rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: (detected by 1, t=10502 jiffies, g=6825, q=6 ncpus=2) rcu: All QSes seen, last rcu_preempt kthread activity 10501 (4294966999-4294956498), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 10502 jiffies! g6825 f0x2 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:25040 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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 5118 Comm: syz-executor383 Not tainted 6.8.0-syzkaller-08951-gfe46a7dd189e #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024 RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x70 kernel/kcov.c:200 Code: 89 fb e8 23 00 00 00 48 8b 3d 6c 1c 1c 0c 48 89 de 5b e9 23 fb 57 00 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 48 8b 04 24 65 48 8b 0c 25 80 d0 03 00 65 8b 15 20 db RSP: 0018:ffffc90000007eb0 EFLAGS: 00000093 RAX: 0000000080010002 RBX: 7fffffffffffffff RCX: ffff888075350000 RDX: ffff8880b942c90c RSI: 7fffffffffffffff RDI: 0000004587792f90 RBP: ffff8880b942c930 R08: ffffffff818276aa R09: 1ffffffff1f0e74d R10: dffffc0000000000 R11: ffffffff81353f80 R12: 0000000000000011 R13: ffff8880b942cca8 R14: dffffc0000000000 R15: 0000004587792f90 FS: 000055555ee9d3c0(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f77ebb89d08 CR3: 00000000230a0000 CR4: 0000000000350ef0 Call Trace: hrtimer_interrupt+0x324/0x990 kernel/time/hrtimer.c:1812 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1032 [inline] __sysvec_apic_timer_interrupt+0x109/0x3a0 arch/x86/kernel/apic/apic.c:1049 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1043 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:ffffc90004617c70 EFLAGS: 00000282 RAX: 37fcdcdfb40d1800 RBX: ffff88802abad340 RCX: ffffffff944dd603 RDX: dffffc0000000000 RSI: ffffffff8baac1e0 RDI: 0000000000000001 RBP: ffffc90004617db0 R08: ffffffff8f873a6f R09: 1ffffffff1f0e74d R10: dffffc0000000000 R11: fffffbfff1f0e74e R12: 1ffff11005575afb R13: 000000001c000004 R14: 0000000000000021 R15: ffff88802abad7d8 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: 0033:0x7f77ebad18d0 Code: 41 54 55 48 89 f5 53 89 fb 48 83 ec 18 48 83 3d 1d 57 0b 00 00 89 54 24 0c 74 08 84 c9 0f 85 09 02 00 00 31 c0 ba 01 00 00 00 0f b1 15 30 84 0b 00 0f 85 0f 02 00 00 4c 8d 25 23 84 0b 00 4c RSP: 002b:00007fff58e62210 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000001 RDX: 0000000000000001 RSI: 00007f77ebb87130 RDI: 0000000000000000 RBP: 00007f77ebb87130 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000293 R12: 000055555ee9d370 R13: 0000000000000001 R14: 00007fff58e622e0 R15: 00007fff58e622d0 INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.675 msecs