rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5594/2:b..l P161/2:b..l P16561/2:b..l P29 rcu: (detected by 1, t=10502 jiffies, g=109941, q=433 ncpus=2) task:ktimers/1 state:R running task stack:22288 pid:29 tgid:29 ppid:2 task_flags:0x4208040 flags:0x00080000 Call Trace: sched_show_task+0x4aa/0x5f0 kernel/sched/core.c:8140 rcu_print_detail_task_stall_rnp kernel/rcu/tree_stall.h:292 [inline] print_other_cpu_stall+0xf7b/0x1310 kernel/rcu/tree_stall.h:681 check_cpu_stall kernel/rcu/tree_stall.h:856 [inline] rcu_pending kernel/rcu/tree.c:3679 [inline] rcu_sched_clock_irq+0x93d/0x1050 kernel/rcu/tree.c:2716 update_process_times+0x234/0x2d0 kernel/time/timer.c:2475 tick_sched_handle kernel/time/tick-sched.c:298 [inline] tick_nohz_handler+0x3fb/0x730 kernel/time/tick-sched.c:319 __run_hrtimer kernel/time/hrtimer.c:1930 [inline] __hrtimer_run_queues+0x3a0/0xaf0 kernel/time/hrtimer.c:1994 hrtimer_interrupt+0x44a/0x900 kernel/time/hrtimer.c:2113 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] __sysvec_apic_timer_interrupt+0x102/0x430 arch/x86/kernel/apic/apic.c:1067 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1061 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:taprio_set_budgets+0x36b/0x3a0 net/sched/sch_taprio.c:680 Code: c7 40 f6 1a 8f 4c 89 e6 e8 62 79 b1 fb 4c 8b 7c 24 08 e9 3e fe ff ff e8 c3 cf 98 f8 eb 05 e8 bc cf 98 f8 48 83 c4 30 5b 41 5c <41> 5d 41 5e 41 5f 5d c3 cc cc cc cc cc 44 89 f9 80 e1 07 fe c1 38 RSP: 0018:ffffc90000a3fad0 EFLAGS: 00000286 RAX: ffffffff892b37e4 RBX: ffff888038f15800 RCX: ffff88801d2a3d80 RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000100 RBP: ffff888038f15c00 R08: 0000000000000000 R09: 0000000000000100 R10: 0000000000000000 R11: ffffffff8ddc7b60 R12: ffff888038f15800 R13: ffff888072a25000 R14: ffff888072a25380 R15: ffff88803e796036 advance_sched+0x979/0xc90 net/sched/sch_taprio.c:984 __run_hrtimer kernel/time/hrtimer.c:1930 [inline] __hrtimer_run_queues+0x3eb/0xaf0 kernel/time/hrtimer.c:1994 hrtimer_run_softirq+0x18f/0x260 kernel/time/hrtimer.c:2011 handle_softirqs+0x1d9/0x6c0 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] run_ktimerd+0x69/0x100 kernel/softirq.c:1151 smpboot_thread_fn+0x57c/0xa80 kernel/smpboot.c:160 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 task:syz.9.3565 state:R running task stack:24336 pid:16561 tgid:16561 ppid:14662 task_flags:0x40004c flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x16d8/0x55e0 kernel/sched/core.c:7189 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:7370 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 rcu_read_unlock_sched include/linux/rcupdate.h:963 [inline] pfn_valid+0x402/0x480 include/linux/mmzone.h:2291 page_table_check_clear+0x21/0x4f0 mm/page_table_check.c:70 ptep_get_and_clear_full arch/x86/include/asm/jump_label.h:-1 [inline] get_and_clear_full_ptes include/linux/pgtable.h:845 [inline] zap_present_folio_ptes mm/memory.c:1648 [inline] zap_present_ptes mm/memory.c:1730 [inline] do_zap_pte_range mm/memory.c:1832 [inline] zap_pte_range mm/memory.c:1934 [inline] zap_pmd_range mm/memory.c:2020 [inline] zap_pud_range mm/memory.c:2048 [inline] zap_p4d_range mm/memory.c:2069 [inline] __zap_vma_range+0x3769/0x4d20 mm/memory.c:2109 unmap_vmas+0x390/0x550 mm/memory.c:2178 exit_mmap+0x293/0x9f0 mm/mmap.c:1300 __mmput+0xcb/0x3d0 kernel/fork.c:1178 exit_mm+0x1e4/0x2b0 kernel/exit.c:582 do_exit+0x6cd/0x2360 kernel/exit.c:964 do_group_exit+0x22d/0x2f0 kernel/exit.c:1119 __do_sys_exit_group kernel/exit.c:1130 [inline] __se_sys_exit_group kernel/exit.c:1128 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1128 x64_sys_call+0x221a/0x2240 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fcf79aace59 RSP: 002b:00007ffe920d3458 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fcf79aace59 RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007ffe920d34bc R08: 0000000000000000 R09: 00000000000927c0 R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000059 R13: 00000000000927c0 R14: 00000000000e3e11 R15: 00007ffe920d3510 task:kworker/u8:6 state:R running task stack:19896 pid:161 tgid:161 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: bat_events batadv_dat_purge Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x16d8/0x55e0 kernel/sched/core.c:7189 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7513 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x14f/0x8e0 kernel/entry/common.c:164 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_acquire+0x221/0x350 kernel/locking/lockdep.c:5872 Code: ff ff ff e8 01 1d 77 09 f7 44 24 08 00 02 00 00 0f 84 3a ff ff ff 65 48 8b 05 db 07 a8 10 48 3b 44 24 58 75 33 fb 48 83 c4 60 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 00 dd 7a 09 cc 48 8d 3d 38 0e cb RSP: 0018:ffffc90003927980 EFLAGS: 00000282 RAX: 055d93fb5e053700 RBX: 0000000000000000 RCX: 0000000000000046 RDX: 00000000cb681160 RSI: ffffffff8d65af40 RDI: ffffffff8b873ba0 RBP: ffffffff8b195630 R08: ffffffff8b195630 R09: 0000000000000000 R10: 0000000000000000 R11: ffffffff8ddc7b60 R12: 0000000000000002 R13: ffffffff8ddc7b60 R14: 0000000000000000 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:300 [inline] rcu_read_lock include/linux/rcupdate.h:838 [inline] __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline] rt_spin_lock+0x1fc/0x400 kernel/locking/spinlock_rt.c:57 spin_lock_bh include/linux/spinlock_rt.h:90 [inline] __batadv_dat_purge+0x131/0x400 net/batman-adv/distributed-arp-table.c:173 batadv_dat_purge+0x20/0x70 net/batman-adv/distributed-arp-table.c:204 process_one_work kernel/workqueue.c:3314 [inline] process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3397 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3478 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 task:syz-executor state:R running task stack:21776 pid:5594 tgid:5594 ppid:5593 task_flags:0x400100 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x16d8/0x55e0 kernel/sched/core.c:7189 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7513 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x14f/0x8e0 kernel/entry/common.c:164 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:688 RIP: 0010:get_current arch/x86/include/asm/current.h:25 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x8/0x80 kernel/kcov.c:216 Code: 8b 3d 74 48 a6 0b 48 89 de 5b e9 f3 ec 5b 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 8b 04 24 <65> 48 8b 0d 58 e8 83 10 65 8b 35 79 e8 83 10 81 e6 00 00 ff 00 ba RSP: 0018:ffffc900043d7430 EFLAGS: 00000283 RAX: ffffffff8905516a RBX: 1ffff11005177cb0 RCX: ffff888040508000 RDX: 0000000000000000 RSI: 0000000000001000 RDI: 00000000000008ad RBP: 0000000000000200 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: ffffffff8ddc7b60 R12: 1ffff11005177ce0 R13: 0000000000001000 R14: ffffea0000fb3c40 R15: 00000000000008ad __ptr_ring_produce include/linux/ptr_ring.h:114 [inline] page_pool_recycle_in_ring net/core/page_pool.c:791 [inline] page_pool_put_unrefed_netmem+0x72a/0xa40 net/core/page_pool.c:912 page_pool_put_netmem include/net/page_pool/helpers.h:343 [inline] page_pool_put_full_netmem include/net/page_pool/helpers.h:373 [inline] napi_pp_put_page+0x133/0x1e0 net/core/skbuff.c:1028 skb_page_unref include/linux/skbuff_ref.h:40 [inline] __skb_frag_unref include/linux/skbuff_ref.h:56 [inline] skb_release_data+0x3ec/0xab0 net/core/skbuff.c:1108 skb_release_all net/core/skbuff.c:1189 [inline] __napi_kfree_skb net/core/skbuff.c:1482 [inline] kfree_skb_napi_cache net/core/skbuff.c:7283 [inline] skb_attempt_defer_free+0x586/0x7c0 net/core/skbuff.c:7316 tcp_eat_recv_skb net/ipv4/tcp.c:1622 [inline] tcp_recvmsg_locked+0x232c/0x3840 net/ipv4/tcp.c:2900 tcp_recvmsg+0xf6/0x540 net/ipv4/tcp.c:2945 sock_recvmsg_nosec net/socket.c:1140 [inline] sock_recvmsg+0x155/0x1b0 net/socket.c:1160 sock_read_iter+0x24f/0x320 net/socket.c:1230 new_sync_read fs/read_write.c:493 [inline] vfs_read+0x59e/0xa90 fs/read_write.c:574 ksys_read+0x156/0x270 fs/read_write.c:717 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f96086a7fd7 RSP: 002b:00007ffedd20a720 EFLAGS: 00000202 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 000055555a4a1540 RCX: 00007f96086a7fd7 RDX: 00000000000012cc RSI: 000055555a4c3990 RDI: 0000000000000003 RBP: 00007ffedd20ac20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 00000000000012cc R14: 00007ffedd20a810 R15: 000055555a4c3990 rcu: rcu_preempt kthread starved for 8795 jiffies! g109941 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:R running task stack:27328 pid:18 tgid:18 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x16d8/0x55e0 kernel/sched/core.c:7189 __schedule_loop kernel/sched/core.c:7268 [inline] schedule+0x164/0x360 kernel/sched/core.c:7283 schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x30c/0x11f0 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2297 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 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 05/09/2026 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:63 Code: 4b 53 02 e9 43 c4 03 00 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 c3 6c 12 00 fb f4 cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 RSP: 0018:ffffffff8da07dc0 EFLAGS: 00000242 RAX: 0000000000acad91 RBX: ffffffff8199006a RCX: 0000000080000001 RDX: 0000000000000001 RSI: ffffffff8d3fdea3 RDI: ffffffff8b873ba0 RBP: ffffffff8da07eb8 R08: ffff8880b8833e9b R09: 1ffff110171067d3 R10: dffffc0000000000 R11: ffffed10171067d4 R12: 0000000000000000 R13: 1ffffffff1b5fdd8 R14: 0000000000000000 R15: 1ffffffff1b5fdd8 FS: 0000000000000000(0000) GS:ffff8881263a1000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055558b4cba38 CR3: 000000000dbb6000 CR4: 00000000003526f0 Call Trace: arch_safe_halt arch/x86/kernel/process.c:766 [inline] default_idle+0x9/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x72/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:199 [inline] do_idle+0x36a/0x5f0 kernel/sched/idle.c:352 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:451 rest_init+0x2de/0x300 init/main.c:762 start_kernel+0x38a/0x3e0 init/main.c:1220 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310 x86_64_start_kernel+0x137/0x1b0 arch/x86/kernel/head64.c:291 common_startup_64+0x13e/0x147