GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=827c/1/0x4000000000000000 softirq=109954/109955 fqs=740 rcu: (detected by 1, t=10502 jiffies, g=152741, q=1974 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 7368 Comm: kworker/0:10 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Workqueue: rcu_gp process_srcu RIP: 0010:trace_lock_acquire include/trace/events/lock.h:24 [inline] RIP: 0010:lock_acquire+0xc1/0x420 kernel/locking/lockdep.c:5725 Code: f8 08 0f 83 a0 01 00 00 41 89 c6 c1 e8 06 48 8d 3c c5 68 6e 8c 8e be 08 00 00 00 e8 19 58 77 00 4c 0f a3 35 f9 6a 24 0d 73 0d 5a b3 08 00 84 c0 0f 84 2e 02 00 00 48 c7 c0 1c a3 8c 8e 48 c1 RSP: 0018:ffffc90000007b40 EFLAGS: 00000057 RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff81680367 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8e8c6e68 RBP: ffffc90000007c48 R08: ffffffff8e8c6e6f R09: 1ffffffff1d18dcd R10: dffffc0000000000 R11: fffffbfff1d18dce R12: 1ffff92000000f74 R13: ffffffff97564960 R14: 0000000000000000 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b32019ff8 CR3: 000000006620e000 CR4: 00000000003506f0 Call Trace: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xb4/0x100 kernel/locking/spinlock.c:162 debug_object_deactivate+0x67/0x380 lib/debugobjects.c:764 debug_hrtimer_deactivate kernel/time/hrtimer.c:455 [inline] __run_hrtimer kernel/time/hrtimer.c:1722 [inline] __hrtimer_run_queues+0x2cc/0xc10 kernel/time/hrtimer.c:1818 hrtimer_interrupt+0x39d/0x980 kernel/time/hrtimer.c:1880 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1077 [inline] __sysvec_apic_timer_interrupt+0xfb/0x3b0 arch/x86/kernel/apic/apic.c:1094 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline] sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1088 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:preempt_count_sub+0x10/0x160 kernel/sched/core.c:5873 Code: e8 45 f0 82 00 89 df e9 5b ff ff ff 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 f3 0f 1e fa 55 53 48 bb 00 00 00 00 00 fc ff df <48> c7 c0 80 e4 2e 97 48 c1 e8 03 0f b6 04 18 84 c0 0f 85 bd 00 00 RSP: 0018:ffffc9000b58f9e8 EFLAGS: 00000287 RAX: 000000002ce83b54 RBX: dffffc0000000000 RCX: 0000000000000000 RDX: 000000000000026b RSI: ffffffff8b1cf800 RDI: 0000000000000001 RBP: 0000000000000000 R08: ffff8880b8f43e47 R09: 1ffff110171e87c8 R10: dffffc0000000000 R11: ffffed10171e87c9 R12: 0000000000000002 R13: ffff8880b8f43e40 R14: 0000026b2ce824f8 R15: 000000000000165c delay_tsc+0x4e/0xc0 arch/x86/lib/delay.c:77 try_check_zero+0x39c/0x3e0 kernel/rcu/srcutree.c:1090 srcu_advance_state kernel/rcu/srcutree.c:1692 [inline] process_srcu+0x23b/0x1310 kernel/rcu/srcutree.c:1795 process_one_work kernel/workqueue.c:2653 [inline] process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2730 worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2811 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 rcu: rcu_preempt kthread starved for 9019 jiffies! g152741 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:27848 pid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x15ae/0x4660 kernel/sched/core.c:6700 schedule+0xbd/0x170 kernel/sched/core.c:6774 schedule_timeout+0x188/0x2d0 kernel/time/timer.c:2168 rcu_gp_fqs_loop+0x30d/0x1590 kernel/rcu/tree.c:1667 rcu_gp_kthread+0x9d/0x3b0 kernel/rcu/tree.c:1866 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 PID: 22751 Comm: syz-executor Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:csd_lock_wait kernel/smp.c:311 [inline] RIP: 0010:smp_call_function_many_cond+0xd85/0x1190 kernel/smp.c:855 Code: 45 8b 34 24 44 89 f6 83 e6 01 31 ff e8 34 f1 0a 00 41 83 e6 01 49 be 00 00 00 00 00 fc ff df 75 07 e8 6f ed 0a 00 eb 38 f3 90 <42> 0f b6 04 33 84 c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 53 ed RSP: 0018:ffffc900039f74e0 EFLAGS: 00000293 RAX: ffffffff817bf7fd RBX: 1ffff110171c87a9 RCX: ffff888024d35a00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc900039f7660 R08: ffffc900039f7467 R09: 1ffff9200073ee8c R10: dffffc0000000000 R11: fffff5200073ee8d R12: ffff8880b8e43d48 R13: ffff8880b8f3d3c0 R14: dffffc0000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007efe14826038 CR3: 000000007b0c7000 CR4: 00000000003506e0 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1022 __flush_tlb_multi arch/x86/include/asm/paravirt.h:87 [inline] flush_tlb_multi arch/x86/mm/tlb.c:990 [inline] flush_tlb_mm_range+0x417/0x680 arch/x86/mm/tlb.c:1078 tlb_flush arch/x86/include/asm/tlb.h:20 [inline] tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:474 [inline] tlb_flush_mmu+0x1bd/0x510 mm/mmu_gather.c:300 tlb_finish_mmu+0xf4/0x220 mm/mmu_gather.c:425 exit_mmap+0x428/0xb90 mm/mmap.c:3315 __mmput+0x118/0x3a0 kernel/fork.c:1357 exit_mm+0x23f/0x340 kernel/exit.c:570 do_exit+0x909/0x2530 kernel/exit.c:871 do_group_exit+0x22d/0x2f0 kernel/exit.c:1026 get_signal+0x12a6/0x1390 kernel/signal.c:2903 arch_do_signal_or_restart+0xc2/0x7b0 arch/x86/kernel/signal.c:310 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:291 [inline] syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302 do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7ff25995e68e Code: Unable to access opcode bytes at 0x7ff25995e664. RSP: 002b:00007ffff1a19178 EFLAGS: 00000246 ORIG_RAX: 00000000000000e6 RAX: fffffffffffffdfc RBX: 000055556cbba500 RCX: 00007ff25995e68e RDX: 00007ffff1a191d0 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007ffff1a1923c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000001388 R13: 00000000000927c0 R14: 0000000000125010 R15: 00007ffff1a19290