rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P3577/1:b..l rcu: (detected by 1, t=10502 jiffies, g=111253, q=350 ncpus=2) task:kworker/u8:16 state:R running task stack:18424 pid:3577 tgid:3577 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: events_unbound nsim_dev_trap_report_work Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x1480/0x50a0 kernel/sched/core.c:6863 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7190 irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:__sanitizer_cov_trace_pc+0x6c/0x80 kernel/kcov.c:235 Code: 18 16 00 00 83 fa 02 75 21 48 8b 91 20 16 00 00 48 8b 32 48 8d 7e 01 8b 89 1c 16 00 00 48 39 cf 73 08 48 89 3a 48 89 44 f2 08 8f 03 17 09 cc 66 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 RSP: 0018:ffffc9000ccf7798 EFLAGS: 00000293 RAX: ffffffff850e7c83 RBX: dffffc0000000000 RCX: ffff888030dd8000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000 R10: ffffc9000ccf7880 R11: fffff5200199ef18 R12: 1ffff9200199ef00 R13: 0000000000000001 R14: ffff888030dd8480 R15: 1ffff110061bb090 crng_make_state+0x133/0x5e0 drivers/char/random.c:368 _get_random_bytes+0xd5/0x210 drivers/char/random.c:406 nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:846 [inline] nsim_dev_trap_report drivers/net/netdevsim/dev.c:875 [inline] nsim_dev_trap_report_work+0x6b1/0xbc0 drivers/net/netdevsim/dev.c:921 process_one_work kernel/workqueue.c:3257 [inline] process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 rcu: rcu_preempt kthread timer wakeup didn't happen for 10471 jiffies! g111253 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=94823 rcu: rcu_preempt kthread starved for 10472 jiffies! g111253 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=0 rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior. rcu: RCU grace-period kthread stack dump: task:rcu_preempt state:I stack:23320 pid:18 tgid:18 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x1480/0x50a0 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] schedule+0x165/0x360 kernel/sched/core.c:6960 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Tainted: G L syzkaller #0 PREEMPT_{RT,(full)} Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82 Code: cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 63 b6 14 00 f3 0f 1e fa fb f4 cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffffff8d207d80 EFLAGS: 000002c2 RAX: de0d7f693af54600 RBX: ffffffff819654fa RCX: de0d7f693af54600 RDX: 0000000000000001 RSI: ffffffff8ce0c048 RDI: ffffffff8b3f5760 RBP: ffffffff8d207ea8 R08: ffff8880b8833c5b R09: 1ffff1101710678b R10: dffffc0000000000 R11: ffffed101710678c R12: ffffffff8edb3370 R13: 1ffffffff1a60668 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888126d01000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055556b2d25c8 CR3: 0000000023a30000 CR4: 00000000003526f0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x73/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:191 [inline] do_idle+0x1ea/0x520 kernel/sched/idle.c:332 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:430 rest_init+0x2de/0x300 init/main.c:757 start_kernel+0x3a7/0x400 init/main.c:1206 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310 x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291 common_startup_64+0x13e/0x147 BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 258s! BUG: workqueue lockup - pool cpus=0-1 flags=0x4 nice=0 stuck for 259s! Showing busy workqueues and worker pools: workqueue events: flags=0x100 pwq 2: cpus=0 node=0 flags=0x0 nice=0 active=14 refcnt=15 pending: 8*nsim_dev_hwstats_traffic_work, psi_avgs_work, fqdir_free_fn, psi_avgs_work, 2*ovs_dp_masks_rebalance, vmstat_shepherd pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=1 refcnt=2 pending: l2cap_chan_timeout workqueue events_highpri: flags=0x110 pwq 7: cpus=1 node=0 flags=0x0 nice=-20 active=1 refcnt=3 in-flight: 14466:snd_vmidi_output_work BAR(16573) workqueue events_long: flags=0x100 pwq 2: cpus=0 node=0 flags=0x0 nice=0 active=6 refcnt=7 pending: 5*defense_work_handler, br_fdb_cleanup pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=1 refcnt=2 pending: br_fdb_cleanup workqueue events_unbound: flags=0x2 pwq 8: cpus=0-1 flags=0x4 nice=0 active=1 refcnt=2 pending: toggle_allocation_gate pwq 8: cpus=0-1 flags=0x4 nice=0 active=1 refcnt=2 pending: flush_memcg_stats_dwork workqueue events_unbound: flags=0x2 pwq 8: cpus=0-1 flags=0x4 nice=0 active=13 refcnt=14 pending: 3*cfg80211_wiphy_work, 9*nsim_dev_trap_report_work, crng_reseed pwq 8: cpus=0-1 flags=0x4 nice=0 active=6 refcnt=7 in-flight: 3577:nsim_dev_trap_report_work pending: cfg80211_wiphy_work, idle_cull_fn, 3*macvlan_process_broadcast workqueue events_freezable: flags=0x104 pwq 2: cpus=0 node=0 flags=0x0 nice=0 active=1 refcnt=2 pending: update_balloon_stats_func workqueue events_power_efficient: flags=0x180 pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=10 refcnt=11 in-flight: 16436:gc_worker pending: wg_ratelimiter_gc_entries, 2*neigh_managed_work, 2*neigh_periodic_work, do_cache_clean, 3*check_lifetime workqueue kvfree_rcu_reclaim: flags=0xa pwq 8: cpus=0-1 flags=0x4 nice=0 active=1 refcnt=2 pending: kfree_rcu_monitor pwq 8: cpus=0-1 flags=0x4 nice=0 active=1 refcnt=2 pending: kfree_rcu_monitor workqueue netns: flags=0x6000a pwq 8: cpus=0-1 flags=0x4 nice=0 active=1 refcnt=5 in-flight: 13143:cleanup_net inactive: cleanup_net workqueue mm_percpu_wq: flags=0x8 pwq 2: cpus=0 node=0 flags=0x0 nice=0 active=1 refcnt=2 pending: vmstat_update pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=1 refcnt=2 pending: vmstat_update workqueue writeback: flags=0x4a pwq 8: cpus=0-1 flags=0x4 nice=0 active=1 refcnt=2 pending: wb_workfn workqueue kblockd: flags=0x18 pwq 3: cpus=0 node=0 flags=0x0 nice=-20 active=1 refcnt=2 pending: blk_mq_timeout_work workqueue ipv6_addrconf: flags=0x6000a pwq 8: cpus=0-1 flags=0x4 nice=0 active=1 refcnt=9 in-flight: 73:addrconf_dad_work inactive: 3*addrconf_dad_work, 2*addrconf_verify_work workqueue krxrpcd: flags=0x2001a pwq 9: cpus=0-1 node=0 flags=0x4 nice=-20 active=1 refcnt=10 pending: rxrpc_peer_keepalive_worker inactive: 6*rxrpc_peer_keepalive_worker workqueue bat_events: flags=0x6000a pwq 8: cpus=0-1 flags=0x4 nice=0 active=1 refcnt=38 pending: batadv_iv_send_outstanding_bat_ogm_packet inactive: 5*batadv_iv_send_outstanding_bat_ogm_packet, 5*batadv_mcast_mla_update, batadv_iv_send_outstanding_bat_ogm_packet, 5*batadv_purge_orig, 3*batadv_iv_send_outstanding_bat_ogm_packet, 2*batadv_tt_purge, batadv_dat_purge, 2*batadv_bla_periodic_work, 2*batadv_dat_purge, batadv_bla_periodic_work, 3*batadv_tt_purge, batadv_bla_periodic_work, 2*batadv_dat_purge, batadv_bla_periodic_work workqueue wg-kex-wg0: flags=0x6 pwq 8: cpus=0-1 flags=0x4 nice=0 active=1 refcnt=2 pending: wg_packet_handshake_send_worker pwq 8: cpus=0-1 flags=0x4 nice=0 active=1 refcnt=2 pending: wg_packet_handshake_send_worker workqueue wg-kex-wg1: flags=0x6 pwq 8: cpus=0-1 flags=0x4 nice=0 active=2 refcnt=3 pending: 2*wg_packet_handshake_send_worker workqueue wg-kex-wg2: flags=0x6 pwq 8: cpus=0-1 flags=0x4 nice=0 active=2 refcnt=3 pending: 2*wg_packet_handshake_send_worker workqueue wg-kex-wg0: flags=0x6 pwq 8: cpus=0-1 flags=0x4 nice=0 active=1 refcnt=2 pending: wg_packet_handshake_send_worker pwq 8: cpus=0-1 flags=0x4 nice=0 active=1 refcnt=2 pending: wg_packet_handshake_send_worker workqueue wg-kex-wg1: flags=0x6 pwq 8: cpus=0-1 flags=0x4 nice=0 active=2 refcnt=3 pending: 2*wg_packet_handshake_send_worker workqueue wg-kex-wg2: flags=0x6 pwq 8: cpus=0-1 flags=0x4 nice=0 active=1 refcnt=2 pending: wg_packet_handshake_send_worker pwq 8: cpus=0-1 flags=0x4 nice=0 active=1 refcnt=2 pending: wg_packet_handshake_send_worker workqueue hci0: flags=0x20012 pwq 9: cpus=0-1 node=0 flags=0x4 nice=-20 active=1 refcnt=4 pending: hci_conn_timeout workqueue hci2: flags=0x20012 pwq 9: cpus=0-1 node=0 flags=0x4 nice=-20 active=1 refcnt=4 pending: hci_conn_timeout workqueue bond0: flags=0x2000a pwq 8: cpus=0-1 flags=0x4 nice=0 active=1 refcnt=5 pending: bond_netdev_notify_work inactive: bond_netdev_notify_work workqueue hci1: flags=0x20012 pwq 9: cpus=0-1 node=0 flags=0x4 nice=-20 active=1 refcnt=4 pending: hci_conn_timeout pool 6: cpus=1 node=0 flags=0x0 nice=0 hung=0s workers=9 idle: 5994 12743 14886 16434 12796 6008 5884 5936 pool 7: cpus=1 node=0 flags=0x0 nice=-20 hung=0s workers=3 idle: 6411 16558 pool 8: cpus=0-1 flags=0x4 nice=0 hung=259s workers=23 idle: 14493 1170 10227 10138 1464 13144 10390 1155 3014 3461 13147 2990 45 16167 3489 12 3762 10192 1259 12798 Showing backtraces of running workers in stalled CPU-bound worker pools: