rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P17019/1:b..l (detected by 1, t=10502 jiffies, g=68793, q=973) task:syz.1.3516 state:R running task stack:25216 pid:17019 ppid: 16036 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_no_mac net/core/filter.c:2161 [inline] __bpf_redirect+0x6ad/0xee0 net/core/filter.c:2184 ____bpf_clone_redirect net/core/filter.c:2455 [inline] bpf_clone_redirect+0x241/0x390 net/core/filter.c:2425 bpf_prog_2f4524d047a4c3c7+0x19/0xf2c bpf_dispatcher_nop_func include/linux/bpf.h:888 [inline] __bpf_prog_run include/linux/filter.h:628 [inline] bpf_prog_run include/linux/filter.h:635 [inline] bpf_test_run+0x292/0x7d0 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: 0033:0x7f7f279e4fc9 RSP: 002b:00007f7f25c2b038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007f7f27c3c090 RCX: 00007f7f279e4fc9 RDX: 0000000000000050 RSI: 00002000000003c0 RDI: 000000000000000a RBP: 00007f7f27a67f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f7f27c3c128 R14: 00007f7f27c3c090 R15: 00007ffd71e572c8 rcu: rcu_preempt kthread timer wakeup didn't happen for 10383 jiffies! g68793 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=37449 rcu: rcu_preempt kthread starved for 10384 jiffies! g68793 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:27200 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: 4405 Comm: kworker/u4:6 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Workqueue: bat_events batadv_nc_worker RIP: 0010:check_preemption_disabled+0x5/0x110 lib/smp_processor_id.c:13 Code: 00 d1 12 8a e8 2c 01 00 00 65 ff 0d 91 f6 59 76 5b c3 00 00 cc 48 c7 c7 20 a8 59 8a 48 c7 c6 60 a8 59 8a eb 00 55 41 57 41 56 <53> 48 83 ec 10 65 48 8b 04 25 28 00 00 00 48 89 44 24 08 65 8b 05 RSP: 0018:ffffc900000073e0 EFLAGS: 00000046 RAX: 0000607f46c34780 RBX: ffffffff8bfeb918 RCX: 000000008a0c1c05 RDX: ffffffff819a60c5 RSI: ffffffff8a59a860 RDI: ffffffff8a59a820 RBP: ffffc900000074f0 R08: dffffc0000000000 R09: fffffbfff1ad334e R10: fffffbfff1ad334e R11: 1ffffffff1ad334d R12: dffffc0000000000 R13: 000000000000000d R14: dffffc0000000000 R15: ffffffff8bfeb8a0 FS: 0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2d923ffc CR3: 00000000220b7000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: perf_trace_lock+0xdf/0x370 include/trace/events/lock.h:39 trace_lock_release include/trace/events/lock.h:58 [inline] lock_release+0x823/0x870 kernel/locking/lockdep.c:5634 __perf_output_begin kernel/events/ring_buffer.c:262 [inline] perf_output_begin_forward+0x793/0xa30 kernel/events/ring_buffer.c:271 __perf_event_output kernel/events/core.c:7804 [inline] perf_event_output_forward+0x15c/0x280 kernel/events/core.c:7822 __perf_event_overflow+0x364/0x530 kernel/events/core.c:9515 perf_swevent_overflow kernel/events/core.c:9591 [inline] perf_swevent_event+0x4ad/0x530 kernel/events/core.c:9629 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:ffs arch/x86/include/asm/bitops.h:297 [inline] RIP: 0010:handle_softirqs+0x1a9/0x820 kernel/softirq.c:564 Code: 24 78 44 89 64 24 28 0f b7 db 48 c7 c7 c0 00 0a 8a e8 5b e7 60 08 65 66 c7 05 51 21 bb 7e 00 00 e8 bc 70 35 00 fb 89 5c 24 34 ff ff ff ff 0f bc 44 24 34 41 89 c5 41 ff c5 0f 85 c1 00 00 00 RSP: 0018:ffffc90000007e20 EFLAGS: 00000282 RAX: 687e385f2c8d2c00 RBX: 0000000000000200 RCX: 687e385f2c8d2c00 RDX: dffffc0000000000 RSI: ffffffff8a0b18a0 RDI: ffffffff8a59a880 RBP: ffffc90000007f30 R08: dffffc0000000000 R09: fffffbfff1ff7a36 R10: fffffbfff1ff7a36 R11: 1ffffffff1ff7a35 R12: 000000000000000a R13: 0000000000000000 R14: ffff88807c70bb80 R15: dffffc0000000000 __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:__rcu_read_unlock+0x73/0xd0 kernel/rcu/tree_plugin.h:422 Code: 84 c0 75 5f 41 83 3e 00 75 20 43 0f b6 04 3c 84 c0 75 3a 8b 03 3d 00 00 00 40 73 0a 5b 41 5c 41 5d 41 5e 41 5f c3 0f 0b eb f2 58 00 00 00 eb d9 89 d9 80 e1 07 80 c1 03 38 c1 7c ac 49 89 fe RSP: 0018:ffffc9000345fbb0 EFLAGS: 00000202 RAX: 0000000000000000 RBX: ffff88807c70bfbc RCX: ffff88807c70bb80 RDX: 0000000000000000 RSI: ffffffff8a59a860 RDI: ffff88807c70bb80 RBP: ffff88807d721d80 R08: dffffc0000000000 R09: fffffbfff1ff7a19 R10: fffffbfff1ff7a19 R11: 1ffffffff1ff7a18 R12: 1ffff1100f8e17f7 R13: fffffffffffffe38 R14: ffff88807c70bfc0 R15: dffffc0000000000 rcu_read_unlock include/linux/rcupdate.h:772 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:416 [inline] batadv_nc_worker+0x256/0x5c0 net/batman-adv/network-coding.c:723 process_one_work+0x863/0x1000 kernel/workqueue.c:2310 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287