[Kernel-packages] [Bug 1295483] Re: [i915] kernel BUG at /build/buildd/linux-3.13.0/lib/swiotlb.c:456!
[Expired for linux (Ubuntu) because there has been no activity for 60 days.] ** Changed in: linux (Ubuntu) Status: Incomplete = Expired -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1295483 Title: [i915] kernel BUG at /build/buildd/linux-3.13.0/lib/swiotlb.c:456! Status in “linux” package in Ubuntu: Expired Bug description: It looks like Chrome's GPU acceleration is very infrequently capable of taking down the kernel; I've been running it for a number of weeks and only just hit this BUG: Mar 21 14:17:49 RedTail kernel: [58101.987805] [ cut here ] Mar 21 14:17:49 RedTail kernel: [58101.987823] kernel BUG at /build/buildd/linux-3.13.0/lib/swiotlb.c:456! Mar 21 14:17:49 RedTail kernel: [58101.987840] invalid opcode: [#1] SMP Mar 21 14:17:49 RedTail kernel: [58101.987852] Modules linked in: hid_magicmouse hidp hid ufs qnx4 hfsplus hfs minix ntfs msdos jfs xfs ctr ccm xt_conntrack ipt_REJECT overlayfs ip6table_filter ip6_tables ebtable_ nat ebtables xt_CHECKSUM iptable_mangle ipt_MASQUERADE iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack xt_tcpudp bridge stp llc iptable_filter ip_tables x_tables lttng_probe_writeback lttng_probe_workqueue rfcomm bnep lttng_probe_vmscan lttng_probe_udp lttng_probe_timer lttng_probe_sunrpc lttng_probe_statedump lttng_probe_sock lttng_probe_skb lttng_probe_signal lttng_probe_scsi lttng_probe_sche d lttng_probe_rpm lttng_probe_regulator lttng_probe_regmap lttng_probe_rcu lttng_probe_random lttng_probe_printk lttng_probe_power lttng_probe_net lttng_probe_napi lttng_probe_module lttng_probe_kvm_x86_mmu lttng_ probe_kvm_x86 lttng_probe_kvm lttng_probe_kmem lttng_probe_jbd2 lttng_probe_irq lttng_probe_gpio lttng_probe_ext4 lttng_probe_compaction lttng_probe_btrfs lttng_probe_block lttng_probe_asoc lttng_types lttng_ring_ buffer_metadata_mmap_client lttng_ring_buffer_client_mmap_overwrite lttng_ring_buffer_client_mmap_discard lttng_ring_buffer_metadata_client lttng_ring_buffer_client_overwrite binfmt_misc lttng_ring_buffer_client_d iscard lttng_tracer lttng_statedump lttng_ftrace lttng_kprobes lttng_lib_ring_buffer lttng_kretprobes joydev nls_iso8859_1 x86_pkg_temp_thermal intel_powerclamp coretemp arc4 kvm_intel kvm ath9k ath9k_common psmou se ath9k_hw serio_raw snd_hda_codec_via ath snd_hda_codec_hdmi snd_hda_intel mac80211 uvcvideo videobuf2_vmalloc snd_hda_codec videobuf2_memops videobuf2_core lpc_ich snd_hwdep snd_pcm videodev cfg80211 rtsx_pci_m s memstick dm_multipath scsi_dh ath3k btusb snd_page_alloc bluetooth mei_me snd_seq_midi snd_seq_midi_event mei snd_rawmidi snd_seq snd_seq_device snd_timer snd mac_hid soundcore lp parport btrfs xor raid6_pq libc rc32c dm_crypt rtsx_pci_sdmmc i915 crct10dif_pclmul crc32_pclmul ghash_clmulni_intel aesni_intel aes_x86_64 lrw gf128mul glue_helper ablk_helper cryptd i2c_algo_bit drm_kms_helper ahci e1000e libahci drm rtsx_pci ptp pps_core wmi video Mar 21 14:17:49 RedTail kernel: [58101.988405] CPU: 7 PID: 19627 Comm: chrome Not tainted 3.13.0-18-generic #38-Ubuntu Mar 21 14:17:49 RedTail kernel: [58101.988424] Hardware name: System76, Inc. Galago UltraPro/Galago UltraPro, BIOS 4.6.5 07/09/2013 Mar 21 14:17:49 RedTail kernel: [58101.988456] task: 88003e62c7d0 ti: 8802d47c6000 task.ti: 8802d47c6000 Mar 21 14:17:49 RedTail kernel: [58101.988476] RIP: 0010:[8137dc2d] [8137dc2d] swiotlb_tbl_map_single+0x28d/0x2a0 Mar 21 14:17:49 RedTail kernel: [58101.988503] RSP: 0018:8802d47c7a70 EFLAGS: 00010246 Mar 21 14:17:49 RedTail kernel: [58101.988517] RAX: RBX: RCX: Mar 21 14:17:49 RedTail kernel: [58101.988535] RDX: 00058000 RSI: d4abd000 RDI: Mar 21 14:17:49 RedTail kernel: [58101.988553] RBP: 8802d47c7ad0 R08: R09: 880402f726d0 Mar 21 14:17:49 RedTail kernel: [58101.988571] R10: 1ea06000 R11: 0062 R12: 880409239098 Mar 21 14:17:49 RedTail kernel: [58101.988589] R13: 0001 R14: 1600 R15: 0020 Mar 21 14:17:49 RedTail kernel: [58101.988607] FS: 7fa8d07d5a00() GS:88041fbc() knlGS: Mar 21 14:17:49 RedTail kernel: [58101.988627] CS: 0010 DS: ES: CR0: 80050033 Mar 21 14:17:49 RedTail kernel: [58101.988642] CR2: 2f6213eea004 CR3: 000362cb9000 CR4: 001407e0 Mar 21 14:17:49 RedTail kernel: [58101.988660] Stack: Mar 21 14:17:49 RedTail kernel: [58101.988667] 1fa944c0 00058000 88039dff9e40 Mar 21 14:17:49 RedTail kernel: [58101.988691] 880409239098 001a957a Mar 21 14:17:49 RedTail kernel: [58101.988723] 880409239098
[Kernel-packages] [Bug 1295483] Re: [i915] kernel BUG at /build/buildd/linux-3.13.0/lib/swiotlb.c:456!
Would it be possible for you to test the latest upstream kernel? Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest v3.14 kernel[0]. If this bug is fixed in the mainline kernel, please add the following tag 'kernel-fixed-upstream'. If the mainline kernel does not fix this bug, please add the tag: 'kernel-bug-exists-upstream'. If you are unable to test the mainline kernel, for example it will not boot, please add the tag: 'kernel-unable-to-test-upstream'. Once testing of the upstream kernel is complete, please mark this bug as Confirmed. Thanks in advance. [0] http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.14-rc7-trusty/ ** Changed in: linux (Ubuntu) Importance: Undecided = Medium ** Tags added: i915 kernel-da-key -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1295483 Title: [i915] kernel BUG at /build/buildd/linux-3.13.0/lib/swiotlb.c:456! Status in “linux” package in Ubuntu: Incomplete Bug description: It looks like Chrome's GPU acceleration is very infrequently capable of taking down the kernel; I've been running it for a number of weeks and only just hit this BUG: Mar 21 14:17:49 RedTail kernel: [58101.987805] [ cut here ] Mar 21 14:17:49 RedTail kernel: [58101.987823] kernel BUG at /build/buildd/linux-3.13.0/lib/swiotlb.c:456! Mar 21 14:17:49 RedTail kernel: [58101.987840] invalid opcode: [#1] SMP Mar 21 14:17:49 RedTail kernel: [58101.987852] Modules linked in: hid_magicmouse hidp hid ufs qnx4 hfsplus hfs minix ntfs msdos jfs xfs ctr ccm xt_conntrack ipt_REJECT overlayfs ip6table_filter ip6_tables ebtable_ nat ebtables xt_CHECKSUM iptable_mangle ipt_MASQUERADE iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack xt_tcpudp bridge stp llc iptable_filter ip_tables x_tables lttng_probe_writeback lttng_probe_workqueue rfcomm bnep lttng_probe_vmscan lttng_probe_udp lttng_probe_timer lttng_probe_sunrpc lttng_probe_statedump lttng_probe_sock lttng_probe_skb lttng_probe_signal lttng_probe_scsi lttng_probe_sche d lttng_probe_rpm lttng_probe_regulator lttng_probe_regmap lttng_probe_rcu lttng_probe_random lttng_probe_printk lttng_probe_power lttng_probe_net lttng_probe_napi lttng_probe_module lttng_probe_kvm_x86_mmu lttng_ probe_kvm_x86 lttng_probe_kvm lttng_probe_kmem lttng_probe_jbd2 lttng_probe_irq lttng_probe_gpio lttng_probe_ext4 lttng_probe_compaction lttng_probe_btrfs lttng_probe_block lttng_probe_asoc lttng_types lttng_ring_ buffer_metadata_mmap_client lttng_ring_buffer_client_mmap_overwrite lttng_ring_buffer_client_mmap_discard lttng_ring_buffer_metadata_client lttng_ring_buffer_client_overwrite binfmt_misc lttng_ring_buffer_client_d iscard lttng_tracer lttng_statedump lttng_ftrace lttng_kprobes lttng_lib_ring_buffer lttng_kretprobes joydev nls_iso8859_1 x86_pkg_temp_thermal intel_powerclamp coretemp arc4 kvm_intel kvm ath9k ath9k_common psmou se ath9k_hw serio_raw snd_hda_codec_via ath snd_hda_codec_hdmi snd_hda_intel mac80211 uvcvideo videobuf2_vmalloc snd_hda_codec videobuf2_memops videobuf2_core lpc_ich snd_hwdep snd_pcm videodev cfg80211 rtsx_pci_m s memstick dm_multipath scsi_dh ath3k btusb snd_page_alloc bluetooth mei_me snd_seq_midi snd_seq_midi_event mei snd_rawmidi snd_seq snd_seq_device snd_timer snd mac_hid soundcore lp parport btrfs xor raid6_pq libc rc32c dm_crypt rtsx_pci_sdmmc i915 crct10dif_pclmul crc32_pclmul ghash_clmulni_intel aesni_intel aes_x86_64 lrw gf128mul glue_helper ablk_helper cryptd i2c_algo_bit drm_kms_helper ahci e1000e libahci drm rtsx_pci ptp pps_core wmi video Mar 21 14:17:49 RedTail kernel: [58101.988405] CPU: 7 PID: 19627 Comm: chrome Not tainted 3.13.0-18-generic #38-Ubuntu Mar 21 14:17:49 RedTail kernel: [58101.988424] Hardware name: System76, Inc. Galago UltraPro/Galago UltraPro, BIOS 4.6.5 07/09/2013 Mar 21 14:17:49 RedTail kernel: [58101.988456] task: 88003e62c7d0 ti: 8802d47c6000 task.ti: 8802d47c6000 Mar 21 14:17:49 RedTail kernel: [58101.988476] RIP: 0010:[8137dc2d] [8137dc2d] swiotlb_tbl_map_single+0x28d/0x2a0 Mar 21 14:17:49 RedTail kernel: [58101.988503] RSP: 0018:8802d47c7a70 EFLAGS: 00010246 Mar 21 14:17:49 RedTail kernel: [58101.988517] RAX: RBX: RCX: Mar 21 14:17:49 RedTail kernel: [58101.988535] RDX: 00058000 RSI: d4abd000 RDI: Mar 21 14:17:49 RedTail kernel: [58101.988553] RBP: 8802d47c7ad0 R08: R09: 880402f726d0 Mar 21 14:17:49 RedTail kernel: [58101.988571] R10: 1ea06000 R11: 0062 R12: 880409239098 Mar 21 14:17:49 RedTail kernel: [58101.988589] R13: 0001 R14: 1600 R15: 0020 Mar 21 14:17:49 RedTail kernel: [58101.988607] FS: 7fa8d07d5a00()
Re: [Kernel-packages] [Bug 1295483] Re: [i915] kernel BUG at/build/buildd/linux-3.13.0/lib/swiotlb.c:456!
I'm now running the 3.14 rc7 build from there. However, it'll be difficult to tell if this is fixed or not; I've only encountered it once in a couple of weeks' solid use of Chrome. -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1295483 Title: [i915] kernel BUG at /build/buildd/linux-3.13.0/lib/swiotlb.c:456! Status in “linux” package in Ubuntu: Incomplete Bug description: It looks like Chrome's GPU acceleration is very infrequently capable of taking down the kernel; I've been running it for a number of weeks and only just hit this BUG: Mar 21 14:17:49 RedTail kernel: [58101.987805] [ cut here ] Mar 21 14:17:49 RedTail kernel: [58101.987823] kernel BUG at /build/buildd/linux-3.13.0/lib/swiotlb.c:456! Mar 21 14:17:49 RedTail kernel: [58101.987840] invalid opcode: [#1] SMP Mar 21 14:17:49 RedTail kernel: [58101.987852] Modules linked in: hid_magicmouse hidp hid ufs qnx4 hfsplus hfs minix ntfs msdos jfs xfs ctr ccm xt_conntrack ipt_REJECT overlayfs ip6table_filter ip6_tables ebtable_ nat ebtables xt_CHECKSUM iptable_mangle ipt_MASQUERADE iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack xt_tcpudp bridge stp llc iptable_filter ip_tables x_tables lttng_probe_writeback lttng_probe_workqueue rfcomm bnep lttng_probe_vmscan lttng_probe_udp lttng_probe_timer lttng_probe_sunrpc lttng_probe_statedump lttng_probe_sock lttng_probe_skb lttng_probe_signal lttng_probe_scsi lttng_probe_sche d lttng_probe_rpm lttng_probe_regulator lttng_probe_regmap lttng_probe_rcu lttng_probe_random lttng_probe_printk lttng_probe_power lttng_probe_net lttng_probe_napi lttng_probe_module lttng_probe_kvm_x86_mmu lttng_ probe_kvm_x86 lttng_probe_kvm lttng_probe_kmem lttng_probe_jbd2 lttng_probe_irq lttng_probe_gpio lttng_probe_ext4 lttng_probe_compaction lttng_probe_btrfs lttng_probe_block lttng_probe_asoc lttng_types lttng_ring_ buffer_metadata_mmap_client lttng_ring_buffer_client_mmap_overwrite lttng_ring_buffer_client_mmap_discard lttng_ring_buffer_metadata_client lttng_ring_buffer_client_overwrite binfmt_misc lttng_ring_buffer_client_d iscard lttng_tracer lttng_statedump lttng_ftrace lttng_kprobes lttng_lib_ring_buffer lttng_kretprobes joydev nls_iso8859_1 x86_pkg_temp_thermal intel_powerclamp coretemp arc4 kvm_intel kvm ath9k ath9k_common psmou se ath9k_hw serio_raw snd_hda_codec_via ath snd_hda_codec_hdmi snd_hda_intel mac80211 uvcvideo videobuf2_vmalloc snd_hda_codec videobuf2_memops videobuf2_core lpc_ich snd_hwdep snd_pcm videodev cfg80211 rtsx_pci_m s memstick dm_multipath scsi_dh ath3k btusb snd_page_alloc bluetooth mei_me snd_seq_midi snd_seq_midi_event mei snd_rawmidi snd_seq snd_seq_device snd_timer snd mac_hid soundcore lp parport btrfs xor raid6_pq libc rc32c dm_crypt rtsx_pci_sdmmc i915 crct10dif_pclmul crc32_pclmul ghash_clmulni_intel aesni_intel aes_x86_64 lrw gf128mul glue_helper ablk_helper cryptd i2c_algo_bit drm_kms_helper ahci e1000e libahci drm rtsx_pci ptp pps_core wmi video Mar 21 14:17:49 RedTail kernel: [58101.988405] CPU: 7 PID: 19627 Comm: chrome Not tainted 3.13.0-18-generic #38-Ubuntu Mar 21 14:17:49 RedTail kernel: [58101.988424] Hardware name: System76, Inc. Galago UltraPro/Galago UltraPro, BIOS 4.6.5 07/09/2013 Mar 21 14:17:49 RedTail kernel: [58101.988456] task: 88003e62c7d0 ti: 8802d47c6000 task.ti: 8802d47c6000 Mar 21 14:17:49 RedTail kernel: [58101.988476] RIP: 0010:[8137dc2d] [8137dc2d] swiotlb_tbl_map_single+0x28d/0x2a0 Mar 21 14:17:49 RedTail kernel: [58101.988503] RSP: 0018:8802d47c7a70 EFLAGS: 00010246 Mar 21 14:17:49 RedTail kernel: [58101.988517] RAX: RBX: RCX: Mar 21 14:17:49 RedTail kernel: [58101.988535] RDX: 00058000 RSI: d4abd000 RDI: Mar 21 14:17:49 RedTail kernel: [58101.988553] RBP: 8802d47c7ad0 R08: R09: 880402f726d0 Mar 21 14:17:49 RedTail kernel: [58101.988571] R10: 1ea06000 R11: 0062 R12: 880409239098 Mar 21 14:17:49 RedTail kernel: [58101.988589] R13: 0001 R14: 1600 R15: 0020 Mar 21 14:17:49 RedTail kernel: [58101.988607] FS: 7fa8d07d5a00() GS:88041fbc() knlGS: Mar 21 14:17:49 RedTail kernel: [58101.988627] CS: 0010 DS: ES: CR0: 80050033 Mar 21 14:17:49 RedTail kernel: [58101.988642] CR2: 2f6213eea004 CR3: 000362cb9000 CR4: 001407e0 Mar 21 14:17:49 RedTail kernel: [58101.988660] Stack: Mar 21 14:17:49 RedTail kernel: [58101.988667] 1fa944c0 00058000 88039dff9e40 Mar 21 14:17:49 RedTail kernel: [58101.988691] 880409239098 001a957a Mar 21 14:17:49
[Kernel-packages] [Bug 1295483] Re: [i915] kernel BUG at /build/buildd/linux-3.13.0/lib/swiotlb.c:456!
apport information ** Tags added: apport-collected ** Description changed: It looks like Chrome's GPU acceleration is very infrequently capable of taking down the kernel; I've been running it for a number of weeks and only just hit this BUG: Mar 21 14:17:49 RedTail kernel: [58101.987805] [ cut here ] Mar 21 14:17:49 RedTail kernel: [58101.987823] kernel BUG at /build/buildd/linux-3.13.0/lib/swiotlb.c:456! Mar 21 14:17:49 RedTail kernel: [58101.987840] invalid opcode: [#1] SMP Mar 21 14:17:49 RedTail kernel: [58101.987852] Modules linked in: hid_magicmouse hidp hid ufs qnx4 hfsplus hfs minix ntfs msdos jfs xfs ctr ccm xt_conntrack ipt_REJECT overlayfs ip6table_filter ip6_tables ebtable_ nat ebtables xt_CHECKSUM iptable_mangle ipt_MASQUERADE iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack xt_tcpudp bridge stp llc iptable_filter ip_tables x_tables lttng_probe_writeback lttng_probe_workqueue rfcomm bnep lttng_probe_vmscan lttng_probe_udp lttng_probe_timer lttng_probe_sunrpc lttng_probe_statedump lttng_probe_sock lttng_probe_skb lttng_probe_signal lttng_probe_scsi lttng_probe_sche d lttng_probe_rpm lttng_probe_regulator lttng_probe_regmap lttng_probe_rcu lttng_probe_random lttng_probe_printk lttng_probe_power lttng_probe_net lttng_probe_napi lttng_probe_module lttng_probe_kvm_x86_mmu lttng_ probe_kvm_x86 lttng_probe_kvm lttng_probe_kmem lttng_probe_jbd2 lttng_probe_irq lttng_probe_gpio lttng_probe_ext4 lttng_probe_compaction lttng_probe_btrfs lttng_probe_block lttng_probe_asoc lttng_types lttng_ring_ buffer_metadata_mmap_client lttng_ring_buffer_client_mmap_overwrite lttng_ring_buffer_client_mmap_discard lttng_ring_buffer_metadata_client lttng_ring_buffer_client_overwrite binfmt_misc lttng_ring_buffer_client_d iscard lttng_tracer lttng_statedump lttng_ftrace lttng_kprobes lttng_lib_ring_buffer lttng_kretprobes joydev nls_iso8859_1 x86_pkg_temp_thermal intel_powerclamp coretemp arc4 kvm_intel kvm ath9k ath9k_common psmou se ath9k_hw serio_raw snd_hda_codec_via ath snd_hda_codec_hdmi snd_hda_intel mac80211 uvcvideo videobuf2_vmalloc snd_hda_codec videobuf2_memops videobuf2_core lpc_ich snd_hwdep snd_pcm videodev cfg80211 rtsx_pci_m s memstick dm_multipath scsi_dh ath3k btusb snd_page_alloc bluetooth mei_me snd_seq_midi snd_seq_midi_event mei snd_rawmidi snd_seq snd_seq_device snd_timer snd mac_hid soundcore lp parport btrfs xor raid6_pq libc rc32c dm_crypt rtsx_pci_sdmmc i915 crct10dif_pclmul crc32_pclmul ghash_clmulni_intel aesni_intel aes_x86_64 lrw gf128mul glue_helper ablk_helper cryptd i2c_algo_bit drm_kms_helper ahci e1000e libahci drm rtsx_pci ptp pps_core wmi video Mar 21 14:17:49 RedTail kernel: [58101.988405] CPU: 7 PID: 19627 Comm: chrome Not tainted 3.13.0-18-generic #38-Ubuntu Mar 21 14:17:49 RedTail kernel: [58101.988424] Hardware name: System76, Inc. Galago UltraPro/Galago UltraPro, BIOS 4.6.5 07/09/2013 Mar 21 14:17:49 RedTail kernel: [58101.988456] task: 88003e62c7d0 ti: 8802d47c6000 task.ti: 8802d47c6000 Mar 21 14:17:49 RedTail kernel: [58101.988476] RIP: 0010:[8137dc2d] [8137dc2d] swiotlb_tbl_map_single+0x28d/0x2a0 Mar 21 14:17:49 RedTail kernel: [58101.988503] RSP: 0018:8802d47c7a70 EFLAGS: 00010246 Mar 21 14:17:49 RedTail kernel: [58101.988517] RAX: RBX: RCX: Mar 21 14:17:49 RedTail kernel: [58101.988535] RDX: 00058000 RSI: d4abd000 RDI: Mar 21 14:17:49 RedTail kernel: [58101.988553] RBP: 8802d47c7ad0 R08: R09: 880402f726d0 Mar 21 14:17:49 RedTail kernel: [58101.988571] R10: 1ea06000 R11: 0062 R12: 880409239098 Mar 21 14:17:49 RedTail kernel: [58101.988589] R13: 0001 R14: 1600 R15: 0020 Mar 21 14:17:49 RedTail kernel: [58101.988607] FS: 7fa8d07d5a00() GS:88041fbc() knlGS: Mar 21 14:17:49 RedTail kernel: [58101.988627] CS: 0010 DS: ES: CR0: 80050033 Mar 21 14:17:49 RedTail kernel: [58101.988642] CR2: 2f6213eea004 CR3: 000362cb9000 CR4: 001407e0 Mar 21 14:17:49 RedTail kernel: [58101.988660] Stack: Mar 21 14:17:49 RedTail kernel: [58101.988667] 1fa944c0 00058000 88039dff9e40 Mar 21 14:17:49 RedTail kernel: [58101.988691] 880409239098 001a957a Mar 21 14:17:49 RedTail kernel: [58101.988723] 880409239098 0040 1600 88021bf3f800 Mar 21 14:17:49 RedTail kernel: [58101.988759] Call Trace: Mar 21 14:17:49 RedTail kernel: [58101.988777] [8137e5ca] swiotlb_map_sg_attrs+0xba/0x150 Mar 21 14:17:49 RedTail kernel: [58101.988820] [a0186db2] i915_gem_gtt_prepare_object+0x82/0xb0 [i915] Mar 21 14:17:49 RedTail kernel:
