rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P4768/1:b..l
	(detected by 0, t=10502 jiffies, g=10625, q=81)
task:syz.4.113       state:R  running task     stack:26176 pid: 4768 ppid:  4185 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11bb/0x4390 kernel/sched/core.c:6395
 preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6799
 irqentry_exit+0x63/0x70 kernel/entry/common.c:432
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:29 [inline]
RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:70 [inline]
RIP: 0010:arch_local_irq_save arch/x86/include/asm/irqflags.h:106 [inline]
RIP: 0010:lock_is_held_type+0x61/0x190 kernel/locking/lockdep.c:5662
Code: 0f 85 f4 00 00 00 65 48 8b 1d 3b ff 58 76 83 bb ec 0a 00 00 00 0f 85 df 00 00 00 41 89 f7 49 89 fe 48 c7 04 24 00 00 00 00 9c <8f> 04 24 4c 8b 2c 24 fa 48 c7 c7 60 2a 0b 8a e8 4b 0e 00 00 65 ff
RSP: 0018:ffffc9000339f728 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffff888074eb1dc0 RCX: ffff888074eb1dc0
RDX: 0000000000000002 RSI: 00000000ffffffff RDI: ffff888076144e10
RBP: 00000000ffffffff R08: dffffc0000000000 R09: fffffbfff1ff7c19
R10: fffffbfff1ff7c19 R11: 1ffffffff1ff7c18 R12: ffff888076144e10
R13: ffffc9000339f878 R14: ffff888076144e10 R15: 00000000ffffffff
 lock_is_held include/linux/lockdep.h:287 [inline]
 xa_head include/linux/xarray.h:1181 [inline]
 xas_start+0x1e5/0x770 lib/xarray.c:188
 xas_load+0x28/0x140 lib/xarray.c:233
 mapping_get_entry mm/filemap.c:1826 [inline]
 pagecache_get_page+0x19d/0xef0 mm/filemap.c:1894
 shmem_getpage_gfp+0x305/0x2d40 mm/shmem.c:1841
 shmem_getpage mm/shmem.c:151 [inline]
 shmem_write_begin+0xcd/0x1a0 mm/shmem.c:2474
 generic_perform_write+0x2aa/0x530 mm/filemap.c:3785
 __generic_file_write_iter+0x25f/0x4e0 mm/filemap.c:3912
 generic_file_write_iter+0xa6/0x1b0 mm/filemap.c:3944
 call_write_iter include/linux/fs.h:2173 [inline]
 new_sync_write fs/read_write.c:507 [inline]
 vfs_write+0x712/0xd00 fs/read_write.c:594
 ksys_write+0x14d/0x250 fs/read_write.c:647
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f4b8864d17f
RSP: 002b:00007f4b86872df0 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000001000000 RCX: 00007f4b8864d17f
RDX: 0000000001000000 RSI: 00007f4b7e453000 RDI: 0000000000000005
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000005f17
R10: 0000000000000770 R11: 0000000000000293 R12: 0000000000000005
R13: 00007f4b86872ef0 R14: 00007f4b86872eb0 R15: 00007f4b7e453000
 </TASK>
rcu: rcu_preempt kthread starved for 10531 jiffies! g10625 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:28064 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11bb/0x4390 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_timeout+0x15c/0x280 kernel/time/timer.c:1914
 rcu_gp_fqs_loop+0x29e/0x11b0 kernel/rcu/tree.c:1972
 rcu_gp_kthread+0x98/0x350 kernel/rcu/tree.c:2145
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 4750 Comm: syz.3.106 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:check_wait_context kernel/locking/lockdep.c:4687 [inline]
RIP: 0010:__lock_acquire+0x635/0x7c60 kernel/locking/lockdep.c:4962
Code: 84 c0 0f 85 bb 62 00 00 83 3d 46 4a b0 14 00 0f 84 b4 01 00 00 31 db 48 81 c3 b9 00 00 00 48 89 d8 48 c1 e8 03 42 0f b6 04 00 <84> c0 0f 85 2f 61 00 00 45 84 f6 0f 84 25 05 00 00 0f b6 1b 48 8b
RSP: 0018:ffffc90000dd0760 EFLAGS: 00000802
RAX: 0000000000000000 RBX: ffffffff8f94d9b9 RCX: ffffffff815c04ed
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8ffbe0d0
RBP: ffffc90000dd09b0 R08: dffffc0000000000 R09: fffffbfff1ff7c1b
R10: fffffbfff1ff7c1b R11: 1ffffffff1ff7c1a R12: ffff88807da146e0
R13: ffff88807da13b80 R14: 0000000000000002 R15: ffff88807da146c0
FS:  00007f053b6cc6c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa0c45df000 CR3: 00000000532e8000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 reacquire_held_locks+0x2f9/0x590 kernel/locking/lockdep.c:5150
 __lock_release kernel/locking/lockdep.c:5339 [inline]
 lock_release+0x31a/0x870 kernel/locking/lockdep.c:5643
 rcu_read_unlock include/linux/rcupdate.h:773 [inline]
 __lock_task_sighand+0x272/0x290 kernel/signal.c:1409
 lock_task_sighand include/linux/sched/signal.h:710 [inline]
 send_sigqueue+0x177/0x620 kernel/signal.c:1975
 posix_timer_event kernel/time/posix-timers.c:360 [inline]
 posix_timer_fn+0x16a/0x3d0 kernel/time/posix-timers.c:386
 __run_hrtimer kernel/time/hrtimer.c:1685 [inline]
 __hrtimer_run_queues+0x53d/0xc40 kernel/time/hrtimer.c:1749
 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1811
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
 __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:202
Code: f6 ff 0f 1f 00 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 de 9e a9 f7 48 89 df e8 a6 73 aa f7 e8 41 0d cb f7 fb bf 01 00 00 00 <e8> 76 95 9e f7 65 8b 05 07 93 4f 76 85 c0 74 02 5b c3 e8 b4 9d 4d
RSP: 0018:ffffc90003a3fbc0 EFLAGS: 00000282
RAX: 3042cf86a2ab2600 RBX: ffff88801afe6f00 RCX: 3042cf86a2ab2600
RDX: dffffc0000000000 RSI: ffffffff8a0b1c60 RDI: 0000000000000001
RBP: 0000000000000000 R08: dffffc0000000000 R09: ffffed10035fcde1
R10: ffffed10035fcde1 R11: 1ffff110035fcde0 R12: ffff88801afe6f00
R13: 0000000000000011 R14: dffffc0000000000 R15: 0000000004000000
 spin_unlock_irq include/linux/spinlock.h:414 [inline]
 get_signal+0x11d6/0x12c0 kernel/signal.c:2903
 arch_do_signal_or_restart+0xc1/0x1300 arch/x86/kernel/signal.c:867
 handle_signal_work kernel/entry/common.c:154 [inline]
 exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f053d4656d2
Code: 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 48 3d 01 f0 ff ff 73 01 c3 <48> c7 c1 a8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84
RSP: 002b:00007f053b6cc0e8 EFLAGS: 00000202
RAX: fffffffffffffffc RBX: 00007f053d6bbfa8 RCX: 00007f053d4656c9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f053d6bbfa8
RBP: 00007f053d6bbfa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f053d6bc038 R14: 00007fff49146490 R15: 00007fff49146578
 </TASK>
vkms_vblank_simulate: vblank timer overrun