rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4448/1:b..l
(detected by 0, t=10503 jiffies, g=16913, q=140)
task:kworker/u4:7 state:R running task stack:24432 pid: 4448 ppid: 2 flags:0x00004000
Workqueue: bat_events batadv_nc_worker
Call Trace:
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11ef/0x43c0 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:lock_acquire+0x238/0x400 kernel/locking/lockdep.c:5627
Code: 00 00 00 43 c7 44 3d 08 00 00 00 00 65 48 8b 04 25 28 00 00 00 48 3b 84 24 c0 00 00 00 0f 85 f9 00 00 00 48 8d 65 d8 5b 41 5c <41> 5d 41 5e 41 5f 5d c3 0f 0b e9 57 fe ff ff 65 8b 05 f2 75 a5 7e
RSP: 0018:ffffc9000366fb40 EFLAGS: 00000246
RAX: f68dceb216412100 RBX: ffffffff899128c0 RCX: f68dceb216412100
RDX: 0000000000000000 RSI: ffffffff8a2b3a20 RDI: ffffffff8a79f740
RBP: ffffc9000366fb58 R08: dffffc0000000000 R09: 1ffffffff203a418
R10: dffffc0000000000 R11: fffffbfff203a419 R12: ffff88801f3df3d0
R13: 1ffff920006cdf54 R14: 0000000000000246 R15: dffffc0000000000
rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:313
rcu_read_lock include/linux/rcupdate.h:740 [inline]
batadv_nc_process_nc_paths+0xb2/0x350 net/batman-adv/network-coding.c:691
batadv_nc_worker+0x3e5/0x5c0 net/batman-adv/network-coding.c:732
process_one_work+0x85f/0x1010 kernel/workqueue.c:2310
worker_thread+0xaa6/0x1290 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 starved for 10529 jiffies! g16913 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:27352 pid: 15 ppid: 2 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11ef/0x43c0 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/0x11d0 kernel/rcu/tree.c:1972
rcu_gp_kthread+0x9b/0x370 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:
NMI backtrace for cpu 0
CPU: 0 PID: 5097 Comm: syz.0.55 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
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+0x843/0x1120 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+0x4ad/0xb70 kernel/time/hrtimer.c:1749
hrtimer_interrupt+0x3bb/0x8d0 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
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:should_resched arch/x86/include/asm/preempt.h:103 [inline]
RIP: 0010:__local_bh_enable_ip+0x13e/0x1c0 kernel/softirq.c:408
Code: 8a e8 a6 ec 72 08 65 66 8b 05 ae 5b ba 7e 66 85 c0 75 54 bf 01 00 00 00 e8 bf 24 09 00 e8 9a 10 36 00 fb 65 8b 05 5a 32 b9 7e <85> c0 75 05 e8 a9 3f b7 ff 48 c7 04 24 0e 36 e0 45 4b c7 04 37 00
RSP: 0018:ffffc9000333fa80 EFLAGS: 00000282
RAX: 0000000080000000 RBX: 0000000000000200 RCX: e7ce67f91ad7bb00
RDX: dffffc0000000000 RSI: ffffffff8a2b2780 RDI: ffffffff8a79f740
RBP: ffffc9000333fb10 R08: ffff88813fe22407 R09: 1ffff11027fc4480
R10: dffffc0000000000 R11: ffffed1027fc4481 R12: ffffffff812c61e5
R13: ffff88805e42bb80 R14: dffffc0000000000 R15: 1ffff92000667f50
fpregs_unlock arch/x86/include/asm/fpu/api.h:78 [inline]
copy_fpstate_to_sigframe+0x804/0xbf0 arch/x86/kernel/fpu/signal.c:205
get_sigframe arch/x86/kernel/signal.c:295 [inline]
__setup_rt_frame arch/x86/kernel/signal.c:471 [inline]
setup_rt_frame arch/x86/kernel/signal.c:780 [inline]
handle_signal arch/x86/kernel/signal.c:824 [inline]
arch_do_signal_or_restart+0x679/0x12c0 arch/x86/kernel/signal.c:869
handle_signal_work kernel/entry/common.c:154 [inline]
exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
__syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f553e316c80
Code: ef fe ff ff 66 0f 1f 44 00 00 48 8d 3d 6e 8c 1d 00 31 c0 e8 a2 7b ff ff 48 8d 3d e6 8d 1d 00 31 c0 e8 94 7b ff ff 0f 1f 40 00 <41> 57 41 56 41 55 41 54 55 53 48 83 ec 18 48 8b 47 40 48 8b 57 48
RSP: 002b:00007ffec5592cb8 EFLAGS: 00000202
RAX: 0000001b32063fc4 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000001b32063fc3 RSI: 0000000000000008 RDI: 00007f553f202720
RBP: 00007f553f202720 R08: 0000000000000000 R09: 00007f553e6d3038
R10: 0000000000000003 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 000000000000003d