rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (1 GPs behind) idle=8c4c/1/0x4000000000000000 softirq=60465/60477 fqs=4
rcu: 	(detected by 0, t=10502 jiffies, g=35529, q=818 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 10405 Comm: syz.2.1394 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:rb_erase+0x474/0xe60 lib/rbtree.c:444
Code: 74 08 4c 89 ef e8 5c 9b aa f6 4d 89 7d 00 45 31 ed 4c 89 e0 48 c1 e8 03 80 3c 28 00 74 08 4c 89 e7 e8 40 9b aa f6 4d 89 34 24 <4d> 85 ed 0f 84 c1 09 00 00 31 db 48 8b 44 24 18 48 c1 e8 03 48 89
RSP: 0018:ffffc90000a08ca8 EFLAGS: 00000002
RAX: 1ffff110170e4f7a RBX: ffff8880b8727bd0 RCX: dffffc0000000000
RDX: 0000000000010000 RSI: ffff8880b8727bd0 RDI: ffff88807ac12348
RBP: dffffc0000000000 R08: ffffffff8fc3d337 R09: 1ffffffff1f87a66
R10: dffffc0000000000 R11: fffffbfff1f87a67 R12: ffff88807ac12340
R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888125b08000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c41229c CR3: 0000000031904000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000053d850c4
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 rb_erase_cached include/linux/rbtree.h:126 [inline]
 timerqueue_del+0xae/0x100 lib/timerqueue.c:57
 __remove_hrtimer kernel/time/hrtimer.c:1121 [inline]
 __run_hrtimer kernel/time/hrtimer.c:1741 [inline]
 __hrtimer_run_queues+0x364/0xc60 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:its_return_thunk+0x0/0x10 arch/x86/lib/retpoline.S:412
Code: cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc <c3> cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 e9 eb 41 b3 f5 cc
RSP: 0018:ffffc90003bdf2f0 EFLAGS: 00000293
RAX: ffffffff82114081 RBX: ffffea0001fac4c0 RCX: ffff88807d263c00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000001 R08: ffffea0001fac4c7 R09: 1ffffd40003f5898
R10: dffffc0000000000 R11: fffff940003f5899 R12: dffffc0000000000
R13: 0000000000012c58 R14: 0000000000000000 R15: ffffea0001fac4c0
 _compound_head include/linux/page-flags.h:286 [inline]
 __folio_rmap_sanity_checks include/linux/rmap.h:416 [inline]
 __folio_remove_rmap mm/rmap.c:1693 [inline]
 folio_remove_rmap_ptes+0x121/0xfa0 mm/rmap.c:1805
 zap_present_folio_ptes mm/memory.c:1651 [inline]
 zap_present_ptes mm/memory.c:1709 [inline]
 do_zap_pte_range mm/memory.c:1810 [inline]
 zap_pte_range mm/memory.c:1854 [inline]
 zap_pmd_range mm/memory.c:1946 [inline]
 zap_pud_range mm/memory.c:1975 [inline]
 zap_p4d_range mm/memory.c:1996 [inline]
 unmap_page_range+0x1f7f/0x4370 mm/memory.c:2017
 unmap_single_vma mm/memory.c:2060 [inline]
 unmap_vmas+0x399/0x580 mm/memory.c:2104
 exit_mmap+0x248/0xb50 mm/mmap.c:1280
 __mmput+0x118/0x420 kernel/fork.c:1133
 exit_mm+0x1da/0x2c0 kernel/exit.c:582
 do_exit+0x648/0x2300 kernel/exit.c:949
 do_group_exit+0x21c/0x2d0 kernel/exit.c:1102
 get_signal+0x1286/0x1340 kernel/signal.c:3034
 arch_do_signal_or_restart+0x9a/0x750 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop+0x75/0x130 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+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd76138ebe9
Code: Unable to access opcode bytes at 0x7fd76138ebbf.
RSP: 002b:00007fd7622440e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007fd7615b6098 RCX: 00007fd76138ebe9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fd7615b6098
RBP: 00007fd7615b6090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd7615b6128 R14: 00007ffd66ff8c90 R15: 00007ffd66ff8d78
 </TASK>
rcu: rcu_preempt kthread starved for 10492 jiffies! g35529 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:27192 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+0x3f9/0x770 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: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82
Code: d3 e7 02 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 73 e6 2a 00 f3 0f 1e fa fb f4 <c3> cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffffff8e007d80 EFLAGS: 000002c2
RAX: e3f43d3c167cfc00 RBX: ffffffff81968588 RCX: e3f43d3c167cfc00
RDX: 0000000000000001 RSI: ffffffff8c0359e0 RDI: ffffffff81968588
RBP: ffffffff8e007eb8 R08: ffff8880b8632f9b R09: 1ffff110170c65f3
R10: dffffc0000000000 R11: ffffed10170c65f4 R12: ffffffff8fc3d330
R13: 0000000000000000 R14: 0000000000000000 R15: 1ffffffff1c12a38
FS:  0000000000000000(0000) GS:ffff888125a08000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000404030 CR3: 0000000044c92000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
 default_idle+0x13/0x20 arch/x86/kernel/process.c:757
 default_idle_call+0x74/0xb0 kernel/sched/idle.c:122
 cpuidle_idle_call kernel/sched/idle.c:190 [inline]
 do_idle+0x1e8/0x510 kernel/sched/idle.c:330
 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:428
 rest_init+0x2de/0x300 init/main.c:756
 start_kernel+0x3a9/0x410 init/main.c:1109
 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:307
 x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:288
 common_startup_64+0x13e/0x147
 </TASK>