rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=b234/1/0x4000000000000000 softirq=35029/35030 fqs=1 rcu: (detected by 1, t=10505 jiffies, g=55237, q=168 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 13133 Comm: syz-executor.2 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:get_current arch/x86/include/asm/current.h:49 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x8/0x70 kernel/kcov.c:206 Code: 8b 3d 6c cd 1a 0c 48 89 de 5b e9 03 ad 54 00 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 8b 04 24 <65> 48 8b 0c 25 40 d0 03 00 65 8b 15 e0 db 6e 7e f7 c2 00 01 ff 00 RSP: 0018:ffffc90000007d58 EFLAGS: 00000002 RAX: ffffffff81828135 RBX: 0000000000000001 RCX: ffffffff818280f8 RDX: ffff88805edc9e00 RSI: ffffffff8bfdfee0 RDI: ffffffff8bfdfea0 RBP: ffffc90000007ea8 R08: ffffffff8182811e R09: 1ffffffff1f0c1bd R10: dffffc0000000000 R11: fffffbfff1f0c1be R12: 1ffff11017285943 R13: ffffffff8978d100 R14: ffff88807d9eb340 R15: 0000000000000001 FS: 00007f42f0a896c0(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000022000900 CR3: 000000007d5d2000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: trace_hrtimer_expire_entry include/trace/events/timer.h:259 [inline] __run_hrtimer kernel/time/hrtimer.c:1689 [inline] __hrtimer_run_queues+0x505/0xd00 kernel/time/hrtimer.c:1756 hrtimer_interrupt+0x396/0x990 kernel/time/hrtimer.c:1818 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1032 [inline] __sysvec_apic_timer_interrupt+0x107/0x3a0 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 da 67 fb f5 48 89 df e8 92 a7 fc f5 e8 fd cc 25 f6 fb bf 01 00 00 00 22 94 ee f5 65 8b 05 33 79 8d 74 85 c0 74 06 5b c3 cc cc cc cc RSP: 0018:ffffc90003127c70 EFLAGS: 00000282 RAX: ceca3ef1e3bbc300 RBX: ffff888022c48940 RCX: ffffffff944a6603 RDX: dffffc0000000000 RSI: ffffffff8baac1e0 RDI: 0000000000000001 RBP: ffffc90003127db0 R08: ffffffff8f860def R09: 1ffffffff1f0c1bd R10: dffffc0000000000 R11: fffffbfff1f0c1be R12: 1ffff110045891bb R13: 000000001c000004 R14: 0000000000000021 R15: ffff888022c48dd8 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: 0033:0x7f42efc7de69 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 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:00007f42f0a890c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e3 RAX: 0000000000000000 RBX: 00007f42efdabf80 RCX: 00007f42efc7de69 RDX: 0000000000000000 RSI: 0000000020003c80 RDI: 0000000000000000 RBP: 00007f42efcca47a R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007f42efdabf80 R15: 00007fff086da318 rcu: rcu_preempt kthread starved for 10500 jiffies! g55237 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:26864 pid:16 tgid:16 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5409 [inline] __schedule+0x1781/0x49d0 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+0x2f0/0x390 kernel/kthread.c:388 ret_from_fork+0x4b/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: CPU: 1 PID: 2451 Comm: kworker/u8:7 Not tainted 6.8.0-syzkaller-08951-gfe46a7dd189e #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:csd_lock_wait kernel/smp.c:311 [inline] RIP: 0010:smp_call_function_many_cond+0x1850/0x2960 kernel/smp.c:855 Code: 45 8b 65 00 44 89 e6 83 e6 01 31 ff e8 d9 d5 0b 00 41 83 e4 01 49 bc 00 00 00 00 00 fc ff df 75 07 e8 84 d1 0b 00 eb 38 f3 90 <42> 0f b6 04 23 84 c0 75 11 41 f7 45 00 01 00 00 00 74 1e e8 68 d1 RSP: 0018:ffffc900098176e0 EFLAGS: 00000293 RAX: ffffffff818922e8 RBX: 1ffff11017288be5 RCX: ffff888029601e00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc900098178e0 R08: ffffffff818922b7 R09: 1ffffffff2595ca0 R10: dffffc0000000000 R11: fffffbfff2595ca1 R12: dffffc0000000000 R13: ffff8880b9445f28 R14: ffff8880b953f440 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ff67568c070 CR3: 000000000df32000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1023 on_each_cpu include/linux/smp.h:71 [inline] text_poke_sync arch/x86/kernel/alternative.c:2086 [inline] text_poke_bp_batch+0x352/0xb30 arch/x86/kernel/alternative.c:2296 text_poke_flush arch/x86/kernel/alternative.c:2487 [inline] text_poke_finish+0x30/0x50 arch/x86/kernel/alternative.c:2494 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 static_key_enable_cpuslocked+0x136/0x260 kernel/jump_label.c:205 static_key_enable+0x1a/0x20 kernel/jump_label.c:218 toggle_allocation_gate+0xb5/0x250 mm/kfence/core.c:826 process_one_work kernel/workqueue.c:3254 [inline] process_scheduled_works+0xa00/0x1770 kernel/workqueue.c:3335 worker_thread+0x86d/0xd70 kernel/workqueue.c:3416 kthread+0x2f0/0x390 kernel/kthread.c:388 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243