I am having this issue on Xubuntu Xenial with the linux-generic-hwe-16.04-edge kernel. It happened once a long time ago, but now it is happening again. This bug happens when the system is under load and more graphical load is demanded. On my specific case, when my system is already under some load and then I open a software which demands both high video memory (shared memory) and RAM memory, as games can do, then the system freezes. I can see the memory usage increase while the software is loading, until the system completely freezes. To reboot, the two options are a hard reset or SysRq keys. My computer is a Lenovo Ideapad 310, with a Intel Core i3-6100U, with a Intel HD Graphics 520 graphical chip. It has 4 GB of RAM and, when the bug happens, there is always heavy RAM usage. This bug never happened to me without high RAM usage. This bug is not easy to reproduce, but with some tries while the system is under load it is possible to freeze the system. Here is my log. I was watching a video on YouTube while I was chatting in Discord, with Steam opened and was loading the game Robocraft. Basically, heavy load. As the Robocraft loaded, it required both RAM and video memory, which weren't plentiful due to the other software's usage. Then it crashed. Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.020383] BUG: unable to handle kernel NULL pointer dereference at 0000000000000018 Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.020455] IP: gen8_ppgtt_alloc_page_directories.isra.38+0x124/0x270 [i915] Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.021756] PGD 1649d2067 Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.021757] PUD 16c731067 Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.023034] PMD 0 Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.024842] Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.026857] Oops: 0002 [#1] SMP Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.027842] Modules linked in: ccm xt_CHECKSUM iptable_mangle ipt_MASQUERADE nf_nat_masquerade_ipv4 iptable_nat nf_nat_ipv4 bridge stp llc ebtable_filter ebtables rfcomm bnep binfmt_misc nls_iso8859_1 arc4 rtsx_usb_ms memstick uvcvideo videobuf2_vmalloc videobuf2_memops videobuf2_v4l2 videobuf2_core videodev media snd_hda_codec_hdmi snd_hda_codec_conexant snd_hda_codec_generic snd_soc_skl snd_soc_skl_ipc snd_soc_sst_ipc snd_soc_sst_dsp snd_hda_ext_core snd_soc_sst_match snd_soc_core snd_compress ac97_bus snd_pcm_dmaengine snd_hda_intel snd_hda_codec snd_hda_core snd_hwdep intel_rapl x86_pkg_temp_thermal intel_powerclamp coretemp crct10dif_pclmul crc32_pclmul ghash_clmulni_intel pcbc snd_pcm snd_seq_midi snd_seq_midi_event aesni_intel ath10k_pci ath10k_core aes_x86_64 crypto_simd glue_helper ath cryptd Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.033493] snd_rawmidi mac80211 intel_cstate snd_seq snd_seq_device intel_rapl_perf snd_timer cfg80211 joydev input_leds snd serio_raw soundcore shpchp mei_me mei btusb intel_pch_thermal btrtl ucsi hci_uart btbcm btqca ideapad_laptop btintel sparse_keymap bluetooth kvm_intel kvm acpi_pad mac_hid tpm_crb intel_lpss_acpi irqbypass intel_lpss ip6t_REJECT nf_reject_ipv6 nf_log_ipv6 xt_hl ip6t_rt nf_conntrack_ipv6 nf_defrag_ipv6 ipt_REJECT nf_reject_ipv4 nf_log_ipv4 nf_log_common xt_LOG xt_limit xt_tcpudp xt_addrtype nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack ip6table_filter ip6_tables nf_conntrack_netbios_ns nf_conntrack_broadcast nf_nat_ftp nf_nat libcrc32c parport_pc nf_conntrack_ftp nf_conntrack ppdev iptable_filter lp parport ip_tables x_tables autofs4 hid_generic rtsx_usb_sdmmc usbhid rtsx_usb Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.039632] uas usb_storage i915 i2c_algo_bit drm_kms_helper syscopyarea sysfillrect psmouse sysimgblt fb_sys_fops drm ahci r8169 libahci mii wmi i2c_hid hid video pinctrl_sunrisepoint pinctrl_intel fjes Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.042237] CPU: 3 PID: 11048 Comm: opera-developer Not tainted 4.10.0-22-generic #24~16.04.1-Ubuntu Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.043552] Hardware name: LENOVO 80UG/Toronto 4A2, BIOS 0XCN42WW 04/21/2017 Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.044877] task: ffff94bb13bd1700 task.stack: ffffa74ec34e8000 Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.046185] RIP: 0010:gen8_ppgtt_alloc_page_directories.isra.38+0x124/0x270 [i915] Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.047499] RSP: 0018:ffffa74ec34eb878 EFLAGS: 00010246 Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.048905] RAX: ffff94ba258cba00 RBX: 0000000000000003 RCX: 0000000000000003 Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.050207] RDX: 0000000000000000 RSI: ffff94ba42aca000 RDI: ffff94bb25758000 Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.051497] RBP: ffffa74ec34eb8d8 R08: 0000000000000018 R09: 0000000000000000 Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.052771] R10: 0000000000000000 R11: fffff5ef01adb520 R12: ffff94badb87c000 Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.054059] R13: ffff94bb101cbb10 R14: 00000000fffd7000 R15: 0000000000008000 Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.055411] FS: 00007f0ec56e3a80(0000) GS:ffff94bb33580000(0000) knlGS:0000000000000000 Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.056770] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.058415] CR2: 0000000000000018 CR3: 0000000139fdf000 CR4: 00000000003406e0 Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.059691] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.060982] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.062151] Call Trace: Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.063371] gen8_alloc_va_range_3lvl+0xf3/0x9b0 [i915] Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.064607] ? set_next_entity+0xc3/0x1b0 Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.065765] gen8_alloc_va_range+0x23e/0x490 [i915] Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.066941] i915_vma_bind+0x6a/0x170 [i915] Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.068080] __i915_vma_do_pin+0x2a5/0x450 [i915] Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.069223] i915_gem_execbuffer_reserve_vma.isra.31+0x144/0x1b0 [i915] Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.070358] i915_gem_execbuffer_reserve.isra.32+0x388/0x3b0 [i915] Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.071533] i915_gem_do_execbuffer.isra.38+0x4f7/0x1570 [i915] Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.072639] ? krealloc+0x79/0xc0 Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.073726] ? reservation_object_get_fences_rcu+0x94/0x240 Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.074808] ? i915_gem_object_wait_reservation+0x18f/0x1e0 [i915] Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.075896] i915_gem_execbuffer2+0xa2/0x1e0 [i915] Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.076966] drm_ioctl+0x21b/0x4d0 [drm] Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.078026] ? i915_gem_execbuffer+0x310/0x310 [i915] Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.079130] ? __seccomp_filter+0x67/0x250 Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.080191] ? pick_next_task_fair+0x3d6/0x4d0 Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.081248] do_vfs_ioctl+0xa1/0x5f0 Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.082308] ? __secure_computing+0x3b/0xd0 Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.083373] ? syscall_trace_enter+0xcd/0x2f0 Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.084517] SyS_ioctl+0x79/0x90 Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.085526] do_syscall_64+0x5b/0xc0 Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.086514] entry_SYSCALL64_slow_path+0x25/0x25 Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.087473] RIP: 0033:0x7f0ebdd34357 Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.088410] RSP: 002b:00007ffc76da95f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.089323] RAX: ffffffffffffffda RBX: 000016019996b000 RCX: 00007f0ebdd34357 Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.090222] RDX: 00007ffc76da9640 RSI: 0000000040406469 RDI: 0000000000000086 Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.091107] RBP: 00007ffc76da9640 R08: 000016019a7d4c80 R09: 0000000000000000 Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.091946] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000040406469 Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.092750] R13: 0000000000000086 R14: 000016019998a790 R15: 0000000000000050 Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.093518] Code: 20 03 00 00 48 8b b8 d8 02 00 00 48 8b 52 08 48 83 ca 03 e8 1f cd ff ff 48 8b 45 a8 4c 8b 45 c8 48 8b 4d c0 48 8b 10 48 8b 45 d0 <4e> 89 24 02 48 0f ab 08 0f 1f 44 00 00 e9 44 ff ff ff 81 fb 00 Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.095127] RIP: gen8_ppgtt_alloc_page_directories.isra.38+0x124/0x270 [i915] RSP: ffffa74ec34eb878 Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.095907] CR2: 0000000000000018 Jun 9 22:00:54 usuario-Lenovo-ideapad-310-14ISK kernel: [16404.100725] ---[ end trace 3da33a9edc49d9fc ]---