vkms_vblank_simulate: vblank timer overrun
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P27321/1:b..l
rcu: 	(detected by 1, t=10502 jiffies, g=198589, q=883 ncpus=2)
task:syz.6.5625      state:R  running task     stack:24072 pid:27321 tgid:27321 ppid:25360  task_flags:0x40004c flags:0x00080001
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5325 [inline]
 __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929
 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7256
 irqentry_exit+0x6f/0x90 kernel/entry/common.c:211
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:orc_ip arch/x86/kernel/unwind_orc.c:80 [inline]
RIP: 0010:__orc_find arch/x86/kernel/unwind_orc.c:102 [inline]
RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:227 [inline]
RIP: 0010:unwind_next_frame+0x130e/0x2390 arch/x86/kernel/unwind_orc.c:494
Code: c1 e8 3f 48 01 c8 48 83 e0 fe 4c 8d 3c 45 00 00 00 00 49 01 ef 4c 89 f8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 0f b6 04 08 <84> c0 75 27 49 63 07 4c 01 f8 49 8d 4f 04 4c 39 e0 48 0f 46 e9 49
RSP: 0018:ffffc9000c1f6fb8 EFLAGS: 00000a02
RAX: 0000000000000000 RBX: ffffffff8f933ecc RCX: dffffc0000000000
RDX: ffffffff8f933e9c RSI: ffffffff900f1890 RDI: ffffffff8bbf0700
RBP: ffffffff8f933ec4 R08: 000000000000000d R09: ffffffff81738d25
R10: ffffc9000c1f70d8 R11: ffffffff81ac2f50 R12: ffffffff81ac2efb
R13: ffffffff8f933ec0 R14: ffffc9000c1f7088 R15: ffffffff8f933ec8
 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 save_stack+0xf5/0x1f0 mm/page_owner.c:156
 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:311
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1394 [inline]
 free_unref_folios+0xdb3/0x14f0 mm/page_alloc.c:2963
 folios_put_refs+0x584/0x670 mm/swap.c:1002
 folio_batch_release include/linux/pagevec.h:101 [inline]
 shmem_undo_range+0x49e/0x14b0 mm/shmem.c:1120
 shmem_truncate_range mm/shmem.c:1232 [inline]
 shmem_evict_inode+0x272/0xa70 mm/shmem.c:1360
 evict+0x504/0x9c0 fs/inode.c:810
 __dentry_kill+0x209/0x660 fs/dcache.c:669
 dput+0x19f/0x2b0 fs/dcache.c:911
 __fput+0x68e/0xa70 fs/file_table.c:476
 task_work_run+0x1d4/0x260 kernel/task_work.c:227
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x6b5/0x2300 kernel/exit.c:966
 do_group_exit+0x21c/0x2d0 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+0x3f/0x40 kernel/exit.c:1116
 x64_sys_call+0x21f7/0x2200 arch/x86/include/generated/asm/syscalls_64.h:232
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f12eb98efc9
RSP: 002b:00007f12ebd0fd88 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f12eb98efc9
RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f12ebd0fdec R08: 00000019ebd0fe7f R09: 00000000000927c0
R10: 00000000000001b0 R11: 0000000000000246 R12: 000000000000005e
R13: 00000000000927c0 R14: 0000000000176ac9 R15: 00007f12ebd0fe40
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10541 jiffies! g198589 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=0 timer-softirq=128400
rcu: rcu_preempt kthread starved for 10542 jiffies! g198589 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27336 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5325 [inline]
 __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929
 __schedule_loop kernel/sched/core.c:7011 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:7026
 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+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x4bc/0x870 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:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 27341 Comm: syz.4.5629 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:debug_lockdep_rcu_enabled+0x21/0x40 kernel/rcu/update.c:321
Code: 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 31 c0 83 3d a7 94 36 04 00 74 1e 83 3d aa c3 36 04 00 74 15 65 48 8b 0c 25 08 30 6e 92 <31> c0 83 b9 2c 0b 00 00 00 0f 94 c0 c3 cc cc cc cc cc cc cc cc cc
RSP: 0018:ffffc9000b4eeff8 EFLAGS: 00000202
RAX: 0000000000000000 RBX: 00000000ffff0000 RCX: ffff88807aa85ac0
RDX: ffff88807aa85ac0 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 0000000000000001 R08: ffff88807aa85ac0 R09: 0000000000000002
R10: 00000000ffffffff R11: 0000000000000000 R12: ffff88807c259038
R13: dffffc0000000000 R14: ffff88804896e000 R15: ffff888027f1c480
FS:  00007f915ea9d6c0(0000) GS:ffff88812613d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000770 CR3: 00000000585f8000 CR4: 00000000003526f0
DR0: 0000000000000008 DR1: 0000000000000002 DR2: 0000000000000081
DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 rcu_read_lock_held_common kernel/rcu/update.c:105 [inline]
 rcu_read_lock_held+0xa/0x50 kernel/rcu/update.c:349
 qdisc_lookup_rcu+0x381/0x6d0 net/sched/sch_api.c:333
 qdisc_tree_reduce_backlog+0x1b2/0x480 net/sched/sch_api.c:795
 fq_codel_change+0x9f6/0xda0 net/sched/sch_fq_codel.c:454
 fq_codel_init+0x355/0x970 net/sched/sch_fq_codel.c:489
 qdisc_create+0x7ac/0xea0 net/sched/sch_api.c:1319
 __tc_modify_qdisc net/sched/sch_api.c:1748 [inline]
 tc_modify_qdisc+0x1538/0x20e0 net/sched/sch_api.c:1812
 rtnetlink_rcv_msg+0x77c/0xb70 net/core/rtnetlink.c:6960
 netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2552
 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
 netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1346
 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1896
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg+0x21c/0x270 net/socket.c:742
 ____sys_sendmsg+0x505/0x830 net/socket.c:2630
 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2684
 __sys_sendmsg net/socket.c:2716 [inline]
 __do_sys_sendmsg net/socket.c:2721 [inline]
 __se_sys_sendmsg net/socket.c:2719 [inline]
 __x64_sys_sendmsg+0x19b/0x260 net/socket.c:2719
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f915db8efc9
Code: ff ff c3 66 2e 0f 1f 84 00 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
RSP: 002b:00007f915ea9d038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f915dde6090 RCX: 00007f915db8efc9
RDX: 0000000000000000 RSI: 0000200000000740 RDI: 0000000000000004
RBP: 00007f915dc11f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f915dde6128 R14: 00007f915dde6090 R15: 00007f915df0fa28
 </TASK>
vkms_vblank_simulate: vblank timer overrun