rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (1 GPs behind) idle=13e4/1/0x4000000000000000 softirq=15882/15883 fqs=3
	(detected by 1, t=10502 jiffies, g=20273, q=71 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 5480 Comm: syz.1.289 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:get_current arch/x86/include/asm/current.h:15 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x4/0x60 kernel/kcov.c:215
Code: 00 00 00 00 00 90 53 48 89 fb e8 17 00 00 00 48 8b 3d 30 d9 9e 0c 48 89 de 5b e9 77 62 50 00 00 00 cc cc 00 00 cc 48 8b 04 24 <65> 48 8b 0d 44 3b 80 7e 65 8b 15 45 3b 80 7e 81 e2 00 01 ff 00 74
RSP: 0018:ffffc90000007cc8 EFLAGS: 00000002
RAX: ffffffff886733a8 RBX: ffffffff886732e4 RCX: 18ab16b64dfdce00
RDX: ffff88802c731e00 RSI: ffffffff8adf5dc0 RDI: ffffffff8adf5d80
RBP: 0000000000000001 R08: ffff88807663315f R09: 1ffff1100ecc662b
R10: dffffc0000000000 R11: ffffed100ecc662c R12: 18c588358e4b41f1
R13: dffffc0000000000 R14: ffff888028998500 R15: ffff888076633000
FS:  00007fa1b8a726c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f17791b3d58 CR3: 000000002f3e7000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 rcu_read_unlock include/linux/rcupdate.h:820 [inline]
 advance_sched+0x778/0x950 net/sched/sch_taprio.c:761
 __run_hrtimer kernel/time/hrtimer.c:1751 [inline]
 __hrtimer_run_queues+0x522/0xc90 kernel/time/hrtimer.c:1815
 hrtimer_interrupt+0x399/0x980 kernel/time/hrtimer.c:1877
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1107 [inline]
 __sysvec_apic_timer_interrupt+0x153/0x5a0 arch/x86/kernel/apic/apic.c:1124
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
 sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1118
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xbc/0x120 kernel/locking/spinlock.c:194
Code: c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f7 44 24 20 00 02 00 00 41 c6 04 07 f8 75 4b f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> 3f 89 1e f7 65 8b 05 b0 3a c8 75 85 c0 74 3c 48 c7 04 24 0e 36
RSP: 0018:ffffc9000517f5e0 EFLAGS: 00000206
RAX: dffffc0000000004 RBX: 0000000000000a02 RCX: 18ab16b64dfdce00
RDX: dffffc0000000000 RSI: ffffffff8a8c17a0 RDI: 0000000000000001
RBP: ffffc9000517f678 R08: ffffffff90b0f2ef R09: 1ffffffff2161e5d
R10: dffffc0000000000 R11: fffffbfff2161e5e R12: dffffc0000000000
R13: ffff88802f9311d0 R14: ffff88802f9311d0 R15: 1ffff92000a2febc
 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
 __skb_try_recv_datagram+0x17d/0x4e0 net/core/datagram.c:265
 __unix_dgram_recvmsg+0x2f5/0xd90 net/unix/af_unix.c:2451
 ____sys_recvmsg+0x2c8/0x5b0 net/socket.c:-1
 ___sys_recvmsg+0x210/0x590 net/socket.c:2780
 do_recvmmsg+0x370/0x810 net/socket.c:2874
 __sys_recvmmsg net/socket.c:2953 [inline]
 __do_sys_recvmmsg net/socket.c:2976 [inline]
 __se_sys_recvmmsg net/socket.c:2969 [inline]
 __x64_sys_recvmmsg+0x195/0x250 net/socket.c:2969
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fa1b7b9de99
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fa1b8a72028 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00007fa1b7e26090 RCX: 00007fa1b7b9de99
RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000005
RBP: 00007fa1b7c33eaf R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa1b7e26128 R14: 00007fa1b7e26090 R15: 00007fff864cbba8
 </TASK>
rcu: rcu_preempt kthread starved for 10496 jiffies! g20273 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:27888 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5246 [inline]
 __schedule+0x107f/0x4030 kernel/sched/core.c:6563
 schedule+0xb9/0x180 kernel/sched/core.c:6639
 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2168
 rcu_gp_fqs_loop+0x303/0x1350 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: 9 Comm: kworker/u4:0 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:check_kcov_mode kernel/kcov.c:193 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x32/0x60 kernel/kcov.c:216
Code: 44 3b 80 7e 65 8b 15 45 3b 80 7e 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 1c 16 00 00 00 74 2c 8b 91 f8 15 00 00 <83> fa 02 75 21 48 8b 91 00 16 00 00 48 8b 32 48 8d 7e 01 8b 89 fc
RSP: 0018:ffffc900000e77f8 EFLAGS: 00000246
RAX: ffffffff81773813 RBX: dffffc0000000000 RCX: ffff88813fe70000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900000e7960 R08: ffffffff90b0f247 R09: 1ffffffff2161e48
R10: dffffc0000000000 R11: fffffbfff2161e49 R12: 1ffff110171c8641
R13: ffff8880b8f3bdc0 R14: 0000000000000000 R15: ffff8880b8e43208
FS:  0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa1b7beb580 CR3: 000000000c88e000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 csd_lock_wait kernel/smp.c:424 [inline]
 smp_call_function_many_cond+0x1163/0x1250 kernel/smp.c:998
 on_each_cpu_cond_mask+0x3b/0x80 kernel/smp.c:1165
 on_each_cpu include/linux/smp.h:71 [inline]
 text_poke_sync arch/x86/kernel/alternative.c:1574 [inline]
 text_poke_bp_batch+0x2b7/0x850 arch/x86/kernel/alternative.c:1774
 text_poke_flush arch/x86/kernel/alternative.c:1965 [inline]
 text_poke_finish+0x16/0x30 arch/x86/kernel/alternative.c:1972
 arch_jump_label_transform_apply+0x13/0x20 arch/x86/kernel/jump_label.c:146
 static_key_enable_cpuslocked+0x11f/0x240 kernel/jump_label.c:207
 static_key_enable+0x16/0x20 kernel/jump_label.c:220
 toggle_allocation_gate+0xba/0x470 mm/kfence/core.c:821
 process_one_work+0x8ab/0x1160 kernel/workqueue.c:2292
 worker_thread+0xaf5/0x12a0 kernel/workqueue.c:2439
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
vkms_vblank_simulate: vblank timer overrun