rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P4992/1:b..l
	(detected by 0, t=10502 jiffies, g=29741, q=41)
task:kworker/u4:17   state:R  running task     stack:22736 pid: 4992 ppid:     2 flags:0x00004000
Workqueue: bat_events batadv_nc_worker
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 kernel/sched/core.c:6395
 preempt_schedule_irq+0xbb/0x160 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:get_current arch/x86/include/asm/current.h:15 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x4/0x60 kernel/kcov.c:205
Code: 00 00 00 00 00 90 53 48 89 fb e8 17 00 00 00 48 8b 3d 70 13 12 0c 48 89 de 5b e9 47 5a 44 00 00 00 cc cc 00 00 cc 48 8b 04 24 <65> 48 8b 0d 04 73 89 7e 65 8b 15 05 73 89 7e 81 e2 00 01 ff 00 74
RSP: 0018:ffffc90003f0fb78 EFLAGS: 00000202
RAX: ffffffff89951fdd RBX: ffffffff899520e0 RCX: 0b8daa06ff5d6700
RDX: 0000000000000000 RSI: ffffffff8a7a41e0 RDI: ffffffff8a7a41a0
RBP: 0000000000000067 R08: dffffc0000000000 R09: 1ffffffff203dc18
R10: dffffc0000000000 R11: fffffbfff203dc19 R12: ffff8881423bfdd0
R13: 0000000000000000 R14: 0000000000000001 R15: ffff88805ef94c80
 rcu_read_unlock include/linux/rcupdate.h:769 [inline]
 batadv_nc_process_nc_paths+0x24d/0x350 net/batman-adv/network-coding.c:703
 batadv_nc_worker+0x3df/0x5c0 net/batman-adv/network-coding.c:732
 process_one_work+0x867/0xff0 kernel/workqueue.c:2310
 worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
rcu: rcu_preempt kthread starved for 10502 jiffies! g29741 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:26896 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2117
 rcu_gp_fqs_loop+0x2be/0x11f0 kernel/rcu/tree.c:1972
 rcu_gp_kthread+0x9a/0x370 kernel/rcu/tree.c:2145
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
NMI backtrace for cpu 0
CPU: 0 PID: 6683 Comm: syz.3.552 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <IRQ>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3a2/0x3d0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline]
 rcu_check_gp_kthread_starvation+0x1cd/0x250 kernel/rcu/tree_stall.h:487
 print_other_cpu_stall+0x1110/0x1270 kernel/rcu/tree_stall.h:592
 check_cpu_stall kernel/rcu/tree_stall.h:745 [inline]
 rcu_pending kernel/rcu/tree.c:3936 [inline]
 rcu_sched_clock_irq+0x845/0x1120 kernel/rcu/tree.c:2619
 update_process_times+0x193/0x200 kernel/time/timer.c:2021
 tick_sched_handle kernel/time/tick-sched.c:254 [inline]
 tick_sched_timer+0x37d/0x560 kernel/time/tick-sched.c:1473
 __run_hrtimer kernel/time/hrtimer.c:1685 [inline]
 __hrtimer_run_queues+0x4b0/0xb60 kernel/time/hrtimer.c:1749
 hrtimer_interrupt+0x397/0x8b0 kernel/time/hrtimer.c:1811
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
 __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x60 kernel/kcov.c:202
Code: 2e 0f 1f 84 00 00 00 00 00 90 53 48 89 fb e8 17 00 00 00 48 8b 3d 70 13 12 0c 48 89 de 5b e9 47 5a 44 00 00 00 cc cc 00 00 cc <48> 8b 04 24 65 48 8b 0d 04 73 89 7e 65 8b 15 05 73 89 7e 81 e2 00
RSP: 0018:ffffc900035d7b38 EFLAGS: 00000202
RAX: ffffffff817bea1e RBX: 0000004f2b07bc40 RCX: ffff88802bef8000
RDX: 0000000000000002 RSI: 0000000000000010 RDI: 0000000000000000
RBP: 0000000000000010 R08: ffff88802bef8000 R09: 0000000000000020
R10: 000000000000001f R11: 0000000000000002 R12: ffff8880736c24d8
R13: dffffc0000000000 R14: 00000000000004c8 R15: 0000000000096510
 rb_event_data_length kernel/trace/ring_buffer.c:176 [inline]
 rb_event_length kernel/trace/ring_buffer.c:204 [inline]
 check_buffer+0x3f7/0x880 kernel/trace/ring_buffer.c:3448
 __rb_reserve_next+0x4d9/0xd00 kernel/trace/ring_buffer.c:3581
 rb_reserve_next_event kernel/trace/ring_buffer.c:3716 [inline]
 ring_buffer_lock_reserve+0xadd/0xed0 kernel/trace/ring_buffer.c:3775
 __trace_buffer_lock_reserve kernel/trace/trace.c:942 [inline]
 trace_event_buffer_lock_reserve+0xd4/0x6a0 kernel/trace/trace.c:2819
 trace_event_buffer_reserve+0x2a8/0x3d0 kernel/trace/trace_events.c:627
 trace_event_raw_event_sys_enter+0x9c/0x140 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: 0033:0x7fce35408d97
Code: 8d 3d 08 9f 0b 00 e8 58 1d fa ff e8 a3 87 00 00 0f 1f 00 b8 68 00 00 00 0f 05 c3 0f 1f 84 00 00 00 00 00 b8 27 00 00 00 0f 05 <c3> 0f 1f 84 00 00 00 00 00 b8 6e 00 00 00 0f 05 c3 0f 1f 84 00 00
RSP: 002b:00007fce33666b08 EFLAGS: 00000202 ORIG_RAX: 0000000000000027
RAX: ffffffffffffffda RBX: 00007fce33666c70 RCX: 00007fce35408d97
RDX: 00007fce33666b40 RSI: 00007fce33666c70 RDI: 0000000000000021
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
R13: 00007fce35697038 R14: 00007ffc4422efd0 R15: 00007ffc4422f0b8
 </TASK>