rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (1 GPs behind) idle=def4/1/0x4000000000000002 softirq=41774/41775 fqs=286
	(detected by 1, t=10505 jiffies, g=59053, q=847 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 11653 Comm: syz.2.2385 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:ksoftirqd_running kernel/softirq.c:91 [inline]
RIP: 0010:invoke_softirq kernel/softirq.c:460 [inline]
RIP: 0010:__irq_exit_rcu+0xe3/0x230 kernel/softirq.c:679
Code: 06 8b 8a e8 6f 87 de 08 65 66 8b 05 57 2c b4 7e 66 85 c0 74 6d 48 c7 c7 e0 06 8b 8a e8 56 87 de 08 65 66 44 8b 35 3d 2c b4 7e <48> c7 c7 e0 06 8b 8a e8 41 87 de 08 65 48 8b 3d 41 02 b3 7e 41 f6
RSP: 0018:ffffc90000007f40 EFLAGS: 00000086
RAX: 0000000000000000 RBX: ffff88801e301dc0 RCX: 74bdc80197af0200
RDX: 1ffffffff1f41c00 RSI: ffffffff8a8b06e0 RDI: ffffffff8adf1320
RBP: ffffc90000007fe0 R08: ffffffff8fa0e008 R09: ffffffff8fa0e018
R10: ffffffff8fa0e010 R11: ffffffff8fa0e003 R12: dffffc0000000000
R13: 0000000000000000 R14: 0000000000000200 R15: 1ffff92000000fe8
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007febec432a90 CR3: 000000005b102000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000008d24 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:691
 instr_sysvec_irq_work arch/x86/kernel/irq_work.c:17 [inline]
 sysvec_irq_work+0x9d/0xc0 arch/x86/kernel/irq_work.c:17
 </IRQ>
 <TASK>
 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:728
RIP: 0010:rcu_read_unlock_special+0x7f/0x510 kernel/rcu/tree_plugin.h:685
Code: eb 03 48 b8 f1 f1 f1 f1 f8 f2 f2 f2 4a 89 04 2b 42 c7 44 2b 08 f8 f3 f3 f3 65 44 8b 35 d2 33 95 7e 41 f7 c6 00 00 f0 00 74 40 <48> c7 44 24 40 0e 36 e0 45 4a c7 04 2b 00 00 00 00 42 c7 44 2b 08
RSP: 0018:ffffc900051ef2a0 EFLAGS: 00000206
RAX: 74bdc80197af0200 RBX: 1ffff92000a3de5c RCX: 74bdc80197af0200
RDX: dffffc0000000000 RSI: ffffffff8a8c1120 RDI: ffffffff8adf1320
RBP: ffffc900051ef398 R08: ffffffff90af9247 R09: 1ffffffff215f248
R10: dffffc0000000000 R11: fffffbfff215f249 R12: 0000000000000246
R13: dffffc0000000000 R14: ffff8880b8e3b900 R15: 0000000000000001
 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:426
 rcu_read_unlock include/linux/rcupdate.h:823 [inline]
 __folio_memcg_unlock+0xea/0x110 mm/memcontrol.c:2151
 page_remove_rmap+0x7e3/0xea0 mm/rmap.c:1462
 zap_pte_range mm/memory.c:1451 [inline]
 zap_pmd_range mm/memory.c:1572 [inline]
 zap_pud_range mm/memory.c:1601 [inline]
 zap_p4d_range mm/memory.c:1622 [inline]
 unmap_page_range+0x114a/0x2500 mm/memory.c:1643
 unmap_vmas+0x260/0x390 mm/memory.c:1728
 exit_mmap+0x20d/0x960 mm/mmap.c:3250
 __mmput+0x118/0x3c0 kernel/fork.c:1205
 exit_mm+0x1fe/0x2d0 kernel/exit.c:565
 do_exit+0x905/0x2480 kernel/exit.c:867
 do_group_exit+0x217/0x2d0 kernel/exit.c:1022
 get_signal+0x1272/0x1350 kernel/signal.c:2871
 arch_do_signal_or_restart+0xc4/0x1350 arch/x86/kernel/signal.c:871
 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7ff73279cdd9
Code: Unable to access opcode bytes at 0x7ff73279cdaf.
RSP: 002b:00007ff733624028 EFLAGS: 00000246 ORIG_RAX: 0000000000000029
RAX: 0000000000000003 RBX: 00007ff732a15fa0 RCX: 00007ff73279cdd9
RDX: 0000000000000084 RSI: 0000000000000001 RDI: 0000000000000002
RBP: 00007ff732832d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff732a16038 R14: 00007ff732a15fa0 R15: 00007ffc88deaf78
 </TASK>
rcu: rcu_preempt kthread starved for 9075 jiffies! g59053 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:26864 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x11d1/0x40e0 kernel/sched/core.c:6562
 schedule+0xb9/0x180 kernel/sched/core.c:6638
 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2168
 rcu_gp_fqs_loop+0x303/0x1340 kernel/rcu/tree.c:1706
 rcu_gp_kthread+0x99/0x3b0 kernel/rcu/tree.c:1905
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 PID: 9459 Comm: kworker/u4:14 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Workqueue: writeback wb_workfn (flush-8:0)
RIP: 0010:native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
RIP: 0010:arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
RIP: 0010:kvm_wait+0x159/0x1b0 arch/x86/kernel/kvm.c:1064
Code: 89 df 48 89 f8 48 c1 e8 03 42 0f b6 04 30 84 c0 75 4b 0f b6 1f e8 47 3b 50 00 44 38 e3 75 10 66 90 0f 00 2d 99 cd 50 09 fb f4 <e9> 16 ff ff ff fb e9 10 ff ff ff e8 87 42 f5 08 89 f9 80 e1 07 38
RSP: 0018:ffffc90003396440 EFLAGS: 00000246
RAX: c7f3d0e8ab204200 RBX: 0000000000000003 RCX: c7f3d0e8ab204200
RDX: dffffc0000000000 RSI: ffffffff8a8c1120 RDI: ffffffff8adf1320
RBP: ffffc900033964f0 R08: ffffffff90af9247 R09: 1ffffffff215f248
R10: dffffc0000000000 R11: fffffbfff215f249 R12: 0000000000000003
R13: ffff8880b8f3b954 R14: dffffc0000000000 R15: 1ffff92000672c88
FS:  0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000559eee06a048 CR3: 00000000342e6000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000008d24 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <TASK>
 pv_wait arch/x86/include/asm/paravirt.h:603 [inline]
 pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:470 [inline]
 __pv_queued_spin_lock_slowpath+0x616/0x9c0 kernel/locking/qspinlock.c:511
 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:591 [inline]
 queued_spin_lock_slowpath+0x43/0x50 arch/x86/include/asm/qspinlock.h:51
 queued_spin_lock include/asm-generic/qspinlock.h:114 [inline]
 do_raw_spin_lock+0x265/0x2f0 kernel/locking/spinlock_debug.c:115
 page_vma_mapped_walk+0x14db/0x1700 mm/page_vma_mapped.c:-1
 page_vma_mkclean_one+0x368/0x6a0 mm/rmap.c:958
 page_mkclean_one+0x1ec/0x3a0 mm/rmap.c:1018
 rmap_walk_file+0x3e8/0x730 mm/rmap.c:2508
 rmap_walk mm/rmap.c:2526 [inline]
 folio_mkclean+0x1e1/0x360 mm/rmap.c:1050
 folio_clear_dirty_for_io+0x203/0xc50 mm/page-writeback.c:2886
 mpage_submit_page+0x8a/0x210 fs/ext4/inode.c:2124
 mpage_process_page_bufs+0x6d8/0x8b0 fs/ext4/inode.c:2258
 mpage_prepare_extent_to_map+0xb34/0x1630 fs/ext4/inode.c:2683
 ext4_writepages+0xab3/0x2f40 fs/ext4/inode.c:2811
 do_writepages+0x3ba/0x640 mm/page-writeback.c:2491
 __writeback_single_inode+0x156/0x1160 fs/fs-writeback.c:1622
 writeback_sb_inodes+0xb30/0x1850 fs/fs-writeback.c:1913
 __writeback_inodes_wb+0x12a/0x3f0 fs/fs-writeback.c:1984
 wb_writeback+0x494/0xd50 fs/fs-writeback.c:2089
 wb_check_old_data_flush fs/fs-writeback.c:2189 [inline]
 wb_do_writeback fs/fs-writeback.c:2242 [inline]
 wb_workfn+0xb68/0xee0 fs/fs-writeback.c:2270
 process_one_work+0x8a2/0x1160 kernel/workqueue.c:2292
 worker_thread+0xaa2/0x1270 kernel/workqueue.c:2439
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>