rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=a94c/1/0x4000000000000000 softirq=36967/36968 fqs=5 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P10826/1:b..l rcu: (detected by 1, t=10502 jiffies, g=28361, q=530 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 10832 Comm: syz.4.2230 Not tainted 6.15.0-rc1-syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:_raw_spin_lock+0x0/0x40 kernel/locking/spinlock.c:153 Code: c0 48 89 ea 48 89 df 31 f6 5b 5d e9 0a d6 d0 f9 cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 53 48 89 fb bf 01 00 00 00 e8 9e 67 14 f6 ff 74 24 08 RSP: 0018:ffffc90000007d88 EFLAGS: 00000046 RAX: ffff888033b2f2e8 RBX: ffff888033b2f340 RCX: 1ffff1100febca6b RDX: 0000000000000000 RSI: ffffffff89825b1a RDI: ffff888033b2f2e8 RBP: ffff88807cbfc000 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880b8427840 R13: 0000000000000000 R14: ffff888033b2f340 R15: ffffffff89825b00 FS: 00007fe8fddf66c0(0000) GS:ffff8881249b3000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2ff1cff8 CR3: 000000002a50c000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: spin_lock include/linux/spinlock.h:351 [inline] advance_sched+0xd9/0xc80 net/sched/sch_taprio.c:924 __run_hrtimer kernel/time/hrtimer.c:1761 [inline] __hrtimer_run_queues+0x1ff/0xad0 kernel/time/hrtimer.c:1825 hrtimer_interrupt+0x397/0x8e0 kernel/time/hrtimer.c:1887 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline] __sysvec_apic_timer_interrupt+0x108/0x3f0 arch/x86/kernel/apic/apic.c:1055 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1049 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 8b 74 24 08 48 89 fb 48 83 c7 18 e8 fa 4b 23 f6 48 89 df e8 a2 9f 23 f6 e8 5d 36 4e f6 fb bf 01 00 00 00 c2 0d 14 f6 65 8b 05 6b 04 32 08 85 c0 74 06 5b c3 cc cc cc cc RSP: 0018:ffffc9000317fa70 EFLAGS: 00000202 RAX: 00000000000000bf RBX: ffff88802bcc5c80 RCX: ffffffff81c3010f RDX: 0000000000000000 RSI: ffffffff8dbeeb26 RDI: 0000000000000001 RBP: 1ffff9200062ff54 R08: 0000000000000001 R09: 0000000000000001 R10: ffffffff90865317 R11: 0000000000000000 R12: 0000000000000000 R13: dffffc0000000000 R14: ffff88802bcc5c80 R15: 0000000000000000 spin_unlock_irq include/linux/spinlock.h:401 [inline] acct_collect+0x500/0x8f0 kernel/acct.c:623 do_exit+0xf59/0x2c30 kernel/exit.c:932 do_group_exit+0xd3/0x2a0 kernel/exit.c:1102 get_signal+0x2673/0x26d0 kernel/signal.c:3034 arch_do_signal_or_restart+0x8f/0x7d0 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop kernel/entry/common.c:111 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x150/0x2a0 kernel/entry/common.c:218 do_syscall_64+0xda/0x260 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe8fff8d169 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:00007fe8fddf60e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007fe9001a5fa8 RCX: 00007fe8fff8d169 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fe9001a5fa8 RBP: 00007fe9001a5fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fe9001a5fac R13: 0000000000000000 R14: 00007ffff004bdb0 R15: 00007ffff004be98 task:syz.2.2227 state:R running task stack:26696 pid:10826 tgid:10825 ppid:5824 task_flags:0x400140 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x116f/0x5de0 kernel/sched/core.c:6767 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7090 irqentry_exit+0x36/0x90 kernel/entry/common.c:354 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:__local_bh_enable_ip+0xac/0x120 kernel/softirq.c:414 Code: 1d 49 f8 29 12 65 8b 05 42 f8 29 12 a9 00 ff ff 00 74 4d bf 01 00 00 00 e8 81 01 0c 00 e8 0c 2a 46 00 fb 65 8b 05 24 f8 29 12 <85> c0 74 52 5b 5d c3 cc cc cc cc 65 8b 05 2e 32 2a 12 85 c0 75 9e RSP: 0018:ffffc900036ef958 EFLAGS: 00000202 RAX: 0000000080000000 RBX: 00000000fffffe01 RCX: ffffffff81c3010f RDX: 0000000000000000 RSI: ffffffff8dbeeb26 RDI: ffffffff8bf46500 RBP: ffffffff898aa732 R08: 0000000000000001 R09: 0000000000000001 R10: ffffffff90865317 R11: 0000000000000000 R12: ffffc90003dad000 R13: ffffc900036efab0 R14: ffff88807f5e0000 R15: ffffe8ffffd22190 local_bh_enable include/linux/bottom_half.h:33 [inline] bpf_test_run+0x397/0xa70 net/bpf/test_run.c:437 bpf_prog_test_run_skb+0xb92/0x2280 net/bpf/test_run.c:1093 bpf_prog_test_run kernel/bpf/syscall.c:4427 [inline] __sys_bpf+0x1485/0x4d80 kernel/bpf/syscall.c:5852 __do_sys_bpf kernel/bpf/syscall.c:5941 [inline] __se_sys_bpf kernel/bpf/syscall.c:5939 [inline] __x64_sys_bpf+0x78/0xc0 kernel/bpf/syscall.c:5939 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fd61138d169 RSP: 002b:00007fd60f1f6038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007fd6115a5fa0 RCX: 00007fd61138d169 RDX: 0000000000000050 RSI: 0000200000000d80 RDI: 000000000000000a RBP: 00007fd61140e2a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fd6115a5fa0 R15: 00007fffc4e8f5a8 rcu: rcu_preempt kthread starved for 10492 jiffies! g28361 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:27304 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x116f/0x5de0 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6860 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2046 rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2248 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 UID: 0 PID: 73 Comm: kworker/u8:4 Not tainted 6.15.0-rc1-syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline] RIP: 0010:write_comp_data+0x18/0x90 kernel/kcov.c:246 Code: 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 49 89 d2 49 89 f8 49 89 f1 65 48 8b 15 c7 98 eb 11 65 8b 05 d8 98 eb 11 00 01 ff 00 74 1d f6 c4 01 74 67 a9 00 00 0f 00 75 60 a9 00 00 RSP: 0018:ffffc90001577930 EFLAGS: 00000202 RAX: 0000000000000001 RBX: ffff8880b8441720 RCX: ffffffff81af26b9 RDX: ffff88801cfa2440 RSI: 0000000000000000 RDI: 0000000000000005 RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: ffffed10170882e5 R13: 0000000000000001 R14: dffffc0000000000 R15: ffff8880b853b040 FS: 0000000000000000(0000) GS:ffff888124ab3000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fe9001a7bac CR3: 000000000e182000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: csd_lock_wait kernel/smp.c:340 [inline] smp_call_function_many_cond+0x4c9/0x1290 kernel/smp.c:885 on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1052 on_each_cpu include/linux/smp.h:71 [inline] text_poke_sync arch/x86/kernel/alternative.c:2455 [inline] text_poke_bp_batch+0x220/0x760 arch/x86/kernel/alternative.c:2665 text_poke_flush arch/x86/kernel/alternative.c:2856 [inline] text_poke_flush arch/x86/kernel/alternative.c:2853 [inline] text_poke_finish+0x30/0x40 arch/x86/kernel/alternative.c:2863 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 jump_label_update+0x376/0x550 kernel/jump_label.c:919 static_key_enable_cpuslocked+0x1b7/0x270 kernel/jump_label.c:210 static_key_enable+0x1a/0x20 kernel/jump_label.c:223 toggle_allocation_gate mm/kfence/core.c:850 [inline] toggle_allocation_gate+0xfa/0x280 mm/kfence/core.c:842 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3238 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245