Module fails to load on IBT-enabled kernels (e.g. Arch Linux with kernel>=5.18)

justmoon commented 2 years ago

Apparently Intel Indirect Branch Tracking feature was enabled in kernel 5.18 for Intel 11th and 12th gen processors and newer. This makes v4l2loopback not load correctly with error:

kernel: traps: Missing ENDBR: init_module+0x0/0x1000 [v4l2loopback]

Full kernel log (dmesg)

Jun 02 07:03:06.069090 perdix kernel: v4l2loopback: loading out-of-tree module taints kernel.
Jun 02 07:03:06.069161 perdix kernel: v4l2loopback: module verification failed: signature and/or required key missing - tainting kernel
Jun 02 07:03:06.069175 perdix kernel: traps: Missing ENDBR: init_module+0x0/0x1000 [v4l2loopback]
Jun 02 07:03:06.069188 perdix kernel: ------------[ cut here ]------------
Jun 02 07:03:06.069415 perdix kernel: kernel BUG at arch/x86/kernel/traps.c:252!
Jun 02 07:03:06.069494 perdix kernel: invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
Jun 02 07:03:06.083762 perdix kernel: CPU: 0 PID: 1604 Comm: modprobe Tainted: G           OE     5.18.1-arch1-1 #1 aeb6a372044721fe869dfc17901d8ed9fc452f1a
Jun 02 07:03:06.083811 perdix kernel: Hardware name: Framework Laptop/FRANBMCP08, BIOS 03.02 07/01/2021
Jun 02 07:03:06.083830 perdix kernel: RIP: 0010:exc_control_protection+0xc2/0xd0
Jun 02 07:03:06.083843 perdix kernel: Code: 8b 93 80 00 00 00 be f9 00 00 00 48 c7 c7 83 ab e6 ab e8 d1 f1 4f ff e9 72 ff ff ff 48 c7 c7 6a ab e6 ab e8 c7 21 fb ff 0f 0b <0f> 0b 66 66 2e 0f 1f 84 0>
Jun 02 07:03:06.083977 perdix kernel: RSP: 0018:ffffb9f4c2443cf8 EFLAGS: 00010002
Jun 02 07:03:06.083992 perdix kernel: RAX: 000000000000003b RBX: ffffb9f4c2443d18 RCX: 0000000000000027
Jun 02 07:03:06.084005 perdix kernel: RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff9fe06fa216a0
Jun 02 07:03:06.084015 perdix kernel: RBP: 0000000000000003 R08: 0000000000000000 R09: ffffb9f4c2443b18
Jun 02 07:03:06.084025 perdix kernel: R10: 0000000000000003 R11: ffffffffac6caa08 R12: 0000000000000000
Jun 02 07:03:06.084040 perdix kernel: R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
Jun 02 07:03:06.084051 perdix kernel: FS:  00007f0a00827740(0000) GS:ffff9fe06fa00000(0000) knlGS:0000000000000000
Jun 02 07:03:06.084063 perdix kernel: CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
Jun 02 07:03:06.084077 perdix kernel: CR2: 00007f0a00239000 CR3: 0000000600dc8001 CR4: 0000000000f70ef0
Jun 02 07:03:06.084087 perdix kernel: PKRU: 55555554
Jun 02 07:03:06.084098 perdix kernel: Call Trace:
Jun 02 07:03:06.084107 perdix kernel:  
Jun 02 07:03:06.084117 perdix kernel:  asm_exc_control_protection+0x22/0x30
Jun 02 07:03:06.084128 perdix kernel: RIP: 0010:init_module+0x0/0x1000 [v4l2loopback]
Jun 02 07:03:06.084138 perdix kernel: Code: Unable to access opcode bytes at RIP 0xffffffffc09f3fd6.
Jun 02 07:03:06.084148 perdix kernel: RSP: 0018:ffffb9f4c2443dc0 EFLAGS: 00010246
Jun 02 07:03:06.084158 perdix kernel: RAX: 0000000000000000 RBX: ffffffffc09f4000 RCX: 0000000000000000
Jun 02 07:03:06.084170 perdix kernel: RDX: 0000000000000000 RSI: ffffffffc09f4000 RDI: ffffb9f4c2443da8
Jun 02 07:03:06.084180 perdix kernel: RBP: ffffb9f4c2443dc8 R08: 0000000000000010 R09: ffff9fd5f07152c0
Jun 02 07:03:06.084190 perdix kernel: R10: ffff9fd5fecd6b80 R11: 0000000000000100 R12: 0000000000000000
Jun 02 07:03:06.084201 perdix kernel: R13: 00007f09fff0bb50 R14: 00005625081d8c20 R15: ffffb9f4c2443e60
Jun 02 07:03:06.084210 perdix kernel:  ? 0xffffffffc09f4000
Jun 02 07:03:06.084219 perdix kernel:  ? 0xffffffffc09f4000
Jun 02 07:03:06.084227 perdix kernel:  do_one_initcall+0x5a/0x220
Jun 02 07:03:06.084238 perdix kernel:  do_init_module+0x4a/0x240
Jun 02 07:03:06.084252 perdix kernel:  __do_sys_init_module+0x138/0x1b0
Jun 02 07:03:06.084261 perdix kernel:  do_syscall_64+0x5c/0x90
Jun 02 07:03:06.084292 perdix kernel:  ? exc_page_fault+0x74/0x170
Jun 02 07:03:06.084310 perdix kernel:  entry_SYSCALL_64_after_hwframe+0x44/0xae
Jun 02 07:03:06.084322 perdix kernel: RIP: 0033:0x7f0a00112c3e
Jun 02 07:03:06.084337 perdix kernel: Code: 48 8b 0d 5d b1 0e 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 49 89 ca b8 af 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c>
Jun 02 07:03:06.084347 perdix kernel: RSP: 002b:00007ffec61e0c98 EFLAGS: 00000246 ORIG_RAX: 00000000000000af
Jun 02 07:03:06.084357 perdix kernel: RAX: ffffffffffffffda RBX: 00005625081d8ce0 RCX: 00007f0a00112c3e
Jun 02 07:03:06.084369 perdix kernel: RDX: 00005625081d8c20 RSI: 0000000000028b40 RDI: 00007f09ffee3010
Jun 02 07:03:06.084378 perdix kernel: RBP: 00007f09ffee3010 R08: 0000000000049000 R09: 0000000000000000
Jun 02 07:03:06.084387 perdix kernel: R10: 0000000000004681 R11: 0000000000000246 R12: 00005625081d8c20
Jun 02 07:03:06.084398 perdix kernel: R13: 00005625081d8e10 R14: 00005625081d8ce0 R15: 00005625081d9410
Jun 02 07:03:06.084407 perdix kernel:  
Jun 02 07:03:06.084438 perdix kernel: Modules linked in: v4l2loopback(OE+) ccm rfcomm snd_seq_dummy snd_hrtimer snd_seq snd_seq_device xt_CHECKSUM xt_MASQUERADE xt_conntrack ipt_REJECT nf_reject_ip>
Jun 02 07:03:06.084497 perdix kernel:  x86_pkg_temp_thermal ledtrig_audio ee1004 iTCO_vendor_support hid_multitouch joydev snd_hda_intel intel_powerclamp coretemp mac80211 snd_intel_dspcfg snd_inte>
Jun 02 07:03:06.084521 perdix kernel:  video acpi_pad int3400_thermal acpi_thermal_rel vfat fat dm_multipath ipmi_devintf ipmi_msghandler sg crypto_user fuse ip_tables x_tables ext4 crc32c_generic >
Jun 02 07:03:06.084533 perdix kernel: ---[ end trace 0000000000000000 ]---
Jun 02 07:03:06.084546 perdix kernel: RIP: 0010:exc_control_protection+0xc2/0xd0
Jun 02 07:03:06.084553 perdix kernel: Code: 8b 93 80 00 00 00 be f9 00 00 00 48 c7 c7 83 ab e6 ab e8 d1 f1 4f ff e9 72 ff ff ff 48 c7 c7 6a ab e6 ab e8 c7 21 fb ff 0f 0b <0f> 0b 66 66 2e 0f 1f 84 0>
Jun 02 07:03:06.084563 perdix kernel: RSP: 0018:ffffb9f4c2443cf8 EFLAGS: 00010002
Jun 02 07:03:06.084572 perdix kernel: RAX: 000000000000003b RBX: ffffb9f4c2443d18 RCX: 0000000000000027
Jun 02 07:03:06.084582 perdix kernel: RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff9fe06fa216a0
Jun 02 07:03:06.084590 perdix kernel: RBP: 0000000000000003 R08: 0000000000000000 R09: ffffb9f4c2443b18
Jun 02 07:03:06.084597 perdix kernel: R10: 0000000000000003 R11: ffffffffac6caa08 R12: 0000000000000000
Jun 02 07:03:06.084604 perdix kernel: R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
Jun 02 07:03:06.084611 perdix kernel: FS:  00007f0a00827740(0000) GS:ffff9fe06fa00000(0000) knlGS:0000000000000000
Jun 02 07:03:06.084619 perdix kernel: CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
Jun 02 07:03:06.084628 perdix kernel: CR2: ffffffffc09f3fd6 CR3: 0000000600dc8001 CR4: 0000000000f70ef0
Jun 02 07:03:06.084637 perdix kernel: PKRU: 55555554

The workaround is to disable IBT with the ibt=off kernel parameter.

See: https://bbs.archlinux.org/viewtopic.php?id=276822

v4l2loopback version: 0.12.5
kernel version: 5.18.1-arch1-1
Distribution: Arch Linux

Steps to reproduce:

Have an Intel 11th or 12th gen processor
Install kernel 5.18 with IBT enabled (default)
Run modprobe v4l2loopback

Observed Results:

v4l2loopback module is added to kernel, but OBS is not able to create a virtual webcam
Kernel log shows kernel: traps: Missing ENDBR: init_module+0x0/0x1000 [v4l2loopback]

Expected Results:

v4l2loopback should load successfully and operate normally
No kernel bug is logged

pswiatki commented 2 years ago

Just in case it could help:

Jun 05 09:41:15 sdr-aptv kernel: traps: Missing ENDBR: init_module+0x0/0x1000 [v4l2loopback]
Jun 05 09:41:15 sdr-aptv kernel: ------------[ cut here ]------------
Jun 05 09:41:15 sdr-aptv kernel: kernel BUG at arch/x86/kernel/traps.c:252!
Jun 05 09:41:15 sdr-aptv kernel: invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
Jun 05 09:41:15 sdr-aptv kernel: CPU: 3 PID: 2310 Comm: modprobe Tainted: G           OE     5.18.1-arch1-1 #1 aeb6a372044721fe869dfc17901d8ed9fc452f1a
Jun 05 09:41:15 sdr-aptv kernel: Hardware name: Dell Inc. Precision 3561/03G764, BIOS 1.8.0 12/10/2021
Jun 05 09:41:15 sdr-aptv kernel: RIP: 0010:exc_control_protection+0xc2/0xd0
Jun 05 09:41:15 sdr-aptv kernel: Code: 8b 93 80 00 00 00 be f9 00 00 00 48 c7 c7 83 ab c6 8e e8 d1 f1 4f ff e9 72 ff ff ff 48 c7 c7 6a ab c6 8e e8 c7 21 fb ff 0f 0b <0f> 0b 66 66 2e 0f 1f 84 00 00 00 00 00 90 66 0f 1f 00 55 53 48 89
Jun 05 09:41:15 sdr-aptv kernel: RSP: 0018:ffffabf1c3b4fc58 EFLAGS: 00010002
Jun 05 09:41:15 sdr-aptv kernel: RAX: 000000000000003b RBX: ffffabf1c3b4fc78 RCX: 0000000000000000
Jun 05 09:41:15 sdr-aptv kernel: RDX: 0000000000000000 RSI: ffff91b54f4e16a0 RDI: ffff91b54f4e16a0
Jun 05 09:41:15 sdr-aptv kernel: RBP: 0000000000000003 R08: 0000000000000000 R09: ffffabf1c3b4fa78
Jun 05 09:41:15 sdr-aptv kernel: R10: 0000000000000003 R11: ffffffff8f4caa08 R12: 0000000000000000
Jun 05 09:41:15 sdr-aptv kernel: R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
Jun 05 09:41:15 sdr-aptv kernel: FS:  00007f862b8e4740(0000) GS:ffff91b54f4c0000(0000) knlGS:0000000000000000
Jun 05 09:41:15 sdr-aptv kernel: CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
Jun 05 09:41:15 sdr-aptv kernel: CR2: 00007f862b039000 CR3: 0000000116aae001 CR4: 0000000000f70ee0
Jun 05 09:41:15 sdr-aptv kernel: PKRU: 55555554
Jun 05 09:41:15 sdr-aptv kernel: Call Trace:
Jun 05 09:41:15 sdr-aptv kernel:  <TASK>
Jun 05 09:41:15 sdr-aptv kernel:  asm_exc_control_protection+0x22/0x30
Jun 05 09:41:15 sdr-aptv kernel: RIP: 0010:init_module+0x0/0x1000 [v4l2loopback]
Jun 05 09:41:15 sdr-aptv kernel: Code: Unable to access opcode bytes at RIP 0xffffffffc09d6fd6.
Jun 05 09:41:15 sdr-aptv kernel: RSP: 0018:ffffabf1c3b4fd28 EFLAGS: 00010246
Jun 05 09:41:15 sdr-aptv kernel: RAX: 0000000000000000 RBX: ffffffffc09d7000 RCX: 0000000000000000
Jun 05 09:41:15 sdr-aptv kernel: RDX: 0000000000000000 RSI: ffffffffc09d7000 RDI: ffffabf1c3b4fd10
Jun 05 09:41:15 sdr-aptv kernel: RBP: ffffabf1c3b4fd30 R08: 0000000000000010 R09: ffff91a664e7ab10
Jun 05 09:41:15 sdr-aptv kernel: R10: ffff91a632765940 R11: 0000000000000100 R12: 0000000000000000
Jun 05 09:41:15 sdr-aptv kernel: R13: 00007f862afd8b50 R14: 00005570e42d6d70 R15: ffffabf1c3b4fdc8
Jun 05 09:41:15 sdr-aptv kernel:  ? 0xffffffffc09d7000
Jun 05 09:41:15 sdr-aptv kernel:  ? 0xffffffffc09d7000
Jun 05 09:41:15 sdr-aptv kernel:  do_one_initcall+0x5a/0x220
Jun 05 09:41:15 sdr-aptv kernel:  do_init_module+0x4a/0x240
Jun 05 09:41:15 sdr-aptv kernel:  __do_sys_init_module+0x138/0x1b0
Jun 05 09:41:15 sdr-aptv kernel:  do_syscall_64+0x5c/0x90
Jun 05 09:41:15 sdr-aptv kernel:  ? syscall_exit_to_user_mode+0x26/0x50
Jun 05 09:41:15 sdr-aptv kernel:  ? do_syscall_64+0x6b/0x90
Jun 05 09:41:15 sdr-aptv kernel:  ? syscall_exit_to_user_mode+0x26/0x50
Jun 05 09:41:15 sdr-aptv kernel:  ? do_syscall_64+0x6b/0x90
Jun 05 09:41:15 sdr-aptv kernel:  ? syscall_exit_to_user_mode+0x26/0x50
Jun 05 09:41:15 sdr-aptv kernel:  ? do_syscall_64+0x6b/0x90
Jun 05 09:41:15 sdr-aptv kernel:  entry_SYSCALL_64_after_hwframe+0x44/0xae
Jun 05 09:41:15 sdr-aptv kernel: RIP: 0033:0x7f862b312c3e
Jun 05 09:41:15 sdr-aptv kernel: Code: 48 8b 0d 5d b1 0e 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 49 89 ca b8 af 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 2a b1 0e 00 f7 d8 64 89 01 48
Jun 05 09:41:15 sdr-aptv kernel: RSP: 002b:00007ffce1ba3df8 EFLAGS: 00000246 ORIG_RAX: 00000000000000af
Jun 05 09:41:15 sdr-aptv kernel: RAX: ffffffffffffffda RBX: 00005570e42d6e30 RCX: 00007f862b312c3e
Jun 05 09:41:15 sdr-aptv kernel: RDX: 00005570e42d6d70 RSI: 0000000000028b40 RDI: 00007f862afb0010
Jun 05 09:41:15 sdr-aptv kernel: RBP: 00007f862afb0010 R08: 0000000000049000 R09: 0000000000000000
Jun 05 09:41:15 sdr-aptv kernel: R10: 0000000000004211 R11: 0000000000000246 R12: 00005570e42d6d70
Jun 05 09:41:15 sdr-aptv kernel: R13: 00005570e42d6f40 R14: 00005570e42d6e30 R15: 00005570e42d7540
Jun 05 09:41:15 sdr-aptv kernel:  </TASK>
Jun 05 09:41:15 sdr-aptv kernel: Modules linked in: v4l2loopback(OE+) xt_conntrack xt_MASQUERADE nf_conntrack_netlink nfnetlink xt_addrtype iptable_filter iptable_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 libcrc32c br_netfilter bridge stp llc overlay rfcomm ccm cmac algif_hash algif_skcipher af_alg bnep bbswitch(OE) joydev snd_hda_codec_hdmi snd_sof_pci_intel_tgl dell_rbtn snd_sof_intel_hda_common hid_sensor_custom soundwire_intel soundwire_generic_allocation soundwire_cadence snd_sof_intel_hda hid_sensor_hub snd_ctl_led snd_sof_pci snd_sof_xtensa_dsp snd_sof intel_ishtp_hid snd_sof_utils snd_soc_hdac_hda dell_laptop snd_hda_ext_core hid_multitouch spi_nor uvcvideo iTCO_wdt snd_soc_acpi_intel_match dell_wmi intel_pmc_bxt mei_hdcp mei_pxp mei_wdt mtd ee1004 iTCO_vendor_support videobuf2_vmalloc snd_soc_acpi snd_hda_codec_realtek dell_smbios btusb pmt_telemetry videobuf2_memops pmt_class intel_rapl_msr soundwire_bus videobuf2_v4l2 dell_wmi_sysman intel_tcc_cooling btrtl dcdbas
Jun 05 09:41:15 sdr-aptv kernel:  snd_hda_codec_generic firmware_attributes_class dell_wmi_descriptor ledtrig_audio x86_pkg_temp_thermal wmi_bmof iwlmvm btbcm videobuf2_common intel_powerclamp snd_soc_core btintel videodev btmtk mousedev mac80211 coretemp libarc4 mc snd_compress bluetooth ac97_bus snd_pcm_dmaengine kvm_intel snd_hda_intel ecdh_generic iwlwifi i915 kvm snd_intel_dspcfg snd_intel_sdw_acpi irqbypass snd_hda_codec crct10dif_pclmul crc32_pclmul ghash_clmulni_intel snd_hda_core iwlmei aesni_intel snd_hwdep processor_thermal_device_pci_legacy crypto_simd cryptd intel_cstate snd_pcm drm_buddy processor_thermal_device intel_uncore cfg80211 snd_timer psmouse i2c_i801 processor_thermal_rfim pcspkr e1000e ttm mei_me intel_ish_ipc snd intel_lpss_pci rfkill processor_thermal_mbox intel_lpss spi_intel_pci soundcore spi_intel i2c_smbus iosm mei idma64 thunderbolt intel_ishtp intel_vsec drm_dp_helper tpm_crb processor_thermal_rapl intel_rapl_common intel_gtt intel_soc_dts_iosf tpm_tis ucsi_acpi typec_ucsi
Jun 05 09:41:15 sdr-aptv kernel:  tpm_tis_core typec tpm roles rng_core i2c_hid_acpi mac_hid wmi i2c_hid int3403_thermal int340x_thermal_zone intel_hid video int3400_thermal acpi_pad acpi_tad sparse_keymap acpi_thermal_rel sg crypto_user acpi_call(OE) fuse bpf_preload ip_tables x_tables ext4 crc32c_generic crc16 mbcache jbd2 usbhid rtsx_pci_sdmmc serio_raw mmc_core atkbd libps2 vivaldi_fmap nvme xhci_pci crc32c_intel rtsx_pci nvme_core xhci_pci_renesas i8042 serio
Jun 05 09:41:15 sdr-aptv kernel: ---[ end trace 0000000000000000 ]---
Jun 05 09:41:15 sdr-aptv kernel: RIP: 0010:exc_control_protection+0xc2/0xd0
Jun 05 09:41:15 sdr-aptv kernel: Code: 8b 93 80 00 00 00 be f9 00 00 00 48 c7 c7 83 ab c6 8e e8 d1 f1 4f ff e9 72 ff ff ff 48 c7 c7 6a ab c6 8e e8 c7 21 fb ff 0f 0b <0f> 0b 66 66 2e 0f 1f 84 00 00 00 00 00 90 66 0f 1f 00 55 53 48 89
Jun 05 09:41:15 sdr-aptv kernel: RSP: 0018:ffffabf1c3b4fc58 EFLAGS: 00010002
Jun 05 09:41:15 sdr-aptv kernel: RAX: 000000000000003b RBX: ffffabf1c3b4fc78 RCX: 0000000000000000
Jun 05 09:41:15 sdr-aptv kernel: RDX: 0000000000000000 RSI: ffff91b54f4e16a0 RDI: ffff91b54f4e16a0
Jun 05 09:41:15 sdr-aptv kernel: RBP: 0000000000000003 R08: 0000000000000000 R09: ffffabf1c3b4fa78
Jun 05 09:41:15 sdr-aptv kernel: R10: 0000000000000003 R11: ffffffff8f4caa08 R12: 0000000000000000
Jun 05 09:41:15 sdr-aptv kernel: R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
Jun 05 09:41:15 sdr-aptv kernel: FS:  00007f862b8e4740(0000) GS:ffff91b54f4c0000(0000) knlGS:0000000000000000
Jun 05 09:41:15 sdr-aptv kernel: CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
Jun 05 09:41:15 sdr-aptv kernel: CR2: ffffffffc09d6fd6 CR3: 0000000116aae001 CR4: 0000000000f70ee0
Jun 05 09:41:15 sdr-aptv kernel: PKRU: 55555554

By the way: ibt-=off makes v4l2loopback work, but then my Chromium - Version 102.0.5005.61 (Official Build) Arch Linux (64-bit) - gets stuck on startup with the only trace in the journal:

Jun 04 21:47:20 sdr-aptv kernel: v4l2loopback driver version 0.12.5 loaded
Jun 04 21:49:31 sdr-aptv kernel: INFO: task kworker/u32:0:8 blocked for more than 122 seconds.
Jun 04 21:49:31 sdr-aptv kernel:       Tainted: G           OE     5.18.1-arch1-1 #1
Jun 04 21:49:31 sdr-aptv kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
Jun 04 21:49:31 sdr-aptv kernel: task:kworker/u32:0   state:D stack:    0 pid:    8 ppid:     2 flags:0x00004000
Jun 04 21:49:31 sdr-aptv kernel: Workqueue: events_power_efficient reg_check_chans_work [cfg80211]
Jun 04 21:49:31 sdr-aptv kernel: Call Trace:
Jun 04 21:49:31 sdr-aptv kernel:  <TASK>
Jun 04 21:49:31 sdr-aptv kernel:  __schedule+0x37c/0x11f0
Jun 04 21:49:31 sdr-aptv kernel:  schedule+0x4f/0xb0
Jun 04 21:49:31 sdr-aptv kernel:  schedule_preempt_disabled+0x15/0x20
Jun 04 21:49:31 sdr-aptv kernel:  __mutex_lock.constprop.0+0x2d0/0x480
Jun 04 21:49:31 sdr-aptv kernel:  ? __update_idle_core+0x1f/0xb0
Jun 04 21:49:31 sdr-aptv kernel:  ? __switch_to_asm+0x46/0x70
Jun 04 21:49:31 sdr-aptv kernel:  reg_check_chans_work+0x31/0x400 [cfg80211 6c8a3866f60be53418f2b19fc604cae5d6ef316a]
Jun 04 21:49:31 sdr-aptv kernel:  ? __schedule+0x384/0x11f0
Jun 04 21:49:31 sdr-aptv kernel:  ? frontbuffer_retire+0x42/0xb0 [i915 b05e33731b416f41f19b20a59439652d0c528789]
Jun 04 21:49:31 sdr-aptv kernel:  process_one_work+0x1c4/0x380
Jun 04 21:49:31 sdr-aptv kernel:  worker_thread+0x51/0x380
Jun 04 21:49:31 sdr-aptv kernel:  ? rescuer_thread+0x3a0/0x3a0
Jun 04 21:49:31 sdr-aptv kernel:  kthread+0xdb/0x110
Jun 04 21:49:31 sdr-aptv kernel:  ? kthread_complete_and_exit+0x20/0x20
Jun 04 21:49:31 sdr-aptv kernel:  ret_from_fork+0x1f/0x30
Jun 04 21:49:31 sdr-aptv kernel:  </TASK>
Jun 04 21:49:31 sdr-aptv kernel: INFO: task kworker/u32:2:134 blocked for more than 122 seconds.
Jun 04 21:49:31 sdr-aptv kernel:       Tainted: G           OE     5.18.1-arch1-1 #1
Jun 04 21:49:31 sdr-aptv kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
Jun 04 21:49:31 sdr-aptv kernel: task:kworker/u32:2   state:D stack:    0 pid:  134 ppid:     2 flags:0x00004000
Jun 04 21:49:31 sdr-aptv kernel: Workqueue: events_power_efficient crda_timeout_work [cfg80211]
Jun 04 21:49:31 sdr-aptv kernel: Call Trace:
Jun 04 21:49:31 sdr-aptv kernel:  <TASK>
Jun 04 21:49:31 sdr-aptv kernel:  __schedule+0x37c/0x11f0
Jun 04 21:49:31 sdr-aptv kernel:  schedule+0x4f/0xb0
Jun 04 21:49:31 sdr-aptv kernel:  schedule_preempt_disabled+0x15/0x20
Jun 04 21:49:31 sdr-aptv kernel:  __mutex_lock.constprop.0+0x2d0/0x480
Jun 04 21:49:31 sdr-aptv kernel:  crda_timeout_work+0x10/0x40 [cfg80211 6c8a3866f60be53418f2b19fc604cae5d6ef316a]
Jun 04 21:49:31 sdr-aptv kernel:  process_one_work+0x1c4/0x380
Jun 04 21:49:31 sdr-aptv kernel:  worker_thread+0x51/0x380
Jun 04 21:49:31 sdr-aptv kernel:  ? rescuer_thread+0x3a0/0x3a0
Jun 04 21:49:31 sdr-aptv kernel:  kthread+0xdb/0x110
Jun 04 21:49:31 sdr-aptv kernel:  ? kthread_complete_and_exit+0x20/0x20
Jun 04 21:49:31 sdr-aptv kernel:  ret_from_fork+0x1f/0x30
Jun 04 21:49:31 sdr-aptv kernel:  </TASK>
Jun 04 21:49:31 sdr-aptv kernel: INFO: task kworker/13:1:156 blocked for more than 122 seconds.
Jun 04 21:49:31 sdr-aptv kernel:       Tainted: G           OE     5.18.1-arch1-1 #1
Jun 04 21:49:31 sdr-aptv kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
Jun 04 21:49:31 sdr-aptv kernel: task:kworker/13:1    state:D stack:    0 pid:  156 ppid:     2 flags:0x00004000
Jun 04 21:49:31 sdr-aptv kernel: Workqueue: events reg_todo [cfg80211]
Jun 04 21:49:31 sdr-aptv kernel: Call Trace:
Jun 04 21:49:31 sdr-aptv kernel:  <TASK>
Jun 04 21:49:31 sdr-aptv kernel:  __schedule+0x37c/0x11f0
Jun 04 21:49:31 sdr-aptv kernel:  ? lock_timer_base+0x61/0x80
Jun 04 21:49:31 sdr-aptv kernel:  schedule+0x4f/0xb0
Jun 04 21:49:31 sdr-aptv kernel:  schedule_preempt_disabled+0x15/0x20
Jun 04 21:49:31 sdr-aptv kernel:  __mutex_lock.constprop.0+0x2d0/0x480
Jun 04 21:49:31 sdr-aptv kernel:  reg_process_self_managed_hints+0x32/0xa0 [cfg80211 6c8a3866f60be53418f2b19fc604cae5d6ef316a]
Jun 04 21:49:31 sdr-aptv kernel:  reg_todo+0x1da/0x230 [cfg80211 6c8a3866f60be53418f2b19fc604cae5d6ef316a]
Jun 04 21:49:31 sdr-aptv kernel:  process_one_work+0x1c4/0x380
Jun 04 21:49:31 sdr-aptv kernel:  worker_thread+0x51/0x380
Jun 04 21:49:31 sdr-aptv kernel:  ? rescuer_thread+0x3a0/0x3a0
Jun 04 21:49:31 sdr-aptv kernel:  kthread+0xdb/0x110
Jun 04 21:49:31 sdr-aptv kernel:  ? kthread_complete_and_exit+0x20/0x20
Jun 04 21:49:31 sdr-aptv kernel:  ret_from_fork+0x1f/0x30
Jun 04 21:49:31 sdr-aptv kernel:  </TASK>

OS / HW config is:

neofetch

                   -`                    pswiatki@sdr-aptv 
                  .o+`                   ----------------- 
                 `ooo/                   OS: Arch Linux x86_64 
                `+oooo:                  Host: Precision 3561 
               `+oooooo:                 Kernel: 5.18.1-arch1-1 
               -+oooooo+:                Uptime: 19 mins 
             `/:-:++oooo+:               Packages: 1472 (pacman) 
            `/++++/+++++++:              Shell: bash 5.1.16 
           `/++++++++++++++:             Resolution: 1920x1080, 2560x1440 
          `/+++ooooooooooooo/`           DE: LXDE 
         ./ooosssso++osssssso+`          WM: Openbox 
        .oossssso-````/ossssss+`         WM Theme: Artwiz-boxed 
       -osssssso.      :ssssssso.        Theme: Clearlooks [GTK2/3] 
      :osssssss/        osssso+++.       Icons: nuoveXT2 [GTK2/3] 
     /ossssssss/        +ssssooo/-       Terminal: lxterminal 
   `/ossssso+/:-        -:/+osssso+-     Terminal Font: DejaVu Sans Mono 11 
  `+sso+:-`                 `.-/+oso:    CPU: 11th Gen Intel i7-11850H (16) @ 4.800GHz 
 `++:.                           `-/+/   GPU: NVIDIA T600 Mobile 
 .`                                 `/   GPU: Intel TigerLake-H GT1 [UHD Graphics] 
                                         Memory: 3101MiB / 64035MiB

lshw -class cpu

  *-cpu                     
       description: CPU
       product: 11th Gen Intel(R) Core(TM) i7-11850H @ 2.50GHz
       vendor: Intel Corp.
       physical id: 400
       bus info: cpu@0
       version: 11th Gen Intel(R) Core(TM) i7-11850H @ 2.50GHz
       slot: U3E1
       size: 800MHz
       capacity: 4800MHz
       width: 64 bits
       clock: 100MHz
       capabilities: lm fpu fpu_exception wp vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp x86-64 constant_tsc art arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc cpuid aperfmperf tsc_known_freq pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 sdbg fma cx16 xtpr pdcm pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm abm 3dnowprefetch cpuid_fault epb cat_l2 invpcid_single cdp_l2 ssbd ibrs ibpb stibp ibrs_enhanced tpr_shadow vnmi flexpriority ept vpid ept_ad fsgsbase tsc_adjust bmi1 avx2 smep bmi2 erms invpcid rdt_a avx512f avx512dq rdseed adx smap avx512ifma clflushopt clwb intel_pt avx512cd sha_ni avx512bw avx512vl xsaveopt xsavec xgetbv1 xsaves split_lock_detect dtherm ida arat pln pts hwp hwp_notify hwp_act_window hwp_epp hwp_pkg_req avx512vbmi umip pku ospke avx512_vbmi2 gfni vaes vpclmulqdq avx512_vnni avx512_bitalg tme avx512_vpopcntdq rdpid movdiri movdir64b fsrm avx512_vp2intersect md_clear ibt flush_l1d arch_capabilities cpufreq
       configuration: cores=8 enabledcores=8 threads=16

ProfeJulianLasso commented 2 years ago

i have the same problem :(

MauroSoli commented 2 years ago

Same for me.

GeorgFoc commented 2 years ago

And I am also affected.

umlaeute commented 2 years ago

i'm sure it is unrelated to "11th+ gen Intel processors since kernel 5.18".

$ lscpu 
Architecture:            x86_64
  CPU op-mode(s):        32-bit, 64-bit
  Address sizes:         39 bits physical, 48 bits virtual
  Byte Order:            Little Endian
CPU(s):                  8
  On-line CPU(s) list:   0-7
Vendor ID:               GenuineIntel
  Model name:            11th Gen Intel(R) Core(TM) i5-1145G7 @ 2.60GHz
$ uname -a
Linux umlautT 5.18.0-3-amd64 #1 SMP PREEMPT_DYNAMIC Debian 5.18.14-1 (2022-07-23) x86_64 GNU/Linux
$ sudo modprobe v4l2loopback
$ sudo dmesg | tail -1
[430342.292879] v4l2loopback driver version 0.12.7 loaded

umlaeute commented 2 years ago

the problem seems to be the enabling of IBT on Arch-kernels.

As a temporary workaround, you can disable it by adding ibt=off to your kernel params. see https://github.com/NVIDIA/open-gpu-kernel-modules/issues/256#issuecomment-1138851460

(and i just noticed that this workaround is already mentioned by the OP)

xnox commented 2 years ago

main branch & v0.12.7 contain https://github.com/umlaeute/v4l2loopback/commit/ddce39b5eb667d3a5db0009f96f6050496bd58ad which should resolve this. For me I am able to build this module on IBT-enabled kernel and load it.

umlaeute / v4l2loopback