rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=1224/1/0x4000000000000000 softirq=54813/54814 fqs=0 rcu: (detected by 0, t=10505 jiffies, g=76785, q=173 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 16341 Comm: syz-executor.2 Not tainted 6.6.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/04/2023 RIP: 0010:advance_sched+0xac8/0xc80 net/sched/sch_taprio.c:998 Code: ff e8 5c 77 e1 01 89 c3 31 ff 89 c6 e8 41 83 a5 f8 85 db 74 10 e8 98 04 8e f8 84 c0 74 0e e8 7f 7f a5 f8 eb 56 e8 78 7f a5 f8 4f e8 31 77 e1 01 89 c3 31 ff 89 c6 e8 16 83 a5 f8 85 db 74 10 RSP: 0018:ffffc900001f0c90 EFLAGS: 00000046 RAX: ffffffff88e82418 RBX: 0000000000000000 RCX: ffff88808461d940 RDX: 0000000080010001 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 1783b99061cd0000 R08: ffffffff88e823ff R09: 1ffff11006ba602b R10: dffffc0000000000 R11: ffffed1006ba602c R12: dffffc0000000000 R13: 1783b99061cc0000 R14: ffff88802a00fc00 R15: ffff888035d30360 FS: 00007fcab01266c0(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020143000 CR3: 0000000038391000 CR4: 00000000003526e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __run_hrtimer kernel/time/hrtimer.c:1688 [inline] __hrtimer_run_queues+0x59f/0xd10 kernel/time/hrtimer.c:1752 hrtimer_interrupt+0x396/0x980 kernel/time/hrtimer.c:1814 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1063 [inline] __sysvec_apic_timer_interrupt+0x104/0x390 arch/x86/kernel/apic/apic.c:1080 sysvec_apic_timer_interrupt+0x90/0xb0 arch/x86/kernel/apic/apic.c:1074 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:645 RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0xd8/0x140 kernel/locking/spinlock.c:194 Code: 9c 8f 44 24 20 42 80 3c 23 00 74 08 4c 89 f7 e8 5e cb 13 f7 f6 44 24 21 02 75 4e 41 f7 c7 00 02 00 00 74 01 fb bf 01 00 00 00 83 92 8c f6 65 8b 05 04 f6 2f 75 85 c0 74 3f 48 c7 04 24 0e 36 RSP: 0018:ffffc90004b7f580 EFLAGS: 00000206 RAX: 2b3a749554e50a00 RBX: 1ffff9200096feb4 RCX: ffffffff81946c0c RDX: dffffc0000000000 RSI: ffffffff8b599400 RDI: 0000000000000001 RBP: ffffc90004b7f610 R08: ffffffff8e9a662f R09: 1ffffffff1d34cc5 R10: dffffc0000000000 R11: fffffbfff1d34cc6 R12: dffffc0000000000 R13: 1ffff9200096feb0 R14: ffffc90004b7f5a0 R15: 0000000000000246 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] __wake_up_common_lock kernel/sched/wait.c:140 [inline] __wake_up_sync_key+0x125/0x1c0 kernel/sched/wait.c:213 __unix_dgram_recvmsg+0x602/0x1260 net/unix/af_unix.c:2389 sock_recvmsg_nosec+0x86/0xd0 net/socket.c:1027 ____sys_recvmsg+0x483/0x580 net/socket.c:2758 ___sys_recvmsg net/socket.c:2802 [inline] do_recvmmsg+0x474/0xae0 net/socket.c:2896 __sys_recvmmsg net/socket.c:2975 [inline] __do_sys_recvmmsg net/socket.c:2998 [inline] __se_sys_recvmmsg net/socket.c:2991 [inline] __x64_sys_recvmmsg+0x199/0x240 net/socket.c:2991 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7fcaaf47cae9 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:00007fcab01260c8 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007fcaaf59c050 RCX: 00007fcaaf47cae9 RDX: 0000000000010106 RSI: 00000000200000c0 RDI: 0000000000000004 RBP: 00007fcaaf4c847a R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000006e R14: 00007fcaaf59c050 R15: 00007ffd61565018 rcu: rcu_preempt kthread starved for 10505 jiffies! g76785 f0x0 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:26856 pid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x1873/0x48f0 kernel/sched/core.c:6695 schedule+0xc3/0x180 kernel/sched/core.c:6771 schedule_timeout+0x1bd/0x310 kernel/time/timer.c:2167 rcu_gp_fqs_loop+0x2c6/0x1010 kernel/rcu/tree.c:1613 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:1812 kthread+0x2b8/0x350 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 PID: 11913 Comm: kworker/u4:7 Not tainted 6.6.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/04/2023 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:csd_lock_wait kernel/smp.c:300 [inline] RIP: 0010:smp_call_function_many_cond+0x1805/0x2890 kernel/smp.c:844 Code: 45 8b 65 00 44 89 e6 83 e6 01 31 ff e8 c4 43 0b 00 41 83 e4 01 49 bc 00 00 00 00 00 fc ff df 75 07 e8 ff 3f 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 e3 3f RSP: 0018:ffffc9000c71f780 EFLAGS: 00000293 RAX: ffffffff818263ad RBX: 1ffff110173282cd RCX: ffff888029e49dc0 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc9000c71f980 R08: ffffffff8182637c R09: 1ffffffff1d34cc5 R10: dffffc0000000000 R11: fffffbfff1d34cc6 R12: dffffc0000000000 R13: ffff8880b9941668 R14: ffff8880b983d440 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f2e6cf75198 CR3: 000000000d130000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1012 on_each_cpu include/linux/smp.h:71 [inline] text_poke_sync arch/x86/kernel/alternative.c:1998 [inline] text_poke_bp_batch+0x350/0xb20 arch/x86/kernel/alternative.c:2208 text_poke_flush arch/x86/kernel/alternative.c:2399 [inline] text_poke_finish+0x30/0x50 arch/x86/kernel/alternative.c:2406 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 static_key_enable_cpuslocked+0x132/0x250 kernel/jump_label.c:205 static_key_enable+0x1a/0x20 kernel/jump_label.c:218 toggle_allocation_gate+0xb5/0x250 mm/kfence/core.c:830 process_one_work+0x781/0x1130 kernel/workqueue.c:2630 process_scheduled_works kernel/workqueue.c:2703 [inline] worker_thread+0xabf/0x1060 kernel/workqueue.c:2784 kthread+0x2b8/0x350 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304