BUG: workqueue lockup - pool cpus=1 node=0 flags=0x0 nice=0 stuck for 141s! BUG: workqueue lockup - pool cpus=1 node=0 flags=0x0 nice=-20 stuck for 140s! Showing busy workqueues and worker pools: workqueue events: flags=0x0 pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=6/256 refcnt=7 pending: 3*nsim_dev_hwstats_traffic_work, 2*ovs_dp_masks_rebalance, kfree_rcu_monitor pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=12/256 refcnt=13 in-flight: 5872:switchdev_deferred_process_work switchdev_deferred_process_work pending: vmstat_shepherd, nsim_dev_hwstats_traffic_work, ovs_dp_masks_rebalance, 4*psi_avgs_work, 2*ovs_dp_masks_rebalance, kfree_rcu_monitor workqueue events_long: flags=0x0 pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=3/256 refcnt=4 pending: 3*defense_work_handler pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=3/256 refcnt=4 pending: 3*defense_work_handler workqueue events_unbound: flags=0x2 pwq 4: cpus=0-1 flags=0x4 nice=0 active=12/512 refcnt=13 in-flight: 59:linkwatch_event linkwatch_event pending: 3*cfg80211_wiphy_work, flush_memcg_stats_dwork, macvlan_process_broadcast, crng_reseed, 4*macvlan_process_broadcast pwq 4: cpus=0-1 flags=0x4 nice=0 active=9/512 refcnt=10 in-flight: 42:toggle_allocation_gate pending: 3*cfg80211_wiphy_work, 4*nsim_dev_trap_report_work, macvlan_process_broadcast workqueue events_freezable: flags=0x4 pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2 pending: update_balloon_stats_func workqueue events_power_efficient: flags=0x80 pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=6/256 refcnt=7 pending: neigh_managed_work, gc_worker, neigh_managed_work, 2*neigh_periodic_work, reg_check_chans_work pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=3/256 refcnt=4 pending: wg_ratelimiter_gc_entries, do_cache_clean, check_lifetime workqueue netns: flags=0xe000a pwq 4: cpus=0-1 flags=0x4 nice=0 active=1/1 refcnt=4 in-flight: 11:cleanup_net workqueue mm_percpu_wq: flags=0x8 pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=1/256 refcnt=2 pending: vmstat_update pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2 pending: vmstat_update workqueue writeback: flags=0x4a pwq 4: cpus=0-1 flags=0x4 nice=0 active=3/256 refcnt=4 pending: wb_update_bandwidth_workfn, 2*wb_workfn workqueue kblockd: flags=0x18 pwq 3: cpus=1 node=0 flags=0x0 nice=-20 active=2/256 refcnt=3 pending: 2*blk_mq_timeout_work pwq 1: cpus=0 node=0 flags=0x0 nice=-20 active=2/256 refcnt=3 pending: blk_mq_requeue_work, blk_mq_timeout_work workqueue dm_bufio_cache: flags=0x8 pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=1/256 refcnt=2 pending: work_fn workqueue ipv6_addrconf: flags=0xe000a pwq 4: cpus=0-1 flags=0x4 nice=0 active=1/1 refcnt=9 pending: addrconf_verify_work inactive: 5*addrconf_verify_work workqueue krxrpcd: flags=0xa001a pwq 5: cpus=0-1 node=0 flags=0x4 nice=-20 active=1/1 refcnt=8 pending: rxrpc_peer_keepalive_worker inactive: 4*rxrpc_peer_keepalive_worker workqueue bat_events: flags=0xe000a pwq 4: cpus=0-1 flags=0x4 nice=0 active=1/1 refcnt=42 in-flight: 2891:batadv_nc_worker inactive: 4*batadv_nc_worker, batadv_purge_orig, 5*batadv_mcast_mla_update, batadv_purge_orig, 2*batadv_iv_send_outstanding_bat_ogm_packet, 3*batadv_purge_orig, 7*batadv_iv_send_outstanding_bat_ogm_packet, 5*batadv_tt_purge, batadv_bla_periodic_work, batadv_dat_purge, batadv_bla_periodic_work, batadv_dat_purge, 2*batadv_bla_periodic_work, 3*batadv_dat_purge, batadv_bla_periodic_work workqueue hci0: flags=0xa0012 pwq 5: cpus=0-1 node=0 flags=0x4 nice=-20 active=1/1 refcnt=4 pending: hci_conn_timeout workqueue hci1: flags=0xa0012 pwq 5: cpus=0-1 node=0 flags=0x4 nice=-20 active=1/1 refcnt=4 pending: hci_conn_timeout workqueue hci3: flags=0xa0012 pwq 5: cpus=0-1 node=0 flags=0x4 nice=-20 active=1/1 refcnt=4 pending: hci_conn_timeout workqueue wg-crypt-wg0: flags=0x28 pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=1/256 refcnt=2 pending: wg_packet_encrypt_worker pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2 pending: wg_packet_encrypt_worker workqueue wg-crypt-wg1: flags=0x28 pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=1/256 refcnt=2 pending: wg_packet_encrypt_worker pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2 pending: wg_packet_encrypt_worker workqueue wg-crypt-wg2: flags=0x28 pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=1/256 refcnt=2 pending: wg_packet_encrypt_worker pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2 pending: wg_packet_encrypt_worker workqueue wg-crypt-wg0: flags=0x28 pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=1/256 refcnt=2 pending: wg_packet_encrypt_worker pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2 pending: wg_packet_encrypt_worker workqueue wg-crypt-wg1: flags=0x28 pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=1/256 refcnt=2 pending: wg_packet_encrypt_worker pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2 pending: wg_packet_encrypt_worker workqueue wg-crypt-wg2: flags=0x28 pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=1/256 refcnt=2 pending: wg_packet_encrypt_worker pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2 pending: wg_packet_encrypt_worker workqueue wg-crypt-wg0: flags=0x28 pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=1/256 refcnt=2 pending: wg_packet_encrypt_worker pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2 pending: wg_packet_encrypt_worker workqueue wg-crypt-wg1: flags=0x28 pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=1/256 refcnt=2 pending: wg_packet_encrypt_worker pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2 pending: wg_packet_encrypt_worker workqueue wg-crypt-wg2: flags=0x28 pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=1/256 refcnt=2 pending: wg_packet_encrypt_worker pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2 pending: wg_packet_encrypt_worker workqueue hci2: flags=0xa0012 pwq 5: cpus=0-1 node=0 flags=0x4 nice=-20 active=1/1 refcnt=5 pending: hci_cmd_timeout inactive: hci_conn_timeout pool 0: cpus=0 node=0 flags=0x0 nice=0 hung=142s workers=6 idle: 8 788 9 969 5854 pool 4: cpus=0-1 flags=0x4 nice=0 hung=142s workers=10 idle: 48 6409 12 62 2897 3471 Showing backtraces of running workers in stalled CPU-bound worker pools: ------------[ cut here ]------------ WARNING: CPU: 0 PID: 29 at kernel/rcu/tree_stall.h:1001 rcu_check_gp_start_stall+0x2dc/0x460 kernel/rcu/tree_stall.h:993 Modules linked in: CPU: 0 PID: 29 Comm: khungtaskd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:rcu_check_gp_start_stall+0x2dc/0x460 kernel/rcu/tree_stall.h:1001 Code: ff ff ff 48 c7 c7 a0 04 ef 96 be 04 00 00 00 e8 5a ae 6c 00 48 89 df b8 01 00 00 00 87 05 ac d5 7e 15 85 c0 0f 85 19 ff ff ff <0f> 0b 48 81 ff 80 56 d3 8c 74 47 48 c7 c0 9c c9 4a 8e 48 c1 e8 03 RSP: 0018:ffffc90000007bb8 EFLAGS: 00010046 RAX: 0000000000000000 RBX: ffffffff8cd35680 RCX: ffffffff81702ee6 RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffffff8cd35680 RBP: ffffc90000007e30 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffffbfff2dde094 R12: 0000000000002904 R13: 1ffff110171c7a6a R14: 0000000000000a02 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f8d124d8623 CR3: 0000000031324000 CR4: 00000000003506f0 Call Trace: rcu_core+0x612/0x1720 kernel/rcu/tree.c:2462 handle_softirqs+0x280/0x820 kernel/softirq.c:578 __do_softirq kernel/softirq.c:612 [inline] invoke_softirq kernel/softirq.c:452 [inline] __irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline] sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:console_flush_all+0x889/0xd00 arch/x86/include/asm/irqflags.h:-1 Code: ed 01 00 00 e8 88 2a 1b 00 4d 85 ff 48 8b 5c 24 38 75 07 e8 79 2a 1b 00 eb 06 e8 72 2a 1b 00 fb 49 bf 00 00 00 00 00 fc ff df <48> 8b 44 24 50 42 0f b6 04 38 84 c0 0f 85 2f 02 00 00 80 3b 01 0f RSP: 0018:ffffc90000a5f780 EFLAGS: 00000293 RAX: ffffffff816a65ce RBX: ffffc90000a5f91f RCX: ffff8880186c0000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc90000a5f8f0 R08: ffffffff90da7507 R09: 1ffffffff21b4ea0 R10: dffffc0000000000 R11: fffffbfff21b4ea1 R12: ffffffff8d4b5d40 R13: 1ffffffff19792f8 R14: ffffffff8d4b5d98 R15: dffffc0000000000 console_unlock+0xae/0x340 kernel/printk/printk.c:3069 vprintk_emit+0x477/0x600 kernel/printk/printk.c:2341 _printk+0xd0/0x110 kernel/printk/printk.c:2366 print_worker_info+0x2bb/0x2f0 kernel/workqueue.c:5096 sched_show_task+0x461/0x5a0 kernel/sched/core.c:9176 check_hung_task kernel/hung_task.c:140 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:213 [inline] watchdog+0xb70/0xf80 kernel/hung_task.c:379 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 ---------------- Code disassembly (best guess): 0: ed in (%dx),%eax 1: 01 00 add %eax,(%rax) 3: 00 e8 add %ch,%al 5: 88 2a mov %ch,(%rdx) 7: 1b 00 sbb (%rax),%eax 9: 4d 85 ff test %r15,%r15 c: 48 8b 5c 24 38 mov 0x38(%rsp),%rbx 11: 75 07 jne 0x1a 13: e8 79 2a 1b 00 call 0x1b2a91 18: eb 06 jmp 0x20 1a: e8 72 2a 1b 00 call 0x1b2a91 1f: fb sti 20: 49 bf 00 00 00 00 00 movabs $0xdffffc0000000000,%r15 27: fc ff df * 2a: 48 8b 44 24 50 mov 0x50(%rsp),%rax <-- trapping instruction 2f: 42 0f b6 04 38 movzbl (%rax,%r15,1),%eax 34: 84 c0 test %al,%al 36: 0f 85 2f 02 00 00 jne 0x26b 3c: 80 3b 01 cmpb $0x1,(%rbx) 3f: 0f .byte 0xf