rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (0 ticks this GP) idle=8b9/1/0x4000000000000000 softirq=100742/100744 fqs=2 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P2962/1:b..l (detected by 0, t=10502 jiffies, g=148549, q=810) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 1032 Comm: kworker/u4:5 Not tainted 5.17.0-rc2-syzkaller-00039-g9f7fb8de5d9b #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: bat_events batadv_nc_worker RIP: 0010:lockdep_recursion_finish kernel/locking/lockdep.c:438 [inline] RIP: 0010:lock_acquire kernel/locking/lockdep.c:5641 [inline] RIP: 0010:lock_acquire+0x1c8/0x510 kernel/locking/lockdep.c:5604 Code: 41 0f 94 c1 45 0f b6 c9 e8 05 97 ff ff 48 c7 c7 20 61 ac 89 48 83 c4 20 e8 65 cc ec 07 b8 ff ff ff ff 65 0f c1 05 98 1d a5 7e <83> f8 01 0f 85 b4 02 00 00 9c 58 f6 c4 02 0f 85 9f 02 00 00 48 83 RSP: 0018:ffffc90000dc0c50 EFLAGS: 00000057 RAX: 0000000000000001 RBX: 1ffff920001b818c RCX: 0000000000009748 RDX: 1ffff110037e04eb RSI: 0000000000010003 RDI: 0000000000000000 RBP: 0000000000000001 R08: 0000000000000000 R09: ffffffff8ffbd947 R10: fffffbfff1ff7b28 R11: 0000000000000001 R12: 0000000000000000 R13: 0000000000000000 R14: ffffffff906a6658 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f4356d8d028 CR3: 0000000055563000 CR4: 0000000000350ee0 Call Trace: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x39/0x50 kernel/locking/spinlock.c:162 debug_object_deactivate lib/debugobjects.c:735 [inline] debug_object_deactivate+0x101/0x300 lib/debugobjects.c:723 debug_hrtimer_deactivate kernel/time/hrtimer.c:425 [inline] debug_deactivate kernel/time/hrtimer.c:481 [inline] __run_hrtimer kernel/time/hrtimer.c:1653 [inline] __hrtimer_run_queues+0x3f8/0xe50 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x31c/0x790 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline] __sysvec_apic_timer_interrupt+0x146/0x530 arch/x86/kernel/apic/apic.c:1103 sysvec_apic_timer_interrupt+0x8e/0xc0 arch/x86/kernel/apic/apic.c:1097 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:lock_is_held_type+0xff/0x140 kernel/locking/lockdep.c:5687 Code: 00 00 b8 ff ff ff ff 65 0f c1 05 bc 5e b8 76 83 f8 01 75 29 9c 58 f6 c4 02 75 3d 48 f7 04 24 00 02 00 00 74 01 fb 48 83 c4 08 <44> 89 e8 5b 5d 41 5c 41 5d 41 5e 41 5f c3 45 31 ed eb b9 0f 0b 48 RSP: 0018:ffffc90004cefb60 EFLAGS: 00000296 RAX: 0000000000000046 RBX: 0000000000000002 RCX: 0000000000000001 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffffff8bb83b60 R08: 0000000000000000 R09: ffffffff8d93bc57 R10: fffffbfff1b2778a R11: 0000000000000000 R12: ffff88801bf01d00 R13: 0000000000000000 R14: 00000000ffffffff R15: ffff88801bf02788 lock_is_held include/linux/lockdep.h:283 [inline] rcu_read_lock_sched_held+0x3a/0x70 kernel/rcu/update.c:125 trace_lock_acquire include/trace/events/lock.h:13 [inline] lock_acquire+0x442/0x510 kernel/locking/lockdep.c:5610 rcu_lock_acquire include/linux/rcupdate.h:268 [inline] rcu_read_lock include/linux/rcupdate.h:694 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:408 [inline] batadv_nc_worker+0x12d/0xfa0 net/batman-adv/network-coding.c:719 process_one_work+0x9ac/0x1650 kernel/workqueue.c:2307 worker_thread+0x657/0x1110 kernel/workqueue.c:2454 kthread+0x2e9/0x3a0 kernel/kthread.c:377 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 task:udevd state:R running task stack:25120 pid: 2962 ppid: 1 flags:0x00000000 Call Trace: context_switch kernel/sched/core.c:4986 [inline] __schedule+0xab2/0x4db0 kernel/sched/core.c:6295 preempt_schedule_common+0x45/0xc0 kernel/sched/core.c:6461 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:35 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] _raw_spin_unlock_irqrestore+0x57/0x70 kernel/locking/spinlock.c:194 spin_unlock_irqrestore include/linux/spinlock.h:404 [inline] __wake_up_common_lock+0xde/0x130 kernel/sched/wait.c:140 sock_def_readable+0xec/0x4e0 net/core/sock.c:3147 __netlink_sendskb net/netlink/af_netlink.c:1264 [inline] netlink_sendskb net/netlink/af_netlink.c:1270 [inline] netlink_unicast+0x6d9/0x7e0 net/netlink/af_netlink.c:1358 netlink_sendmsg+0x904/0xe00 net/netlink/af_netlink.c:1919 sock_sendmsg_nosec net/socket.c:705 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:725 ____sys_sendmsg+0x6e8/0x810 net/socket.c:2413 ___sys_sendmsg+0xf3/0x170 net/socket.c:2467 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2496 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7fa0ca7c6163 RSP: 002b:00007fff9f04d0c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007fa0cb715d60 RCX: 00007fa0ca7c6163 RDX: 0000000000000000 RSI: 00007fff9f04d0d8 RDI: 0000000000000004 RBP: 00007fa0cb71fa20 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000020 R11: 0000000000000246 R12: 0000000000000000 R13: 00000000000000b3 R14: 0000000000000000 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 10498 jiffies! g148549 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:28736 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4986 [inline] __schedule+0xab2/0x4db0 kernel/sched/core.c:6295 schedule+0xd2/0x260 kernel/sched/core.c:6368 schedule_timeout+0x14a/0x2a0 kernel/time/timer.c:1881 rcu_gp_fqs_loop+0x186/0x810 kernel/rcu/tree.c:1963 rcu_gp_kthread+0x1de/0x320 kernel/rcu/tree.c:2136 kthread+0x2e9/0x3a0 kernel/kthread.c:377 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 rcu: Stack dump where RCU GP kthread last ran: NMI backtrace for cpu 0 CPU: 0 PID: 4010 Comm: kworker/u4:12 Not tainted 5.17.0-rc2-syzkaller-00039-g9f7fb8de5d9b #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events_unbound toggle_allocation_gate Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_check_gp_kthread_starvation.cold+0x1fb/0x200 kernel/rcu/tree_stall.h:458 print_other_cpu_stall kernel/rcu/tree_stall.h:563 [inline] check_cpu_stall kernel/rcu/tree_stall.h:706 [inline] rcu_pending kernel/rcu/tree.c:3919 [inline] rcu_sched_clock_irq+0x1f7c/0x2150 kernel/rcu/tree.c:2617 update_process_times+0x16d/0x200 kernel/time/timer.c:1785 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:226 tick_sched_timer+0x1b0/0x2d0 kernel/time/tick-sched.c:1428 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x1c0/0xe50 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x31c/0x790 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline] __sysvec_apic_timer_interrupt+0x146/0x530 arch/x86/kernel/apic/apic.c:1103 sysvec_apic_timer_interrupt+0x8e/0xc0 arch/x86/kernel/apic/apic.c:1097 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:csd_lock_wait kernel/smp.c:440 [inline] RIP: 0010:smp_call_function_many_cond+0x447/0xc90 kernel/smp.c:969 Code: 0b 00 85 ed 74 4d 48 b8 00 00 00 00 00 fc ff df 4d 89 f4 4c 89 f5 49 c1 ec 03 83 e5 07 49 01 c4 83 c5 03 e8 2b 7d 0b 00 f3 90 <41> 0f b6 04 24 40 38 c5 7c 08 84 c0 0f 85 95 06 00 00 8b 43 08 31 RSP: 0018:ffffc90005c97a08 EFLAGS: 00000293 RAX: 0000000000000000 RBX: ffff8880b9d3fec0 RCX: 0000000000000000 RDX: ffff8880192ed700 RSI: ffffffff816cf155 RDI: 0000000000000003 RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000001 R10: ffffffff816cf17b R11: 0000000000000000 R12: ffffed10173a7fd9 R13: 0000000000000001 R14: ffff8880b9d3fec8 R15: 0000000000000001 on_each_cpu_cond_mask+0x56/0xa0 kernel/smp.c:1135 on_each_cpu include/linux/smp.h:71 [inline] text_poke_sync arch/x86/kernel/alternative.c:1112 [inline] text_poke_bp_batch+0x1b1/0x510 arch/x86/kernel/alternative.c:1300 text_poke_flush arch/x86/kernel/alternative.c:1470 [inline] text_poke_flush arch/x86/kernel/alternative.c:1467 [inline] text_poke_finish+0x16/0x30 arch/x86/kernel/alternative.c:1477 arch_jump_label_transform_apply+0x13/0x20 arch/x86/kernel/jump_label.c:146 jump_label_update+0x1da/0x400 kernel/jump_label.c:830 static_key_enable_cpuslocked+0x1b1/0x260 kernel/jump_label.c:177 static_key_enable+0x16/0x20 kernel/jump_label.c:190 toggle_allocation_gate mm/kfence/core.c:734 [inline] toggle_allocation_gate+0x100/0x390 mm/kfence/core.c:726 process_one_work+0x9ac/0x1650 kernel/workqueue.c:2307 worker_thread+0x657/0x1110 kernel/workqueue.c:2454 kthread+0x2e9/0x3a0 kernel/kthread.c:377 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 ---------------- Code disassembly (best guess): 0: 41 0f 94 c1 sete %r9b 4: 45 0f b6 c9 movzbl %r9b,%r9d 8: e8 05 97 ff ff callq 0xffff9712 d: 48 c7 c7 20 61 ac 89 mov $0xffffffff89ac6120,%rdi 14: 48 83 c4 20 add $0x20,%rsp 18: e8 65 cc ec 07 callq 0x7eccc82 1d: b8 ff ff ff ff mov $0xffffffff,%eax 22: 65 0f c1 05 98 1d a5 xadd %eax,%gs:0x7ea51d98(%rip) # 0x7ea51dc2 29: 7e * 2a: 83 f8 01 cmp $0x1,%eax <-- trapping instruction 2d: 0f 85 b4 02 00 00 jne 0x2e7 33: 9c pushfq 34: 58 pop %rax 35: f6 c4 02 test $0x2,%ah 38: 0f 85 9f 02 00 00 jne 0x2dd 3e: 48 rex.W 3f: 83 .byte 0x83