rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (1 GPs behind) idle=4afc/1/0x4000000000000000 softirq=16460/16465 fqs=0
rcu: 	(detected by 0, t=10502 jiffies, g=11685, q=1255 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 36 Comm: kworker/u8:2 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet
RIP: 0010:advance_sched+0x573/0xc90 net/sched/sch_taprio.c:966
Code: 1c f8 48 8b 44 24 70 42 80 3c 20 00 4c 8b 64 24 50 74 08 4c 89 e7 e8 6c db c5 f8 4d 8b 24 24 48 89 df 4c 89 e6 e8 9d 28 60 f8 <4c> 39 e3 75 1b e8 33 26 60 f8 48 bb ff ff ff ff ff ff ff 7f 49 bc
RSP: 0018:ffffc90000a08c70 EFLAGS: 00000006
RAX: ffffffff895fddb3 RBX: 0000000000000000 RCX: ffff88801d2d1e40
RDX: 0000000000010000 RSI: 0000000000001000 RDI: 0000000000000000
RBP: 1ffff11004a7c101 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff5200014117c R12: 0000000000001000
R13: ffff8880253e08c8 R14: ffff8880253e0808 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff888126241000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1ae07e20c0 CR3: 000000002fc08000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 __run_hrtimer kernel/time/hrtimer.c:1777 [inline]
 __hrtimer_run_queues+0x52c/0xc60 kernel/time/hrtimer.c:1841
 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1903
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1041 [inline]
 __sysvec_apic_timer_interrupt+0x10b/0x410 arch/x86/kernel/apic/apic.c:1058
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]
 sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1052
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_acquire+0xb9/0x360 kernel/locking/lockdep.c:5844
Code: 6c a9 df 0d 00 0f 84 fa 00 00 00 65 8b 05 3f de d0 10 85 c0 0f 85 eb 00 00 00 65 48 8b 04 25 08 f0 6d 92 83 b8 2c 0b 00 00 00 <0f> 85 d5 00 00 00 48 c7 44 24 30 00 00 00 00 9c 8f 44 24 30 4c 89
RSP: 0018:ffffc90000ac77c0 EFLAGS: 00000246
RAX: ffff88801d2d1e40 RBX: 0000000000000000 RCX: ca6ba7e402bc2500
RDX: 0000000000000000 RSI: ffffffff8b0f5164 RDI: 1ffffffff1be7a5c
RBP: ffffffff8b0f5140 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed100bfc5517 R12: 0000000000000002
R13: ffffffff8df3d2e0 R14: 0000000000000000 R15: 0000000000000000
 rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 rcu_read_lock include/linux/rcupdate.h:867 [inline]
 batadv_iv_ogm_slide_own_bcast_window net/batman-adv/bat_iv_ogm.c:761 [inline]
 batadv_iv_ogm_schedule_buff net/batman-adv/bat_iv_ogm.c:833 [inline]
 batadv_iv_ogm_schedule+0x454/0xf00 net/batman-adv/bat_iv_ogm.c:873
 batadv_iv_send_outstanding_bat_ogm_packet+0x6c6/0x7e0 net/batman-adv/bat_iv_ogm.c:1709
 process_one_work kernel/workqueue.c:3263 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
rcu: rcu_preempt kthread starved for 10502 jiffies! g11685 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:27112 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5325 [inline]
 __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929
 __schedule_loop kernel/sched/core.c:7011 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:7026
 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083
 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 UID: 0 PID: 5868 Comm: udevd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0xd33/0x12d0 kernel/smp.c:877
Code: 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 b6 73 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 61 6f 0b 00 eb 38 f3 90 <42> 0f b6 04 2b 84 c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 45 6f
RSP: 0018:ffffc90004077580 EFLAGS: 00000293
RAX: ffffffff81b494ab RBX: 1ffff11017127ffd RCX: ffff888032a2dac0
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90004077700 R08: ffffffff8f7ccb77 R09: 1ffffffff1ef996e
R10: dffffc0000000000 R11: fffffbfff1ef996f R12: ffff8880b893ffe8
R13: dffffc0000000000 R14: ffff8880b883b200 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff888126141000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055e647e79a38 CR3: 000000000dd38000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1043
 __flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline]
 flush_tlb_multi arch/x86/mm/tlb.c:1381 [inline]
 flush_tlb_mm_range+0x6b1/0x12d0 arch/x86/mm/tlb.c:1471
 tlb_flush arch/x86/include/asm/tlb.h:23 [inline]
 tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:490 [inline]
 tlb_flush_mmu+0x1a7/0x680 mm/mmu_gather.c:403
 tlb_finish_mmu+0xc3/0x1d0 mm/mmu_gather.c:497
 free_ldt_pgtables+0x17b/0x320 arch/x86/kernel/ldt.c:411
 arch_exit_mmap arch/x86/include/asm/mmu_context.h:234 [inline]
 exit_mmap+0x174/0xb40 mm/mmap.c:1266
 __mmput+0x118/0x430 kernel/fork.c:1133
 exit_mm+0x1da/0x2c0 kernel/exit.c:582
 do_exit+0x648/0x2300 kernel/exit.c:954
 do_group_exit+0x21c/0x2d0 kernel/exit.c:1107
 __do_sys_exit_group kernel/exit.c:1118 [inline]
 __se_sys_exit_group kernel/exit.c:1116 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1116
 x64_sys_call+0x21f7/0x2200 arch/x86/include/generated/asm/syscalls_64.h:232
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2d298f16c5
Code: Unable to access opcode bytes at 0x7f2d298f169b.
RSP: 002b:00007ffe8eb0ee68 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 000055e647fe0550 RCX: 00007f2d298f16c5
RDX: 00000000000000e7 RSI: fffffffffffffe68 RDI: 0000000000000000
RBP: 000055e647e70910 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffe8eb0eeb0 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
sched: DL replenish lagged too much