rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P9954/1:b..l (detected by 1, t=10502 jiffies, g=31949, q=889) task:syz.0.1527 state:R running task stack:26184 pid: 9954 ppid: 8946 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11bb/0x4390 kernel/sched/core.c:6395 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6571 preempt_schedule+0xa7/0xb0 kernel/sched/core.c:6596 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34 __local_bh_enable_ip+0x13b/0x1b0 kernel/softirq.c:408 rcu_read_unlock_bh include/linux/rcupdate.h:810 [inline] __dev_queue_xmit+0x1bc5/0x2ed0 net/core/dev.c:4315 __bpf_tx_skb net/core/filter.c:2127 [inline] __bpf_redirect_common net/core/filter.c:2175 [inline] __bpf_redirect+0xa46/0xee0 net/core/filter.c:2182 ____bpf_clone_redirect net/core/filter.c:2455 [inline] bpf_clone_redirect+0x241/0x390 net/core/filter.c:2425 bpf_prog_c6f54bbad6dab1ee+0x56/0x2fc bpf_dispatcher_nop_func include/linux/bpf.h:888 [inline] __bpf_prog_run include/linux/filter.h:621 [inline] bpf_prog_run include/linux/filter.h:635 [inline] bpf_test_run+0x498/0x7d0 net/bpf/test_run.c:119 bpf_prog_test_run_skb+0x9cc/0x1180 net/bpf/test_run.c:669 bpf_prog_test_run+0x31e/0x390 kernel/bpf/syscall.c:3374 __sys_bpf+0x535/0x670 kernel/bpf/syscall.c:4675 __do_sys_bpf kernel/bpf/syscall.c:4761 [inline] __se_sys_bpf kernel/bpf/syscall.c:4759 [inline] __x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:4759 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f15b2d33749 RSP: 002b:00007f15b0f9a038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007f15b2f89fa0 RCX: 00007f15b2d33749 RDX: 0000000000000050 RSI: 0000200000000380 RDI: 000000000000000a RBP: 00007f15b2db7f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f15b2f8a038 R14: 00007f15b2f89fa0 R15: 00007ffe84c3e118 rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g31949 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=20814 rcu: rcu_preempt kthread starved for 10502 jiffies! g31949 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:27232 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11bb/0x4390 kernel/sched/core.c:6395 schedule+0x11b/0x1e0 kernel/sched/core.c:6478 schedule_timeout+0x15c/0x280 kernel/time/timer.c:1914 rcu_gp_fqs_loop+0x29e/0x11b0 kernel/rcu/tree.c:1972 rcu_gp_kthread+0x98/0x350 kernel/rcu/tree.c:2145 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 9958 Comm: syz.7.1529 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:cpu_max_bits_warn include/linux/cpumask.h:108 [inline] RIP: 0010:cpumask_check include/linux/cpumask.h:115 [inline] RIP: 0010:cpumask_test_cpu include/linux/cpumask.h:344 [inline] RIP: 0010:cpu_online include/linux/cpumask.h:895 [inline] RIP: 0010:irq_work_queue_on+0x19/0x220 kernel/irq_work.c:95 Code: 02 e9 42 ff ff ff 66 2e 0f 1f 84 00 00 00 00 00 90 55 41 57 41 56 41 55 41 54 53 89 f5 48 89 fb e8 4c 39 f4 ff bf 07 00 00 00 <89> ee e8 a0 3c f4 ff 83 fd 07 0f 87 62 01 00 00 e8 32 39 f4 ff 41 RSP: 0018:ffffc90000007228 EFLAGS: 00000046 RAX: ffffffff818392c4 RBX: ffff8880b903b1f0 RCX: ffff88802771bb80 RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000007 RBP: 0000000000000000 R08: dffffc0000000000 R09: ffff8880b903b1f0 R10: ffffed1017207640 R11: 1ffff1101720763e R12: ffff8880b903b208 R13: dffffc0000000000 R14: ffff8880b903b200 R15: 1ffff11017207641 FS: 00007facef87d6c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c341aa0 CR3: 000000007c8b3000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000200000000300 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: rcu_read_unlock_special+0x379/0x480 kernel/rcu/tree_plugin.h:667 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422 rcu_read_unlock include/linux/rcupdate.h:772 [inline] __perf_event_output kernel/events/core.c:7813 [inline] perf_event_output_forward+0x216/0x280 kernel/events/core.c:7822 __perf_event_overflow+0x364/0x530 kernel/events/core.c:9515 perf_tp_event+0x32c/0xb50 kernel/events/core.c:10047 perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10021 perf_trace_preemptirq_template+0x2be/0x380 include/trace/events/preemptirq.h:14 trace_irq_enable_rcuidle+0x108/0x180 include/trace/events/preemptirq.h:40 trace_hardirqs_on+0x57/0x80 kernel/trace/trace_preemptirq.c:44 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:713 RIP: 0010:rcu_read_unlock_special+0x84/0x480 kernel/rcu/tree_plugin.h:674 Code: f1 f1 f1 00 f2 f2 f2 4a 89 04 2b 66 42 c7 44 2b 09 f3 f3 42 c6 44 2b 0b f3 65 44 8b 35 ed 11 9e 7e 41 f7 c6 00 00 f0 00 74 45 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 66 42 c7 44 2b RSP: 0018:ffffc900000079e0 EFLAGS: 00000206 RAX: 3f1929ae627fa900 RBX: 1ffff92000000f40 RCX: 3f1929ae627fa900 RDX: dffffc0000000000 RSI: ffffffff8a0b1be0 RDI: ffffffff8a59e800 RBP: ffffc90000007ac0 R08: dffffc0000000000 R09: fffffbfff1ff5438 R10: fffffbfff1ff5438 R11: 1ffffffff1ff5437 R12: ffffffff8c120c00 R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422 rcu_read_unlock include/linux/rcupdate.h:772 [inline] hsr_announce+0x294/0x300 net/hsr/hsr_device.c:410 call_timer_fn+0x16c/0x530 kernel/time/timer.c:1451 expire_timers kernel/time/timer.c:1496 [inline] __run_timers+0x525/0x7c0 kernel/time/timer.c:1767 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1780 handle_softirqs+0x328/0x820 kernel/softirq.c:576 __do_softirq kernel/softirq.c:610 [inline] invoke_softirq kernel/softirq.c:450 [inline] __irq_exit_rcu+0x12f/0x220 kernel/softirq.c:659 irq_exit_rcu+0x5/0x20 kernel/softirq.c:671 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline] sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:__syscall_enter_from_user_work kernel/entry/common.c:93 [inline] RIP: 0010:syscall_enter_from_user_mode+0x2a/0x70 kernel/entry/common.c:114 Code: 41 56 53 48 89 f3 49 89 fe 48 8b 7c 24 10 e8 3d f6 ff ff eb 31 eb 35 e8 74 f9 db f7 e8 6f f7 db f7 fb 65 48 8b 05 36 7d 60 76 <48> 8b 70 08 40 f6 c6 3f 74 0b 4c 89 f7 5b 41 5e e9 21 3b c4 f7 48 RSP: 0018:ffffc90002f6ff08 EFLAGS: 00000286 RAX: ffff88802771bb80 RBX: 00000000000000ca RCX: 3f1929ae627fa900 RDX: dffffc0000000000 RSI: ffffffff8a0b1be0 RDI: ffffffff8a59e800 RBP: ffffc90002f6ff48 R08: dffffc0000000000 R09: ffffed1017207662 R10: ffffed1017207662 R11: 1ffff11017207661 R12: 0000000000000000 R13: 0000000000000000 R14: ffffc90002f6ff58 R15: 0000000000000000 do_syscall_64+0x24/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7facf1616749 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007facef87d0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: ffffffffffffffda RBX: 00007facf186cfa8 RCX: 00007facf1616749 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007facf186cfa8 RBP: 00007facf186cfa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007facf186d038 R14: 00007ffc143d21c0 R15: 00007ffc143d22a8