GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (1 GPs behind) idle=447c/1/0x4000000000000000 softirq=148827/148827 fqs=0
rcu: 	(detected by 0, t=10505 jiffies, g=161661, q=522 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 133 Comm: kworker/u8:5 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Workqueue: events_unbound call_usermodehelper_exec_work
RIP: 0010:__sanitizer_cov_trace_pc+0x2a/0x70 kernel/kcov.c:235
Code: f3 0f 1e fa 65 8b 05 45 cb 02 12 48 8b 34 24 65 48 8b 15 21 cb 02 12 a9 00 01 ff 00 74 1b f6 c4 01 74 07 a9 00 00 ff 00 74 05 <e9> 11 9c 86 09 8b 82 1c 17 00 00 85 c0 74 f1 8b 82 f8 16 00 00 83
RSP: 0018:ffffc90000a08e30 EFLAGS: 00000046
RAX: 0000000080010002 RBX: 0000000000000001 RCX: ffffffff81f4d23f
RDX: ffff888020bc0000 RSI: ffffffff81f4d24d RDI: ffff888020bc0000
RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000007
R10: 0000000000000001 R11: ffffc90000a08ff8 R12: ffff888034ce1300
R13: 0000000000000000 R14: 0000000000000000 R15: ffff8880b8528690
FS:  0000000000000000(0000) GS:ffff88812445f000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2d21aff8 CR3: 0000000021b2c000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 00000000ffffffff
DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 cpumask_test_cpu include/linux/cpumask.h:649 [inline]
 cpu_online include/linux/cpumask.h:1231 [inline]
 trace_hrtimer_start+0x3d/0x220 include/trace/events/timer.h:223
 debug_activate kernel/time/hrtimer.c:529 [inline]
 enqueue_hrtimer+0x84/0x2f0 kernel/time/hrtimer.c:1109
 __run_hrtimer kernel/time/hrtimer.c:2048 [inline]
 __hrtimer_run_queues+0x6ed/0x9c0 kernel/time/hrtimer.c:2096
 hrtimer_interrupt+0x3e5/0x940 kernel/time/hrtimer.c:2215
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1051 [inline]
 __sysvec_apic_timer_interrupt+0x109/0x470 arch/x86/kernel/apic/apic.c:1068
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
 sysvec_apic_timer_interrupt+0x9e/0xc0 arch/x86/kernel/apic/apic.c:1062
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:179 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0x31/0x80 kernel/locking/spinlock.c:198
Code: f5 53 48 8b 74 24 10 48 89 fb 48 83 c7 18 e8 06 57 55 f6 48 89 df e8 8e a6 55 f6 f7 c5 00 02 00 00 75 23 9c 58 f6 c4 02 75 37 <bf> 01 00 00 00 e8 a5 b4 44 f6 65 8b 05 1e 79 7c 08 85 c0 74 16 5b
RSP: 0018:ffffc90002e37c00 EFLAGS: 00000246
RAX: 0000000000000046 RBX: ffffc90005d2f4f0 RCX: ffffffff8211868f
RDX: 0000000000000000 RSI: ffffffff8c1ce980 RDI: ffffffff8b8f9722
RBP: 0000000000000293 R08: 0000000000000000 R09: fffffbfff21b1e72
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001
R13: ffff888020bc04c4 R14: ffffffff90d92764 R15: 0000000000000000
 umh_complete+0x30/0xa0 kernel/umh.c:55
 call_usermodehelper_exec_sync kernel/umh.c:140 [inline]
 call_usermodehelper_exec_work+0x112/0x180 kernel/umh.c:163
 process_one_work+0xa23/0x1940 kernel/workqueue.c:3314
 process_scheduled_works kernel/workqueue.c:3397 [inline]
 worker_thread+0x5ef/0xe50 kernel/workqueue.c:3478
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
rcu: rcu_preempt kthread starved for 10505 jiffies! g161661 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:28296 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5504 [inline]
 __schedule+0x125c/0x6730 kernel/sched/core.c:7228
 __schedule_loop kernel/sched/core.c:7307 [inline]
 schedule+0xdd/0x390 kernel/sched/core.c:7322
 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2123
 rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2325
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x72b/0xd50 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:
CPU: 0 UID: 0 PID: 25850 Comm: syz.4.5216 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:write_comp_data+0x40/0x90 kernel/kcov.c:246
Code: 02 12 a9 00 01 ff 00 74 1b f6 c4 01 74 07 a9 00 00 ff 00 74 05 c3 cc cc cc cc 8b 87 1c 17 00 00 85 c0 74 f1 8b 87 f8 16 00 00 <83> f8 03 75 e6 48 8b 87 00 17 00 00 8b bf fc 16 00 00 48 8b 30 48
RSP: 0018:ffffc9000609f648 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffffff81fcc34d
RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffff8880335b8000
RBP: ffff8880b8541080 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000003
R13: ffffed10170a8211 R14: 0000000000000001 R15: ffff8880b843c700
FS:  0000000000000000(0000) GS:ffff88812435f000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b30308ff8 CR3: 0000000025db3000 CR4: 00000000003526f0
DR0: ffffffffffffffff DR1: 00000000000001f7 DR2: 00000000ffffffff
DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 csd_lock_wait kernel/smp.c:342 [inline]
 smp_call_function_many_cond+0x5ad/0x16c0 kernel/smp.c:892
 on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1057
 __flush_tlb_multi arch/x86/include/asm/paravirt.h:46 [inline]
 flush_tlb_multi arch/x86/mm/tlb.c:1361 [inline]
 flush_tlb_mm_range+0x45f/0x16f0 arch/x86/mm/tlb.c:1451
 tlb_flush arch/x86/include/asm/tlb.h:23 [inline]
 tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:509 [inline]
 tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:499 [inline]
 tlb_flush_mmu mm/mmu_gather.c:423 [inline]
 tlb_finish_mmu+0x3fe/0x810 mm/mmu_gather.c:549
 exit_mmap+0x454/0xa00 mm/mmap.c:1313
 __mmput+0x12a/0x410 kernel/fork.c:1181
 mmput+0x67/0x80 kernel/fork.c:1204
 exit_mm kernel/exit.c:610 [inline]
 do_exit+0x8b1/0x2ae0 kernel/exit.c:992
 do_group_exit+0xd5/0x2a0 kernel/exit.c:1147
 get_signal+0x1ec7/0x21e0 kernel/signal.c:3038
 arch_do_signal_or_restart+0x91/0x7e0 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline]
 exit_to_user_mode_loop+0x139/0x6f0 kernel/entry/common.c:101
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
 do_syscall_64+0x666/0x870 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4680d9ce59
Code: Unable to access opcode bytes at 0x7f4680d9ce2f.
RSP: 002b:00007f4681ce30e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: 0000000000000001 RBX: 00007f4681015fa8 RCX: 00007f4680d9ce59
RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007f4681015fac
RBP: 00007f4681015fa0 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000030 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4681016038 R14: 00007fff81256710 R15: 00007fff812567f8
 </TASK>