8169 ttm drm_kms_helper microcode mii wmi edac_core snd_hda_codec_realtek snd_hda_codec_generic snd_hda_intel snd_hda_controller snd_hda_codec snd_hwdep v4l2loopback(O) snd_aloop
[ 2643.920610] CPU: 5 PID: 439 Comm: X Tainted: G           O  3.16.2-gentoo #1
[ 2643.920614] Hardware name: MSI MS-7640/890FXA-GD70 (MS-7640)  , BIOS V1.8 02/24/2011
[ 2643.920617] task: ffff8801004c6540 ti: ffff88013ece4000 task.ti: ffff88013ece4000
[ 2643.920621] RIP: 0010:[<ffffffffa017eac6>]  [<ffffffffa017eac6>] nouveau_fence_wait_uevent.isra.3+0x36/0x3e0 [nouveau]
[ 2643.920635] RSP: 0018:ffff88013ece7ca8  EFLAGS: 00010282
[ 2643.920638] RAX: 0000000000000000 RBX: ffff88006d3fa068 RCX: 0000000000000000
[ 2643.920641] RDX: 0000000000000001 RSI: 0000000000000001 RDI: ffff88006d3fa068
[ 2643.920644] RBP: ffff88006d3fa070 R08: 0000000000000540 R09: ffff88013ece7ca8
[ 2643.920647] R10: ffffffffa01c72e0 R11: ffff88013ece7e08 R12: 0000000000000001
[ 2643.920651] R13: ffff8801408af9c0 R14: 0000000000000001 R15: 0000000000000001
[ 2643.920654] FS:  00007fa4c6057900(0000) GS:ffff880147d40000(0000) knlGS:0000000000000000
[ 2643.920658] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 2643.920660] CR2: 0000000000000008 CR3: 00000001007aa000 CR4: 00000000000007e0
[ 2643.920663] Stack:
[ 2643.920664]  0000000002162af8 0000000000000540 00000000001e8dbd 0000000000000000
[ 2643.920670]  000000000000000d 0000000000000008 ffff88006d3fa040 0000000000000001
[ 2643.920676]  0000000000000000 ffff8801408af9c0 0000000000000001 0000000000000001
[ 2643.920683] Call Trace:
[ 2643.920698]  [<ffffffffa017f027>] ? nouveau_fence_wait+0x77/0x180 [nouveau]
[ 2643.920705]  [<ffffffffa00bf437>] ? ttm_bo_wait+0xa7/0x1a0 [ttm]
[ 2643.920716]  [<ffffffffa0183b0a>] ? nouveau_gem_object_del+0x4a/0x50 [nouveau]
[ 2643.920727]  [<ffffffffa01855ac>] ? nouveau_gem_ioctl_cpu_prep+0x5c/0xf0 [nouveau]
[ 2643.920733]  [<ffffffff814cf75f>] ? drm_ioctl+0x20f/0x5f0
[ 2643.920744]  [<ffffffffa017c2d6>] ? nouveau_drm_ioctl+0x76/0xa0 [nouveau]
[ 2643.920749]  [<ffffffff811799b7>] ? do_vfs_ioctl+0x2c7/0x490
[ 2643.920753]  [<ffffffff810a25c5>] ? vtime_account_user+0x45/0x60
[ 2643.920757]  [<ffffffff81179c19>] ? SyS_ioctl+0x99/0xb0
[ 2643.920761]  [<ffffffff818b6dec>] ? tracesys+0x7e/0xe2
[ 2643.920765]  [<ffffffff818b6e4b>] ? tracesys+0xdd/0xe2
[ 2643.920768] Code: 6c 24 38 48 89 fb 4c 89 64 24 40 4c 89 6c 24 48 41 89 d4 4c 89 74 24 50 4c 89 7c 24 58 48 89 f5 48 8b 07 49 89 e1 be 01 00 00 00 <48> 8b 50 08 48 8b 8a f0 00 00 00 4c 8b aa 50 07 00 00 48 8b 41 
[ 2643.920816] RIP  [<ffffffffa017eac6>] nouveau_fence_wait_uevent.isra.3+0x36/0x3e0 [nouveau]
[ 2643.920828]  RSP <ffff88013ece7ca8>
[ 2643.920830] CR2: 0000000000000008
[ 2643.925739] ---[ end trace 5129d13251e71ceb ]---