rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (1 GPs behind) idle=0b4c/1/0x4000000000000000 softirq=18529/18533 fqs=7
rcu: 	(detected by 1, t=10502 jiffies, g=12769, q=1960 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 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 08/18/2025
Workqueue: events_unbound call_usermodehelper_exec_work
RIP: 0010:rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline]
RIP: 0010:rcu_is_watching+0x3a/0xb0 kernel/rcu/tree.c:751
Code: e8 1b c1 d4 09 89 c3 83 f8 08 73 65 49 bf 00 00 00 00 00 fc ff df 4c 8d 34 dd 10 1d be 8d 4c 89 f0 48 c1 e8 03 42 80 3c 38 00 <74> 08 4c 89 f7 e8 4c cd 7c 00 48 c7 c3 98 ff a1 92 49 03 1e 48 89
RSP: 0018:ffffc90000007d20 EFLAGS: 00000046
RAX: 1ffffffff1b7c3a2 RBX: 0000000000000000 RCX: b3dd2189f5af0700
RDX: ffff888020ee5a00 RSI: ffffffff8be33ee0 RDI: ffffffff8be33ea0
RBP: ffffc90000007e90 R08: ffffffff8fa38f37 R09: 1ffffffff1f471e6
R10: dffffc0000000000 R11: fffffbfff1f471e7 R12: ffff888076b31340
R13: 0000000000000000 R14: ffffffff8dbe1d10 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff888125c13000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f23aece3e9c CR3: 000000000df36000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 trace_hrtimer_expire_entry include/trace/events/timer.h:259 [inline]
 __run_hrtimer kernel/time/hrtimer.c:1758 [inline]
 __hrtimer_run_queues+0x475/0xc60 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:lockdep_enabled kernel/locking/lockdep.c:118 [inline]
RIP: 0010:lock_acquire+0x94/0x360 kernel/locking/lockdep.c:5844
Code: 0f 84 d7 01 00 00 83 3d b9 62 06 0e 00 0f 84 f0 00 00 00 48 8b b4 24 90 00 00 00 4c 89 ef e8 93 a5 85 00 83 3d 9c 62 06 0e 00 <0f> 84 fa 00 00 00 65 8b 05 5f b2 03 11 85 c0 0f 85 eb 00 00 00 65
RSP: 0018:ffffc90000ac6d18 EFLAGS: 00000202
RAX: 0000000000000001 RBX: 0000000000000000 RCX: b3dd2189f5af0700
RDX: 0000000000000000 RSI: ffffffff8172c1b2 RDI: 1ffffffff1c2741c
RBP: ffffffff8172c195 R08: 0000000000000000 R09: 0000000000000000
R10: ffffc90000ac6ed8 R11: ffffffff81ac3b00 R12: 0000000000000002
R13: ffffffff8e13a0e0 R14: 0000000000000000 R15: 0000000000000000
 rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 rcu_read_lock include/linux/rcupdate.h:841 [inline]
 class_rcu_constructor include/linux/rcupdate.h:1155 [inline]
 unwind_next_frame+0xc2/0x2390 arch/x86/kernel/unwind_orc.c:479
 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 unpoison_slab_object mm/kasan/common.c:330 [inline]
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:356
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4191 [inline]
 slab_alloc_node mm/slub.c:4240 [inline]
 kmem_cache_alloc_noprof+0x1c1/0x3c0 mm/slub.c:4247
 kmem_alloc_batch lib/debugobjects.c:371 [inline]
 fill_pool+0x100/0x570 lib/debugobjects.c:403
 debug_objects_fill_pool lib/debugobjects.c:725 [inline]
 debug_object_activate+0x383/0x420 lib/debugobjects.c:814
 debug_rcu_head_queue kernel/rcu/rcu.h:236 [inline]
 __call_rcu_common kernel/rcu/tree.c:3108 [inline]
 call_rcu+0xaa/0x9c0 kernel/rcu/tree.c:3243
 free_pids+0xb6/0x100 kernel/pid.c:159
 release_task+0x131b/0x17f0 kernel/exit.c:296
 wait_task_zombie kernel/exit.c:1264 [inline]
 wait_consider_task+0x1944/0x2e10 kernel/exit.c:1491
 do_wait_pid kernel/exit.c:1630 [inline]
 __do_wait+0x541/0x740 kernel/exit.c:1665
 do_wait+0x1f8/0x520 kernel/exit.c:1706
 kernel_wait+0xab/0x170 kernel/exit.c:1882
 call_usermodehelper_exec_sync kernel/umh.c:136 [inline]
 call_usermodehelper_exec_work+0xbe/0x230 kernel/umh.c:163
 process_one_work kernel/workqueue.c:3236 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3319
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
 kthread+0x70e/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x439/0x7d0 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 10488 jiffies! g12769 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:27432 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5357 [inline]
 __schedule+0x1798/0x4cc0 kernel/sched/core.c:6961
 __schedule_loop kernel/sched/core.c:7043 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:7058
 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+0x70e/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x439/0x7d0 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: 1 UID: 101 PID: 5526 Comm: dhcpcd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
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 86 63 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 31 5f 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 15 5f
RSP: 0018:ffffc9000386f560 EFLAGS: 00000293
RAX: ffffffff81b44e7b RBX: 1ffff110170c8349 RCX: ffff88802eaa3c00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc9000386f6e0 R08: ffffffff8fa38f37 R09: 1ffffffff1f471e6
R10: dffffc0000000000 R11: fffffbfff1f471e7 R12: ffff8880b8641a48
R13: dffffc0000000000 R14: ffff8880b873b1c0 R15: 0000000000000000
FS:  00007f331ea00740(0000) GS:ffff888125d13000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff1f7188f50 CR3: 000000007bdbc000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 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+0x6b1/0x12d0 arch/x86/mm/tlb.c:1451
 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
 vms_clear_ptes+0x42c/0x540 mm/vma.c:1235
 vms_complete_munmap_vmas+0x206/0x8a0 mm/vma.c:1277
 do_vmi_align_munmap+0x358/0x420 mm/vma.c:1536
 __do_sys_brk mm/mmap.c:173 [inline]
 __se_sys_brk+0x74e/0xb90 mm/mmap.c:115
 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: 0033:0x7f331eaf96c7
Code: 4d 85 ed 74 e0 4d 85 e4 74 0b 48 89 ef 41 ff d4 4c 89 ee eb da 48 89 f7 e8 e6 1c f3 ff eb f1 0f 1f 40 00 b8 0c 00 00 00 0f 05 <48> 8b 15 6a a7 0d 00 48 89 02 48 39 f8 72 0a 31 c0 c3 0f 1f 80 00
RSP: 002b:00007ffd06fd1e78 EFLAGS: 00000206 ORIG_RAX: 000000000000000c
RAX: ffffffffffffffda RBX: fffffffffffef000 RCX: 00007f331eaf96c7
RDX: fffffffffffff000 RSI: 000056351c78ae50 RDI: 000056351c7ab000
RBP: 000056351c7bc000 R08: 0000000000010150 R09: 0000000000000000
R10: 000056351c64e0f0 R11: 0000000000000206 R12: 00007f331ebdbe50
R13: 0000000000000000 R14: 0000000000001081 R15: 00007f331ebd4ac0
 </TASK>