rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P1144/1:b..l P5157/1:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=9845, q=454 ncpus=2)
task:udevd           state:R  running task     stack:25160 pid:5157  ppid:1      flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5380 [inline]
 __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
 preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6866
 preempt_schedule+0xab/0xc0 kernel/sched/core.c:6890
 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45
 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline]
 _raw_spin_unlock+0x3a/0x40 kernel/locking/spinlock.c:186
 spin_unlock include/linux/spinlock.h:391 [inline]
 lockref_get_not_dead+0x76/0xb0 lib/lockref.c:190
 __legitimize_path fs/namei.c:711 [inline]
 legitimize_path fs/namei.c:721 [inline]
 legitimize_root fs/namei.c:749 [inline]
 try_to_unlazy+0x288/0x5a0 fs/namei.c:784
 open_last_lookups fs/namei.c:3535 [inline]
 path_openat+0x5b5/0x3190 fs/namei.c:3786
 do_filp_open+0x1c5/0x3d0 fs/namei.c:3816
 do_sys_openat2+0x12c/0x1c0 fs/open.c:1419
 do_sys_open fs/open.c:1434 [inline]
 __do_sys_openat fs/open.c:1450 [inline]
 __se_sys_openat fs/open.c:1445 [inline]
 __x64_sys_openat+0x139/0x160 fs/open.c:1445
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f53d82a7407
RSP: 002b:00007fff36739680 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f53d8a6e880 RCX: 00007f53d82a7407
RDX: 0000000000080141 RSI: 0000562a9295c02e RDI: ffffffffffffff9c
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000000001a4 R11: 0000000000000202 R12: 00000000ffffffff
R13: 00000000ffffffff R14: ffffffffffffffff R15: 0000000000000000
 </TASK>
task:kworker/u4:7    state:R  running task     stack:24432 pid:1144  ppid:2      flags:0x00004000
Workqueue: bat_events batadv_nc_worker
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5380 [inline]
 __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
 preempt_schedule_irq+0xb5/0x140 kernel/sched/core.c:7009
 irqentry_exit+0x67/0x70 kernel/entry/common.c:438
 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:692
RIP: 0010:__preempt_count_add arch/x86/include/asm/preempt.h:80 [inline]
RIP: 0010:rcu_is_watching+0x8/0xb0 kernel/rcu/tree.c:699
Code: e8 0d d4 fe 08 48 c7 c7 80 67 d3 8c 4c 89 f6 e8 9e 1f e2 02 e9 53 ff ff ff 66 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 41 57 41 56 <53> 65 ff 05 08 23 94 7e e8 eb e9 fe 08 89 c3 83 f8 08 73 60 49 bf
RSP: 0000:ffffc9000478fb48 EFLAGS: 00000202
RAX: ffffffff8a36c2d3 RBX: 0000000000000001 RCX: 0000000000000000
RDX: ffff88802397da00 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffff88802fd38520 R08: dffffc0000000000 R09: 1ffffffff21b4ea0
R10: dffffc0000000000 R11: fffffbfff21b4ea1 R12: dffffc0000000000
R13: ffffffff8a36c2a2 R14: ffff888030324c80 R15: 00000000000000a4
 rcu_read_lock include/linux/rcupdate.h:787 [inline]
 batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:408 [inline]
 batadv_nc_worker+0x10c/0x610 net/batman-adv/network-coding.c:719
 process_one_work kernel/workqueue.c:2634 [inline]
 process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711
 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>
rcu: rcu_preempt kthread starved for 10547 jiffies! g9845 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:R  running task     stack:26728 pid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5380 [inline]
 __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
 schedule+0xbd/0x170 kernel/sched/core.c:6773
 schedule_timeout+0x160/0x280 kernel/time/timer.c:2167
 rcu_gp_fqs_loop+0x302/0x1560 kernel/rcu/tree.c:1667
 rcu_gp_kthread+0x99/0x380 kernel/rcu/tree.c:1866
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>
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: 0 Comm: swapper/1 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:148
Code: cc cc cc cc cc cc cc f3 0f 1e fa 0f 0b 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 66 90 0f 00 2d 93 c8 39 00 f3 0f 1e fa fb f4 <c3> cc cc cc cc cc cc cc cc cc cc cc cc 66 0f 1f 00 55 41 57 41 56
RSP: 0018:ffffc90000187de0 EFLAGS: 000002c6
RAX: c83a60476d206b00 RBX: ffffffff816185ab RCX: c83a60476d206b00
RDX: 0000000000000001 RSI: ffffffff8aaabce0 RDI: ffffffff8afc63c0
RBP: ffffc90000187f20 R08: ffff8880b8f36b2b R09: 1ffff110171e6d65
R10: dffffc0000000000 R11: ffffed10171e6d66 R12: ffffffff8e4a82e8
R13: 0000000000000001 R14: 0000000000000001 R15: 1ffff1100364e780
FS:  0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000002a000 CR3: 000000002f7b2000 CR4: 00000000003506e0
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/include/asm/paravirt.h:108 [inline]
 default_idle+0x13/0x20 arch/x86/kernel/process.c:753
 default_idle_call+0x6c/0xa0 kernel/sched/idle.c:97
 cpuidle_idle_call kernel/sched/idle.c:170 [inline]
 do_idle+0x1eb/0x510 kernel/sched/idle.c:282
 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:380
 start_secondary+0xee/0xf0 arch/x86/kernel/smpboot.c:323
 secondary_startup_64_no_verify+0x179/0x17b
 </TASK>