rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P9/1:b..l (detected by 0, t=10503 jiffies, g=6089, q=190) task:kworker/u4:0 state:R running task stack:23264 pid: 9 ppid: 2 flags:0x00004000 Workqueue: bat_events batadv_nc_worker Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11bb/0x4390 kernel/sched/core.c:6395 preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6799 irqentry_exit+0x63/0x70 kernel/entry/common.c:432 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:debug_lockdep_rcu_enabled+0x1c/0x30 kernel/rcu/update.c:281 Code: d1 00 00 cc cc 00 00 cc cc 00 00 cc cc 00 31 c0 83 3d bb 49 c7 03 00 74 1d 83 3d 32 7c c7 03 00 74 14 65 48 8b 0d a4 82 60 76 <31> c0 83 b9 ec 0a 00 00 00 0f 94 c0 c3 00 00 cc cc 00 00 cc 41 56 RSP: 0018:ffffc90000ce7bd8 EFLAGS: 00000202 RAX: 0000000000000000 RBX: dffffc0000000000 RCX: ffff88813fed0000 RDX: 0000000000000000 RSI: ffffffff8a0b2e80 RDI: ffffffff8a59e800 RBP: ffff8880248f2c80 R08: dffffc0000000000 R09: fffffbfff1ff5419 R10: fffffbfff1ff5419 R11: 1ffffffff1ff5418 R12: 000000000000004d R13: ffff88807a240268 R14: ffff88807e2f4c80 R15: ffff8880248f2c90 rcu_read_lock include/linux/rcupdate.h:741 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:412 [inline] batadv_nc_worker+0xce/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 rcu: rcu_preempt kthread timer wakeup didn't happen for 3190 jiffies! g6089 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=1 timer-softirq=2192 rcu: rcu_preempt kthread starved for 3193 jiffies! g6089 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=1 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:28064 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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 4422 Comm: syz.1.18 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:__send_signal+0x58d/0xdb0 kernel/signal.c:1182 Code: 00 00 00 fc ff df 80 3c 08 00 74 08 4c 89 ef e8 69 d0 71 00 4d 8b 6d 00 4d 85 ed 0f 85 0c ff ff ff e8 b7 67 2d 00 44 8b 2c 24 <44> 89 ff 48 8b 5c 24 08 48 89 de 8b 54 24 14 e8 df 36 00 00 31 ed RSP: 0018:ffffc90000dd0e18 EFLAGS: 00000006 RAX: ffffffff814a62f1 RBX: 0000000000000010 RCX: ffff88807b8c9dc0 RDX: 0000000000010000 RSI: 0000000000000001 RDI: 0000000000000001 RBP: 0000000000000001 R08: dffffc0000000000 R09: ffff888033d38480 R10: ffffed10067a7095 R11: 1ffff110067a7090 R12: 0000000000000010 R13: 0000000000000000 R14: 0000000000010000 R15: 0000000000000011 FS: 00007f09c192d6c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c32d6f6 CR3: 000000002b037000 CR4: 00000000003526e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: do_send_sig_info kernel/signal.c:1294 [inline] group_send_sig_info+0x1c6/0x220 kernel/signal.c:1442 do_bpf_send_signal+0x7b/0x150 kernel/trace/bpf_trace.c:779 irq_work_single kernel/irq_work.c:155 [inline] irq_work_run_list+0x1bb/0x330 kernel/irq_work.c:177 irq_work_run+0x63/0xe0 kernel/irq_work.c:186 __sysvec_irq_work+0x98/0x240 arch/x86/kernel/irq_work.c:22 instr_sysvec_irq_work arch/x86/kernel/irq_work.c:17 [inline] sysvec_irq_work+0x98/0xc0 arch/x86/kernel/irq_work.c:17 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:713 RIP: 0010:arch_static_branch arch/x86/include/asm/jump_label.h:27 [inline] RIP: 0010:static_key_false include/linux/jump_label.h:212 [inline] RIP: 0010:native_write_msr arch/x86/include/asm/msr.h:156 [inline] RIP: 0010:wrmsr arch/x86/include/asm/msr.h:263 [inline] RIP: 0010:native_apic_msr_write+0x35/0x50 arch/x86/include/asm/apic.h:208 Code: 74 2a 83 ff 30 74 25 eb 10 81 ff d0 00 00 00 74 1b 81 ff e0 00 00 00 74 13 c1 ef 04 81 c7 00 08 00 00 89 f9 89 f0 31 d2 0f 30 <66> 90 c3 89 f6 31 d2 e9 2f bd c7 02 66 2e 0f 1f 84 00 00 00 00 00 RSP: 0018:ffffc90002fbfcb0 EFLAGS: 00000246 RAX: 00000000000000f6 RBX: ffffffff8bbc0a20 RCX: 000000000000083f RDX: 0000000000000000 RSI: 00000000000000f6 RDI: 000000000000083f RBP: 0000000000000000 R08: dffffc0000000000 R09: ffffed10172267af R10: ffffed10172267af R11: 1ffff110172267ae R12: ffff8880b9133b01 R13: dffffc0000000000 R14: dffffc0000000000 R15: 0000000000000020 arch_irq_work_raise+0x82/0xd0 arch/x86/kernel/irq_work.c:31 irq_work_queue+0x95/0x140 kernel/irq_work.c:75 bpf_send_signal_common+0x2b2/0x420 kernel/trace/bpf_trace.c:820 ____bpf_send_signal kernel/trace/bpf_trace.c:829 [inline] bpf_send_signal+0x15/0x20 kernel/trace/bpf_trace.c:827 bpf_prog_7ba5217f62dcd359+0x38/0xa1c 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_trace_run kernel/trace/bpf_trace.c:1878 [inline] bpf_trace_run2+0x15b/0x2d0 kernel/trace/bpf_trace.c:1915 __bpf_trace_sys_enter+0x60/0x70 include/trace/events/syscalls.h:18 trace_sys_enter+0x65/0x80 include/trace/events/syscalls.h:18 syscall_trace_enter+0x115/0x180 kernel/entry/common.c:77 do_syscall_64+0x24/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f09c3ac7829 Code: 64 c7 00 16 00 00 00 b8 ff ff ff ff c3 0f 1f 40 00 90 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 c7 c0 0f 00 00 00 0f 05 <0f> 1f 80 00 00 00 00 48 81 ec 48 01 00 00 49 89 d0 64 48 8b 04 25 RSP: 002b:00007f09c192cb40 EFLAGS: 00000246 ORIG_RAX: 000000000000000f RAX: ffffffffffffffda RBX: 00007f09c3d82278 RCX: 00007f09c3ac7829 RDX: 00007f09c192cb40 RSI: 00007f09c192cc70 RDI: 0000000000000011 RBP: 00007f09c3d82270 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f09c3d82308 R14: 00007ffc96315e80 R15: 00007ffc96315f68