Xorg crashed after 13 days 20 hours and 28 minutes of running. The root cause is unknown to me; I can only trace it back to gnome-session-binary running out of file descriptors and crashing on a SIGSEGV which cascades until a nouveau driver message about receiving a signal occurs. I don't know if it's relevant or not that I was running for about a day with "gconf2:amd64 3.2.6-3ubuntu6" installed and it required a reboot which I had not yet done. Start of crash: Oct 30 22:15:33 lakshmi gnome-session[6021]: gnome-session-binary[6021]: WARNING: Failed to receive system inhibitor fd: dup: Too many open files Oct 30 22:15:33 lakshmi gnome-session-binary[6021]: WARNING: Failed to receive system inhibitor fd: dup: Too many open files Repeats over 6004 times (systemd-journald suppressed excess messages): $ fgrep -c 'lakshmi gnome-session-binary[6021]: WARNING: Failed to receive system inhibitor fd: dup: Too many open files' gui-out-of-filedesc-crash 6004 After that: Oct 30 22:17:20 lakshmi gnome-session[6021]: gnome-session-binary[6021]: WARNING: Failed to receive system inhibitor fd: dup: Too many open files Oct 30 22:17:20 lakshmi gnome-session-binary[6021]: WARNING: Failed to receive system inhibitor fd: dup: Too many open files Oct 30 22:17:30 lakshmi gnome-session-binary[6021]: GLib-GIO-CRITICAL: g_unix_fd_list_get: assertion 'G_IS_UNIX_FD_LIST (list)' failed Oct 30 22:17:30 lakshmi kernel: gnome-session-b[6021]: segfault at 8 ip 000000000041e931 sp 00007ffc731d92e0 error 4 in gnome-session-binary[400 000+43000] Oct 30 22:18:02 lakshmi kernel: gdbus[6030]: segfault at 8 ip 00007f3e970ecc9d sp 00007f3e87ffe900 error 6 in libglib-2.0.so.0.4800.2[7f3e970860 00+10f000] Oct 30 22:18:03 lakshmi gnome-session[6021]: ICE default IO error handler doing an exit(), pid = 6312, errno = 11 ... skip ahead ... appears the driver received a signal, the number of the signal is not clear to me ... by then lightdm had logged me out Oct 30 22:18:15 lakshmi lightdm[5646]: pam_unix(lightdm:session): session closed for user mc Oct 30 22:18:15 lakshmi lightdm[5646]: pam_kwallet(lightdm:session): pam_kwallet: pam_sm_close_session Oct 30 22:18:15 lakshmi lightdm[5646]: pam_kwallet5(lightdm:session): pam_kwallet5: pam_sm_close_session Oct 30 22:18:15 lakshmi lightdm[5646]: pam_kwallet(lightdm:setcred): pam_kwallet: pam_sm_setcred Oct 30 22:18:15 lakshmi lightdm[5646]: pam_kwallet5(lightdm:setcred): pam_kwallet5: pam_sm_setcred Oct 30 22:18:15 lakshmi pulseaudio[18405]: [pulseaudio] server-lookup.c: Unable to contact D-Bus: org.freedesktop.DBus.Error.NoServer: Failed to connect to socket /tmp/dbus-2MCP3ISjlb: Connection refused Oct 30 22:18:15 lakshmi pulseaudio[18405]: [pulseaudio] main.c: Unable to contact D-Bus: org.freedesktop.DBus.Error.NoServer: Failed to connect to socket /tmp/dbus-2MCP3ISjlb: Connection refused Oct 30 22:18:16 lakshmi pulseaudio[18405]: [pulseaudio] backend-ofono.c: Failed to register as a handsfree audio agent with ofono: org.freedesktop.DBus.Error.ServiceUnknown: The name org.ofono was not provided by any .service files Oct 30 22:18:17 lakshmi kernel: ------------[ cut here ]------------ Oct 30 22:18:17 lakshmi kernel: WARNING: CPU: 4 PID: 5590 at /build/linux-hwe-IJy1zi/linux-hwe-4.10.0/drivers/gpu/drm/nouveau/nouveau_bo.c:137 nouveau_bo_del_ttm+0x7f/0x90 [nouveau] Oct 30 22:18:17 lakshmi kernel: Modules linked in: isofs cfg80211 ufs qnx4 hfsplus hfs minix ntfs msdos jfs snd_seq_dummy uas usb_storage vhost_net vhost macvtap macvlan xt_CHECKSUM iptable_mangle ipt_MASQUERADE nf_nat_masquerade_ipv4 iptable_nat nf_nat_ipv4 nf_nat nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack nf_conntrack ipt_REJECT nf_reject_ipv4 xt_tcpudp ebtable_filter ebtables ip6table_filter ip6_tables iptable_filter ip_tables x_tables bnep nfnetlink_queue nfnetlink_log nfnetlink bluetooth bridge stp llc binfmt_misc snd_hda_codec_hdmi snd_hda_codec_realtek snd_hda_codec_generic snd_hda_intel snd_hda_codec snd_hda_core snd_hwdep snd_pcm snd_seq_midi snd_seq_midi_event snd_rawmidi snd_seq snd_seq_device edac_mce_amd joydev input_leds edac_core kvm_amd snd_timer kvm snd soundcore irqbypass shpchp asus_atk0110 k10temp Oct 30 22:18:17 lakshmi kernel: serio_raw i2c_piix4 mac_hid parport_pc ppdev lp parport autofs4 xfs btrfs raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c raid0 multipath linear raid1 pata_acpi hid_generic nouveau mxm_wmi usbhid video hid i2c_algo_bit ttm drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops e1000e firewire_ohci r8169 firewire_core psmouse ahci ptp mii crc_itu_t pata_atiixp libahci pata_jmicron drm pps_core fjes wmi Oct 30 22:18:17 lakshmi kernel: CPU: 4 PID: 5590 Comm: Xorg Tainted: G W 4.10.0-37-generic #41~16.04.1-Ubuntu Oct 30 22:18:17 lakshmi kernel: Hardware name: System manufacturer System Product Name/M4A89GTD-PRO/USB3, BIOS 3029 07/05/2012 Oct 30 22:18:17 lakshmi kernel: Call Trace: Oct 30 22:18:17 lakshmi kernel: dump_stack+0x63/0x90 Oct 30 22:18:17 lakshmi kernel: __warn+0xcb/0xf0 Oct 30 22:18:17 lakshmi kernel: warn_slowpath_null+0x1d/0x20 Oct 30 22:18:17 lakshmi kernel: nouveau_bo_del_ttm+0x7f/0x90 [nouveau] Oct 30 22:18:17 lakshmi kernel: ttm_bo_release_list+0xb5/0x170 [ttm] Oct 30 22:18:17 lakshmi kernel: ttm_bo_release+0x1ae/0x240 [ttm] Oct 30 22:18:17 lakshmi kernel: ttm_bo_unref+0x24/0x30 [ttm] Oct 30 22:18:17 lakshmi kernel: nouveau_gem_object_del+0x9a/0xf0 [nouveau] Oct 30 22:18:17 lakshmi kernel: drm_gem_object_free+0x29/0x70 [drm] Oct 30 22:18:17 lakshmi kernel: drm_gem_object_unreference_unlocked+0x3a/0xa0 [drm] Oct 30 22:18:17 lakshmi kernel: drm_gem_object_handle_unreference_unlocked+0x65/0xb0 [drm] Oct 30 22:18:17 lakshmi kernel: drm_gem_object_release_handle+0x53/0x90 [drm] Oct 30 22:18:17 lakshmi kernel: idr_for_each+0xac/0x110 Oct 30 22:18:17 lakshmi kernel: ? drm_gem_object_handle_unreference_unlocked+0xb0/0xb0 [drm] Oct 30 22:18:17 lakshmi kernel: ? drm_fb_release+0x116/0x140 [drm] Oct 30 22:18:17 lakshmi kernel: drm_gem_release+0x20/0x30 [drm] Oct 30 22:18:17 lakshmi kernel: drm_release+0x30b/0x360 [drm] Oct 30 22:18:17 lakshmi kernel: __fput+0xe7/0x220 Oct 30 22:18:17 lakshmi kernel: ____fput+0xe/0x10 Oct 30 22:18:17 lakshmi kernel: task_work_run+0x7e/0xa0 Oct 30 22:18:17 lakshmi kernel: do_exit+0x2c8/0xb40 Oct 30 22:18:17 lakshmi kernel: do_group_exit+0x43/0xb0 Oct 30 22:18:17 lakshmi kernel: get_signal+0x293/0x620 Oct 30 22:18:17 lakshmi kernel: ? __send_signal+0x1cd/0x450 Oct 30 22:18:17 lakshmi kernel: do_signal+0x37/0x750 Oct 30 22:18:17 lakshmi kernel: ? do_send_sig_info+0x6c/0xa0 Oct 30 22:18:17 lakshmi kernel: exit_to_usermode_loop+0x76/0xb0 Oct 30 22:18:17 lakshmi kernel: syscall_return_slowpath+0x59/0x60 Oct 30 22:18:17 lakshmi kernel: entry_SYSCALL_64_fastpath+0xab/0xad Oct 30 22:18:17 lakshmi kernel: RIP: 0033:0x7f1168717428 Oct 30 22:18:17 lakshmi kernel: RSP: 002b:00007ffe63b84f68 EFLAGS: 00000202 ORIG_RAX: 00000000000000ea Oct 30 22:18:17 lakshmi kernel: RAX: 0000000000000000 RBX: 00007f116ae51000 RCX: 00007f1168717428 Oct 30 22:18:17 lakshmi kernel: RDX: 0000000000000006 RSI: 00000000000015d6 RDI: 00000000000015d6 Oct 30 22:18:17 lakshmi kernel: RBP: 00007f11641e3033 R08: 000055dd946dc700 R09: fefefefefeff0900 Oct 30 22:18:17 lakshmi kernel: R10: 0000000000000008 R11: 0000000000000202 R12: 000000000000007a Oct 30 22:18:17 lakshmi kernel: R13: 00007f11641e3940 R14: 000055dd8e0eb588 R15: 000055dd8e0d0bf8 Oct 30 22:18:17 lakshmi kernel: ---[ end trace 29b018f16aa77aab ]---