rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (1 GPs behind) idle=3c54/1/0x4000000000000000 softirq=17065/17072 fqs=0
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P13/1:b.el
rcu: 	(detected by 0, t=10505 jiffies, g=12945, q=1335 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 3435 Comm: kworker/u8:8 Not tainted 6.16.0-syzkaller-06574-gd9104cec3e8f #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Workqueue: ext4-rsv-conversion ext4_end_io_rsv_work
RIP: 0010:advance_sched+0x2aa/0xc90 net/sched/sch_taprio.c:941
Code: 24 48 8d 98 40 01 00 00 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 80 3c 08 00 74 08 48 89 df e8 19 cd 91 f8 48 8b 1b <4c> 89 f7 48 89 de e8 7b ac 2e f8 49 39 de 0f 84 1f 09 00 00 4c 89
RSP: 0018:ffffc90000a08c70 EFLAGS: 00000046
RAX: 1ffff1100e721728 RBX: 0000000000000000 RCX: dffffc0000000000
RDX: 0000000000010000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 0000000000000002 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff5200014117c R12: ffff88806bcdd340
R13: ffff88806bcdd000 R14: 0000002324daacea R15: ffff88807390bc00
FS:  0000000000000000(0000) GS:ffff888125d80000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3e73023ce0 CR3: 000000000df38000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 __run_hrtimer kernel/time/hrtimer.c:1761 [inline]
 __hrtimer_run_queues+0x52c/0xc60 kernel/time/hrtimer.c:1825
 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1887
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline]
 __sysvec_apic_timer_interrupt+0x108/0x410 arch/x86/kernel/apic/apic.c:1056
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1050
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xa8/0x110 kernel/locking/spinlock.c:194
Code: 74 05 e8 6b dd 54 f6 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f6 44 24 21 02 75 4f f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> 13 b6 1d f6 65 8b 05 0c a0 27 07 85 c0 74 40 48 c7 04 24 0e 36
RSP: 0018:ffffc9000b497640 EFLAGS: 00000206
RAX: 95dee4149288d800 RBX: 0000000000000a02 RCX: 95dee4149288d800
RDX: 0000000000000006 RSI: ffffffff8d9790f8 RDI: 0000000000000001
RBP: ffffc9000b4976d0 R08: ffffffff8fa07af7 R09: 1ffffffff1f40f5e
R10: dffffc0000000000 R11: fffffbfff1f40f5f R12: dffffc0000000000
R13: ffffea0001adfc00 R14: ffff88806b8fb490 R15: 1ffff92001692ec8
 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
 __folio_end_writeback+0x7fc/0xc20 mm/page-writeback.c:3039
 folio_end_writeback+0x1a6/0x560 mm/filemap.c:1660
 ext4_finish_bio+0x617/0x9b0 fs/ext4/page-io.c:144
 ext4_release_io_end+0xef/0x2c0 fs/ext4/page-io.c:159
 ext4_end_io_end+0x278/0x410 fs/ext4/page-io.c:210
 ext4_do_flush_completed_IO fs/ext4/page-io.c:287 [inline]
 ext4_end_io_rsv_work+0x262/0x330 fs/ext4/page-io.c:302
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.305 msecs
task:kworker/u8:1    state:R  running task     stack:22984 pid:13    tgid:13    ppid:2      task_flags:0x4208060 flags:0x00004000
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5351 [inline]
 __schedule+0x1737/0x4d30 kernel/sched/core.c:6954
 preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:7138
 preempt_schedule+0xae/0xc0 kernel/sched/core.c:7162
 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
 __local_bh_enable_ip+0x13e/0x1c0 kernel/softirq.c:414
 spin_unlock_bh include/linux/spinlock.h:396 [inline]
 tipc_node_pre_cleanup_net+0x22c/0x350 net/tipc/node.c:3162
 ops_pre_exit_list net/core/net_namespace.c:160 [inline]
 ops_undo_list+0x187/0x990 net/core/net_namespace.c:233
 cleanup_net+0x4c5/0x800 net/core/net_namespace.c:682
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
rcu: rcu_preempt kthread starved for 10505 jiffies! g12945 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:27128 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5351 [inline]
 __schedule+0x1737/0x4d30 kernel/sched/core.c:6954
 __schedule_loop kernel/sched/core.c:7036 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:7051
 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2054
 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2256
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 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: 5506 Comm: dhcpcd Not tainted 6.16.0-syzkaller-06574-gd9104cec3e8f #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:__sanitizer_cov_trace_pc+0x5d/0x70 kernel/kcov.c:235
Code: 18 16 00 00 83 fa 02 75 21 48 8b 91 20 16 00 00 48 8b 32 48 8d 7e 01 8b 89 1c 16 00 00 48 39 cf 73 08 48 89 3a 48 89 44 f2 08 <e9> 0e fc b2 09 cc 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90
RSP: 0018:ffffc900036d7538 EFLAGS: 00000293
RAX: ffffffff81b4451b RBX: 1ffff110170e7f59 RCX: ffff88802cd08000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900036d76c0 R08: ffffffff8fa07af7 R09: 1ffffffff1f40f5e
R10: dffffc0000000000 R11: fffffbfff1f40f5f R12: ffff8880b873fac8
R13: dffffc0000000000 R14: ffff8880b863b180 R15: 0000000000000001
FS:  00007f107f402740(0000) GS:ffff888125c80000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc979981492 CR3: 000000007b16c000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 csd_lock_wait kernel/smp.c:342 [inline]
 smp_call_function_many_cond+0xd4b/0x12d0 kernel/smp.c:877
 on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1044
 __flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline]
 flush_tlb_multi arch/x86/mm/tlb.c:1361 [inline]
 flush_tlb_mm_range+0x6b1/0x12c0 arch/x86/mm/tlb.c:1451
 dup_mmap+0x15a0/0x1ac0 mm/mmap.c:1877
 dup_mm kernel/fork.c:1481 [inline]
 copy_mm+0x13c/0x4b0 kernel/fork.c:1533
 copy_process+0x1706/0x3c00 kernel/fork.c:2172
 kernel_clone+0x21e/0x840 kernel/fork.c:2602
 __do_sys_clone kernel/fork.c:2745 [inline]
 __se_sys_clone kernel/fork.c:2729 [inline]
 __x64_sys_clone+0x18b/0x1e0 kernel/fork.c:2729
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f107f4d6636
Code: 89 df e8 6d e8 f6 ff 45 31 c0 31 d2 31 f6 64 48 8b 04 25 10 00 00 00 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 52 89 c5 85 c0 75 31 64 48 8b 04 25 10 00 00
RSP: 002b:00007ffc07a73bc0 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007ffc07a73bc8 RCX: 00007f107f4d6636
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 00007ffc07a94110 R08: 0000000000000000 R09: 0000000000000001
R10: 00007f107f402a10 R11: 0000000000000246 R12: 00007ffc07a73d00
R13: 0000000000000000 R14: 0000000000000000 R15: 0000563bdcaf7ac0
 </TASK>