syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (1 GPs behind) idle=422c/1/0x4000000000000000 softirq=15351/15352 fqs=1
rcu: 	(detected by 1, t=10502 jiffies, g=8985, q=823 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 6002 Comm: dhcpcd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:lock_acquire+0x23/0x350 kernel/locking/lockdep.c:5828
Code: 90 90 90 90 90 90 90 f3 0f 1e fa 41 57 4d 89 cf 41 56 41 89 f6 41 55 41 89 d5 41 54 45 89 c4 55 89 cd 53 48 89 fb 48 83 ec 38 <65> 48 8b 05 8d 55 0b 12 48 89 44 24 30 31 c0 66 90 65 8b 05 a9 55
RSP: 0018:ffffc90000007cc0 EFLAGS: 00000086
RAX: 0000000000010002 RBX: ffffffff9ad00b50 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff9ad00b50
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: ffffffff9ad00b38 R12: 0000000000000001
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8881249d8000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000561d3f819660 CR3: 000000007536b000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162
 debug_object_deactivate+0x135/0x3a0 lib/debugobjects.c:873
 debug_hrtimer_deactivate kernel/time/hrtimer.c:443 [inline]
 debug_deactivate kernel/time/hrtimer.c:483 [inline]
 __run_hrtimer kernel/time/hrtimer.c:1745 [inline]
 __hrtimer_run_queues+0x46f/0xad0 kernel/time/hrtimer.c:1841
 hrtimer_interrupt+0x397/0x8e0 kernel/time/hrtimer.c:1903
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1041 [inline]
 __sysvec_apic_timer_interrupt+0x10b/0x3f0 arch/x86/kernel/apic/apic.c:1058
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]
 sysvec_apic_timer_interrupt+0x9f/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:on_stack arch/x86/include/asm/stacktrace.h:60 [inline]
RIP: 0010:stack_access_ok+0x99/0x200 arch/x86/kernel/unwind_orc.c:393
Code: b6 04 02 84 c0 74 08 3c 03 0f 8e 0b 01 00 00 8b 13 85 d2 74 23 49 39 ef 77 1e 48 39 e9 76 19 4a 8d 54 25 00 49 39 d7 0f 92 c0 <48> 39 d1 0f 93 c2 20 d0 0f 85 ba 00 00 00 48 8d 7b 28 48 8d 4b 20
RSP: 0018:ffffc90003aff598 EFLAGS: 00000297
RAX: 0000000000000001 RBX: ffffc90003aff648 RCX: ffffc90003b00000
RDX: ffffc90003affa18 RSI: ffffc90003affa10 RDI: ffffc90003aff648
RBP: ffffc90003affa10 R08: ffffffff91251d58 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000011ae7 R12: 0000000000000008
R13: ffffc90003aff658 R14: ffffc90003aff650 R15: ffffc90003af8000
 deref_stack_reg arch/x86/kernel/unwind_orc.c:403 [inline]
 unwind_next_frame+0xcfe/0x20a0 arch/x86/kernel/unwind_orc.c:585
 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:56
 kasan_record_aux_stack+0xa7/0xc0 mm/kasan/generic.c:559
 slab_free_hook mm/slub.c:2491 [inline]
 slab_free mm/slub.c:6619 [inline]
 kmem_cache_free+0x15e/0x6c0 mm/slub.c:6729
 anon_vma_free mm/rmap.c:136 [inline]
 __put_anon_vma+0x114/0x3a0 mm/rmap.c:2777
 put_anon_vma include/linux/rmap.h:117 [inline]
 unlink_anon_vmas+0x58a/0x820 mm/rmap.c:443
 free_pgtables+0x212/0xc00 mm/memory.c:413
 exit_mmap+0x3f4/0xb90 mm/mmap.c:1291
 __mmput+0x12a/0x410 kernel/fork.c:1133
 mmput+0x62/0x70 kernel/fork.c:1156
 exit_mm kernel/exit.c:582 [inline]
 do_exit+0x7c7/0x2bf0 kernel/exit.c:954
 do_group_exit+0xd3/0x2a0 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+0x3e/0x50 kernel/exit.c:1116
 x64_sys_call+0x150b/0x1730 arch/x86/include/generated/asm/syscalls_64.h:232
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3534ccb6c5
Code: Unable to access opcode bytes at 0x7f3534ccb69b.
RSP: 002b:00007fff47af0358 EFLAGS: 00000206 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f3534ccb6c5
RDX: 00000000000000e7 RSI: ffffffffffffff88 RDI: 0000000000000001
RBP: 00007fff47af0968 R08: 0000561d641932c0 R09: 0000000000000002
R10: 00000000000000e0 R11: 0000000000000206 R12: 00007fff47af03a0
R13: 0000561d641948a0 R14: 00007fff47af05e0 R15: 00007fff47af0390
 </TASK>
rcu: rcu_preempt kthread starved for 10498 jiffies! g8985 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:28120 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5325 [inline]
 __schedule+0x1190/0x5de0 kernel/sched/core.c:6929
 __schedule_loop kernel/sched/core.c:7011 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:7026
 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x1ea/0xaf0 kernel/rcu/tree.c:2083
 rcu_gp_kthread+0x26d/0x380 kernel/rcu/tree.c:2285
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x675/0x7d0 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: 1 UID: 0 PID: 6007 Comm: syz.0.19 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+0xe0f/0x1600 kernel/smp.c:877
Code: 89 54 24 18 49 c1 ed 03 83 e5 07 4d 01 e5 83 c5 03 e8 b5 0c 0c 00 f3 90 41 0f b6 45 00 40 38 c5 7c 08 84 c0 0f 85 e0 05 00 00 <8b> 43 08 31 ff 83 e0 01 41 89 c6 89 c6 e8 cf 07 0c 00 45 85 f6 75
RSP: 0018:ffffc90003adf6f8 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffff8880b8442840 RCX: ffffffff81b13d91
RDX: ffff8880308f4900 RSI: ffffffff81b13d6b RDI: 0000000000000005
RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: dffffc0000000000
R13: ffffed1017088509 R14: 0000000000000001 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888124ad8000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000001b00 CR3: 000000000e182000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 on_each_cpu_cond_mask+0x40/0x90 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+0x4a0/0x17a0 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_tlbonly include/asm-generic/tlb.h:480 [inline]
 tlb_flush_mmu mm/mmu_gather.c:403 [inline]
 tlb_finish_mmu+0x3c9/0x7c0 mm/mmu_gather.c:497
 exit_mmap+0x3fc/0xb90 mm/mmap.c:1293
 __mmput+0x12a/0x410 kernel/fork.c:1133
 mmput+0x62/0x70 kernel/fork.c:1156
 exit_mm kernel/exit.c:582 [inline]
 do_exit+0x7c7/0x2bf0 kernel/exit.c:954
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1107
 get_signal+0x2671/0x26d0 kernel/signal.c:3034
 arch_do_signal_or_restart+0x8f/0x7c0 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop+0x85/0x130 kernel/entry/common.c:40
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
 do_syscall_64+0x426/0xfa0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9c0538efc9
Code: Unable to access opcode bytes at 0x7f9c0538ef9f.
RSP: 002b:00007f9c061f00e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: 0000000000000001 RBX: 00007f9c055e5fa8 RCX: 00007f9c0538efc9
RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007f9c055e5fac
RBP: 00007f9c055e5fa0 R08: 00007f9c061f1000 R09: 0000000000000000
R10: 00000000000000ac R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9c055e6038 R14: 00007fff58facfe0 R15: 00007fff58fad0c8
 </TASK>