rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: (detected by 0, t=10502 jiffies, g=6697, q=6 ncpus=2) rcu: All QSes seen, last rcu_preempt kthread activity 10501 (4294970106-4294959605), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 10502 jiffies! g6697 f0x2 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:26256 pid:16 tgid:16 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5409 [inline] __schedule+0x17d3/0x4a20 kernel/sched/core.c:6736 __schedule_loop kernel/sched/core.c:6813 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6828 schedule_timeout+0x1be/0x310 kernel/time/timer.c:2572 rcu_gp_fqs_loop+0x2df/0x1370 kernel/rcu/tree.c:1663 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:1862 kthread+0x2f2/0x390 kernel/kthread.c:388 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 5119 Comm: syz-executor102 Not tainted 6.8.0-syzkaller-08951-gfe46a7dd189e #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024 RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:26 [inline] RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:67 [inline] RIP: 0010:lockdep_hardirqs_on_prepare+0x10c/0x780 kernel/locking/lockdep.c:4340 Code: 40 4c 89 f3 48 c1 eb 03 80 3c 13 00 74 12 4c 89 f7 e8 18 e7 86 00 48 ba 00 00 00 00 00 fc ff df 48 c7 44 24 40 00 00 00 00 9c <8f> 44 24 40 80 3c 13 00 74 12 4c 89 f7 e8 02 e6 86 00 48 ba 00 00 RSP: 0018:ffffc900046efaf8 EFLAGS: 00000046 RAX: 0000000000000004 RBX: 1ffff920008ddf68 RCX: ffffffff944dd603 RDX: dffffc0000000000 RSI: ffffffff8bfed2e0 RDI: ffffffff8bfed2a0 RBP: ffffc900046efba8 R08: ffffffff8f873a6f R09: 1ffffffff1f0e74d R10: dffffc0000000000 R11: fffffbfff1f0e74e R12: 0000000000000000 R13: 0000000000000000 R14: ffffc900046efb40 R15: 1ffff920008ddf64 FS: 00005555686df3c0(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000002006b000 CR3: 0000000022820000 CR4: 0000000000350ef0 Call Trace: trace_hardirqs_on+0x28/0x40 kernel/trace/trace_preemptirq.c:61 irqentry_exit+0x63/0x90 kernel/entry/common.c:351 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline] RIP: 0010:_raw_spin_unlock_irq+0x29/0x50 kernel/locking/spinlock.c:202 Code: 90 f3 0f 1e fa 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 0a b4 f2 f5 48 89 df e8 c2 f3 f3 f5 e8 1d 19 1d f6 fb bf 01 00 00 00 52 e0 e5 f5 65 8b 05 a3 c4 84 74 85 c0 74 06 5b e9 71 40 00 00 RSP: 0018:ffffc900046efc70 EFLAGS: 00000282 RAX: 564bc3e9597d6800 RBX: ffff8880267bae40 RCX: ffffffff944dd603 RDX: dffffc0000000000 RSI: ffffffff8baac1e0 RDI: 0000000000000001 RBP: ffffc900046efdb0 R08: ffffffff8f873a6f R09: 1ffffffff1f0e74d R10: dffffc0000000000 R11: fffffbfff1f0e74e R12: 1ffff11004cf765b R13: 000000001c000004 R14: 0000000000000021 R15: ffff8880267bb2d8 spin_unlock_irq include/linux/spinlock.h:401 [inline] get_signal+0x156e/0x1850 kernel/signal.c:2910 arch_do_signal_or_restart+0x96/0x860 arch/x86/kernel/signal.c:310 exit_to_user_mode_loop kernel/entry/common.c:105 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:201 [inline] syscall_exit_to_user_mode+0xc9/0x360 kernel/entry/common.c:212 do_syscall_64+0x10a/0x240 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x6d/0x75 RIP: 0033:0x7f075e442e79 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 18 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffe6afff1c8 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000003 RCX: 00007f075e442e79 RDX: 000000002006b000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00000000000f4240 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00005555686df370 R13: 0000000000000003 R14: 00007ffe6afff240 R15: 00007ffe6afff230 INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.514 msecs