Kernel scheduler warning when running 5.13.0-22-generic

[Yensong Ted Li]

Unexpected kernel warning is the issue.

Copied from dmesg output:
[ 169.603326] ------------[ cut here ]------------
[ 169.603329] rq->tmp_alone_branch != &rq->leaf_cfs_rq_list
[ 169.603332] WARNING: CPU: 9 PID: 2086 at kernel/sched/fair.c:401 enqueue_task_fair+0x25c/0x5c0
[ 169.603340] Modules linked in: udp_diag tcp_diag inet_diag rfcomm xt_MASQUERADE nf_conntrack_netlink nfnetlink xfrm_user xfrm_algo iptable_nat nf_nat br_netfilter bridge stp llc snd_seq_dummy snd_hrtimer cmac algif_hash algif_skcipher af_alg aufs bnep overlay btusb btrtl btbcm btintel sch_fq_codel bluetooth intel_rapl_msr i2c_amd_mp2_pci intel_rapl_common ecdh_generic ee1004 ecc edac_mce_amd amdgpu uvcvideo videobuf2_vmalloc videobuf2_memops snd_hda_codec_realtek videobuf2_v4l2 snd_hda_codec_generic videobuf2_common ledtrig_audio snd_hda_codec_hdmi kvm_amd snd_hda_intel snd_intel_dspcfg kvm snd_intel_sdw_acpi snd_usb_audio snd_hda_codec snd_usbmidi_lib snd_hda_core iommu_v2 gpu_sched crct10dif_pclmul snd_hwdep drm_ttm_helper snd_seq_midi ghash_clmulni_intel snd_seq_midi_event ttm aesni_intel snd_rawmidi drm_kms_helper crypto_simd snd_seq snd_pcm videodev cryptd cec snd_seq_device nls_iso8859_1 rapl wmi_bmof mc efi_pstore k10temp rc_core snd_timer ucsi_ccg i2c_algo_bit typec_ucsi
[ 169.603389] fb_sys_fops ccp syscopyarea snd sysfillrect typec joydev input_leds sysimgblt soundcore ryzen_smu(OE) mac_hid ip6t_REJECT nf_reject_ipv6 88x2bu(OE) xt_hl ip6t_rt ipt_REJECT nf_reject_ipv4 xt_LOG nf_log_syslog xt_limit xt_addrtype xt_tcpudp xt_conntrack nf_conntrack cfg80211 nf_defrag_ipv6 nf_defrag_ipv4 libcrc32c nct6775 hwmon_vid ip6table_filter ip6_tables msr parport_pc iptable_filter ppdev bpfilter lp drm parport ip_tables x_tables autofs4 hid_generic usbhid hid uas usb_storage crc32_pclmul r8169 ahci nvme gpio_amdpt xhci_pci i2c_piix4 i2c_designware_pci realtek nvme_core libahci xhci_pci_renesas wmi gpio_generic
[ 169.603425] CPU: 9 PID: 2086 Comm: panel-15-cpugra Tainted: G OE 5.13.0-22-generic #22~20.04.1-Ubuntu
[ 169.603428] Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./B450M Pro4, BIOS P5.20 06/28/2021
[ 169.603430] RIP: 0010:enqueue_task_fair+0x25c/0x5c0
[ 169.603434] Code: e0 09 00 00 0f 84 b7 fe ff ff 80 3d 53 4b 02 02 00 0f 85 aa fe ff ff 48 c7 c7 70 1a 1c b5 c6 05 3f 4b 02 02 01 e8 ab 72 aa 00 <0f> 0b e9 90 fe ff ff 48 8b be 48 01 00 00 4c 8d 86 40 01 00 00 4c
[ 169.603435] RSP: 0000:ffffb3ac037b7d00 EFLAGS: 00010086
[ 169.603438] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000027
[ 169.603439] RDX: 0000000000000027 RSI: 00000000ffffdfff RDI: ffff8c6a6ea589c8
[ 169.603440] RBP: ffffb3ac037b7d38 R08: ffff8c6a6ea589c0 R09: ffffb3ac037b7ad8
[ 169.603441] R10: 0000000000000001 R11: 0000000000000001 R12: ffff8c6a6e82cf80
[ 169.603442] R13: ffff8c6a6e82ce80 R14: 0000000000000000 R15: 0000000000000001
[ 169.603444] FS: 00007fe790f2fa80(0000) GS:ffff8c6a6ea40000(0000) knlGS:0000000000000000
[ 169.603445] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 169.603446] CR2: 00007f982f4e94c0 CR3: 000000015c4a2000 CR4: 0000000000750ee0
[ 169.603448] PKRU: 55555554
[ 169.603449] Call Trace:
[ 169.603452] ttwu_do_activate+0x9d/0x490
[ 169.603455] ? sched_clock_cpu+0x11/0xb0
[ 169.603457] try_to_wake_up+0x1fc/0x570
[ 169.603459] wake_up_process+0x15/0x20
[ 169.603461] swake_up_locked.part.0+0x17/0x30
[ 169.603464] swake_up_one+0x2f/0x40
[ 169.603466] rcu_gp_kthread_wake+0x57/0x70
[ 169.603469] rcu_accelerate_cbs_unlocked+0x65/0x80
[ 169.603472] rcu_core+0x244/0x280
[ 169.603475] rcu_core_si+0xe/0x10
[ 169.603477] __do_softirq+0xe0/0x29b
[ 169.603481] irq_exit_rcu+0xa4/0xb0
[ 169.603484] sysvec_apic_timer_interrupt+0x43/0x90
[ 169.603486] ? asm_sysvec_apic_timer_interrupt+0xa/0x20
[ 169.603489] asm_sysvec_apic_timer_interrupt+0x12/0x20
[ 169.603491] RIP: 0033:0x7fe79291c36e
[ 169.603493] Code: 28 00 00 00 75 2a 48 83 c4 20 5b 5d 41 5c c3 0f 1f 44 00 00 48 8b 7b 08 48 89 e6 e8 fc 65 21 00 8b 04 24 29 45 00 8b 44 24 04 <41> 29 04 24 eb c6 e8 d7 c8 f0 ff 0f 1f 80 00 00 00 00 f3 0f 1e fa
[ 169.603495] RSP: 002b:00007ffd55c92610 EFLAGS: 00000202
[ 169.603496] RAX: 0000000000000002 RBX: 00005620fc8881b0 RCX: 0000000000000000
[ 169.603497] RDX: 0000000000000001 RSI: 00005620fc6302d0 RDI: 0000000000000002
[ 169.603498] RBP: 00007ffd55c92690 R08: 0000000000000001 R09: 0000000000000022
[ 169.603499] R10: 00007fe792a36220 R11: 0000000000000001 R12: 00007ffd55c92694
[ 169.603500] R13: 00005620fc8881b0 R14: 00005620fc9268d0 R15: 0000000000000008
[ 169.603502] ---[ end trace 788552cc565f5a16 ]---

uname -a output:
Linux tedlibuilt-desktop 5.13.0-22-generic #22~20.04.1-Ubuntu SMP Tue Nov 9 15:07:24 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux

lsb_release -a:
Distributor ID: Ubuntu
Description: Ubuntu 20.04.3 LTS
Release: 20.04
Codename: focal

linux-generic-hwe-20.04-edge version: 5.13.0.22.22~20.04.9
linux-image-5.13.0-22-generic version: 5.13.0-22.22~20.04.1

Will be more than happy to provide any extra relevant information/program outputs/logs if requested.

[Yensong Ted Li (yslited-linux)]

I'm not sure but could this bug be related to the following two other kernel bugs?

1. https://bugzilla.redhat.com/show_bug.cgi?id=1986350

2. https://lists.archive.carbon60.com/linux/kernel/3616984