rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=d45/1/0x4000000000000002 softirq=9561/9563 fqs=22 (detected by 1, t=10502 jiffies, g=11005, q=311) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 5143 Comm: syz.2.62 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 RIP: 0010:rcu_irq_exit+0x1c/0x40 kernel/rcu/tree.c:808 Code: 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 83 3d 9d 5a c0 03 00 0f 84 e3 fe ff ff 65 8b 05 0c 03 59 76 85 c0 0f 85 d4 fe ff ff <65> 8b 05 2d 00 59 76 85 c0 0f 84 c5 fe ff ff 0f 0b e9 be fe ff ff RSP: 0018:ffffc900000075d8 EFLAGS: 00000046 RAX: 0000000000000000 RBX: 1ffff92000000ebc RCX: 0000000000000001 RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000008 RBP: ffffc90000007688 R08: dffffc0000000000 R09: fffffbfff1ad33a6 R10: fffffbfff1ad33a6 R11: 1ffffffff1ad33a5 R12: 0000000000000000 R13: 0000000000000000 R14: dffffc0000000000 R15: 0000000000000802 FS: 00007f088c4776c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b32e63fff CR3: 0000000059bb4000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rcu_irq_exit_irqson+0x8b/0x110 kernel/rcu/tree.c:841 trace_irq_enable_rcuidle+0x11e/0x180 include/trace/events/preemptirq.h:40 trace_hardirqs_on+0x57/0x80 kernel/trace/trace_preemptirq.c:44 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:713 RIP: 0010:rcu_read_unlock_special+0x84/0x480 kernel/rcu/tree_plugin.h:674 Code: f1 f1 f1 00 f2 f2 f2 4a 89 04 2b 66 42 c7 44 2b 09 f3 f3 42 c6 44 2b 0b f3 65 44 8b 35 ed 11 9e 7e 41 f7 c6 00 00 f0 00 74 45 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 66 42 c7 44 2b RSP: 0018:ffffc90000007780 EFLAGS: 00000206 RAX: be413b4e3cfa9100 RBX: 1ffff92000000ef4 RCX: be413b4e3cfa9100 RDX: dffffc0000000000 RSI: ffffffff8a0b1c60 RDI: ffffffff8a59e580 RBP: ffffc90000007860 R08: dffffc0000000000 R09: fffffbfff1ff7c2c R10: fffffbfff1ff7c2c R11: 1ffffffff1ff7c2b R12: ffffffff8c120c00 R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422 rcu_read_unlock include/linux/rcupdate.h:772 [inline] __ip_queue_xmit+0x1244/0x1c00 net/ipv4/ip_output.c:533 __tcp_transmit_skb+0x1ced/0x31c0 net/ipv4/tcp_output.c:1404 tcp_delack_timer_handler+0x32e/0x730 net/ipv4/tcp_timer.c:314 tcp_delack_timer+0x188/0x2e0 net/ipv4/tcp_timer.c:341 call_timer_fn+0x16c/0x530 kernel/time/timer.c:1451 expire_timers kernel/time/timer.c:1496 [inline] __run_timers+0x525/0x7c0 kernel/time/timer.c:1767 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1780 handle_softirqs+0x328/0x820 kernel/softirq.c:576 __do_softirq kernel/softirq.c:610 [inline] invoke_softirq kernel/softirq.c:450 [inline] __irq_exit_rcu+0x12f/0x220 kernel/softirq.c:659 irq_exit_rcu+0x5/0x20 kernel/softirq.c:671 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline] sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:do_futex+0xccb/0x1240 kernel/futex/core.c:3987 Code: 03 38 c1 0f 8c 04 ff ff ff 4c 89 e7 e8 ae 8a 50 00 e9 f7 fe ff ff e8 94 22 0c 00 44 8b 7c 24 18 e9 2d 01 00 00 e8 85 22 0c 00 <8b> 4d 10 48 8b 7c 24 10 89 de 8b 54 24 0c e8 22 0b 00 00 e9 ae 00 RSP: 0018:ffffc90003f3fca0 EFLAGS: 00000293 RAX: ffffffff816ba6d9 RBX: 0000000000000000 RCX: ffff88802a4c1dc0 RDX: 0000000000000000 RSI: ffffffff8c138530 RDI: 0000000000000001 RBP: ffffc90003f3fe08 R08: ffff88802a4c1dc0 R09: 000000000000000d R10: 000000000000000d R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000001 R14: 0000000000000001 R15: 0000000000000000 __do_sys_futex kernel/futex/core.c:4059 [inline] __se_sys_futex+0x3a3/0x430 kernel/futex/core.c:4040 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: 0033:0x7f088ce07fc9 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:00007f088c4770e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: ffffffffffffffda RBX: 00007f088d05efa8 RCX: 00007f088ce07fc9 RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007f088d05efac RBP: 00007f088d05efa0 R08: 00138a07d69f0bfe R09: 0000000000000000 R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f088d05f038 R14: 00007ffe4cd71a90 R15: 00007ffe4cd71b78 rcu: rcu_preempt kthread timer wakeup didn't happen for 10457 jiffies! g11005 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=1 timer-softirq=3317 rcu: rcu_preempt kthread starved for 10458 jiffies! g11005 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27008 pid: 15 ppid: 2 flags:0x00004000 Call Trace: 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 rcu: Stack dump where RCU GP kthread last ran: NMI backtrace for cpu 1 CPU: 1 PID: 5155 Comm: cmp Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Call Trace: dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106 nmi_cpu_backtrace+0x397/0x3d0 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline] rcu_check_gp_kthread_starvation+0x1cd/0x250 kernel/rcu/tree_stall.h:487 print_other_cpu_stall+0x10c8/0x1220 kernel/rcu/tree_stall.h:592 check_cpu_stall kernel/rcu/tree_stall.h:745 [inline] rcu_pending kernel/rcu/tree.c:3936 [inline] rcu_sched_clock_irq+0x831/0x1110 kernel/rcu/tree.c:2619 update_process_times+0x193/0x200 kernel/time/timer.c:1818 tick_sched_handle kernel/time/tick-sched.c:254 [inline] tick_sched_timer+0x37d/0x560 kernel/time/tick-sched.c:1473 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x4fe/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+0x4d/0xc0 arch/x86/kernel/apic/apic.c:1108 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline] RIP: 0010:arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline] RIP: 0010:kvm_wait+0x141/0x190 arch/x86/kernel/kvm.c:918 Code: 89 df 48 89 f8 48 c1 e8 03 42 0f b6 04 30 84 c0 75 47 0f b6 1f e8 1f e2 49 00 44 38 e3 75 10 66 90 0f 00 2d 01 69 d4 08 fb f4 33 ff ff ff fb e9 2d ff ff ff e8 df 65 75 08 89 f9 80 e1 07 38 RSP: 0018:ffffc90000dd08a0 EFLAGS: 00000246 RAX: 378aee2b13f12d00 RBX: 0000000000000003 RCX: 378aee2b13f12d00 RDX: dffffc0000000000 RSI: ffffffff8a0b1c60 RDI: ffffffff8a59e580 RBP: ffffc90000dd0950 R08: dffffc0000000000 R09: fffffbfff1ff7c2c R10: fffffbfff1ff7c2c R11: 1ffffffff1ff7c2b R12: 0000000000000003 R13: ffff8880b913b154 R14: dffffc0000000000 R15: 1ffff920001ba114 pv_wait arch/x86/include/asm/paravirt.h:597 [inline] pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:470 [inline] __pv_queued_spin_lock_slowpath+0x60f/0x9c0 kernel/locking/qspinlock.c:508 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:585 [inline] queued_spin_lock_slowpath+0x43/0x50 arch/x86/include/asm/qspinlock.h:51 queued_spin_lock include/asm-generic/qspinlock.h:85 [inline] do_raw_spin_lock+0x217/0x280 kernel/locking/spinlock_debug.c:115 spin_lock include/linux/spinlock.h:364 [inline] tcp_keepalive_timer+0x2f/0xe30 net/ipv4/tcp_timer.c:714 call_timer_fn+0x16c/0x530 kernel/time/timer.c:1451 expire_timers kernel/time/timer.c:1496 [inline] __run_timers+0x525/0x7c0 kernel/time/timer.c:1767 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1780 handle_softirqs+0x328/0x820 kernel/softirq.c:576 __do_softirq kernel/softirq.c:610 [inline] invoke_softirq kernel/softirq.c:450 [inline] __irq_exit_rcu+0x12f/0x220 kernel/softirq.c:659 irq_exit_rcu+0x5/0x20 kernel/softirq.c:671 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline] sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:debug_spin_lock_after kernel/locking/spinlock_debug.c:93 [inline] RIP: 0010:do_raw_spin_lock+0x130/0x280 kernel/locking/spinlock_debug.c:117 Code: 00 00 00 e8 72 e8 5e 00 48 8d 7c 24 40 be 04 00 00 00 e8 63 e8 5e 00 8b 44 24 40 b9 01 00 00 00 f0 0f b1 0b 0f 85 d9 00 00 00 <65> 8b 1d d1 c7 a4 7e 48 b9 00 00 00 00 00 fc ff df 41 0f b6 04 0f RSP: 0018:ffffc90003f8f800 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffff888074010e78 RCX: 0000000000000001 RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffc90003f8f840 RBP: ffffc90003f8f8b8 R08: 0000000000000004 R09: 0000000000000003 R10: fffff520007f1f08 R11: 1ffff920007f1f08 R12: ffff888074010e88 R13: ffff888074010e80 R14: 1ffff1100e8021d1 R15: 1ffff1100e8021d0 spin_lock include/linux/spinlock.h:364 [inline] browse_rb mm/mmap.c:356 [inline] validate_mm+0x309/0x950 mm/mmap.c:423 __vma_adjust+0x1b6c/0x1c20 mm/mmap.c:1029 vma_adjust include/linux/mm.h:2567 [inline] __split_vma+0x34b/0x410 mm/mmap.c:-1 __do_munmap+0x3eb/0xdc0 mm/mmap.c:2865 do_munmap mm/mmap.c:2910 [inline] munmap_vma_range mm/mmap.c:603 [inline] __mmap_region mm/mmap.c:1757 [inline] mmap_region+0x8bb/0x1660 mm/mmap.c:2933 do_mmap+0x81f/0xea0 mm/mmap.c:1586 vm_mmap_pgoff+0x1b2/0x2b0 mm/util.c:551 ksys_mmap_pgoff+0x542/0x780 mm/mmap.c:1635 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: 0033:0x7f8e91813242 Code: 08 00 04 00 00 eb e2 90 41 f7 c1 ff 0f 00 00 75 27 55 89 cd 53 48 89 fb 48 85 ff 74 33 41 89 ea 48 89 df b8 09 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 5e 5b 5d c3 0f 1f 00 c7 05 46 40 01 00 16 00 RSP: 002b:00007ffcc13e5f18 EFLAGS: 00000206 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007f8e914ef000 RCX: 00007f8e91813242 RDX: 0000000000000003 RSI: 0000000000002000 RDI: 00007f8e914ef000 RBP: 0000000000000812 R08: 0000000000000003 R09: 0000000000006000 R10: 0000000000000812 R11: 0000000000000206 R12: 00007ffcc13e5fd8 R13: 00007f8e914f20c0 R14: 00007ffcc13e6350 R15: 00000fff9827cbe6