rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=6f7/1/0x4000000000000000 softirq=199442/199443 fqs=0 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P8878/1:b..l (detected by 0, t=10502 jiffies, g=338649, q=28) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 3634 Comm: syz-executor.5 Not tainted 5.16.0-rc8-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:27 [inline] RIP: 0010:check_kcov_mode kernel/kcov.c:166 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x60 kernel/kcov.c:200 Code: 48 89 ef 5d e9 41 c7 46 00 5d be 03 00 00 00 e9 a6 37 64 02 66 0f 1f 44 00 00 48 8b be b0 01 00 00 e8 b4 ff ff ff 31 c0 c3 90 <65> 8b 05 49 dd 8a 7e 89 c1 48 8b 34 24 81 e1 00 01 00 00 65 48 8b RSP: 0018:ffffc9000291f480 EFLAGS: 00000083 RAX: 0000000000000000 RBX: 000000000000006c RCX: 0000000000000004 RDX: 0000000000000000 RSI: ffff88801aa6ba00 RDI: 0000000000000003 RBP: ffffc9000291f5a0 R08: 0000000000000009 R09: 0000000000000004 R10: ffffffff84013b91 R11: 0000000000000012 R12: ffffffff89acc9a9 R13: ffffffff89acc9a6 R14: 1ffff92000523e94 R15: 0000000000000036 FS: 0000000000000000(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f412d16d1b8 CR3: 000000004b79c000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: format_decode+0x496/0xad0 lib/vsprintf.c:2599 vsnprintf+0x155/0x14f0 lib/vsprintf.c:2757 sprintf+0xc0/0x100 lib/vsprintf.c:3007 print_time kernel/printk/printk.c:1261 [inline] info_print_prefix+0x248/0x340 kernel/printk/printk.c:1287 record_print_text+0x14d/0x3e0 kernel/printk/printk.c:1336 console_unlock+0x2d8/0xb70 kernel/printk/printk.c:2692 vprintk_emit+0x198/0x4f0 kernel/printk/printk.c:2245 vprintk+0x80/0x90 kernel/printk/printk_safe.c:50 _printk+0xba/0xed kernel/printk/printk.c:2266 stack_trace_print kernel/stacktrace.c:33 [inline] stack_trace_print.cold+0x3b/0x5a kernel/stacktrace.c:24 ref_tracker_dir_exit.cold+0x84/0x1e3 lib/ref_tracker.c:32 __put_net+0x15/0x70 net/core/net_namespace.c:640 put_net include/net/net_namespace.h:268 [inline] put_net_track include/net/net_namespace.h:342 [inline] __sk_destruct+0x6d2/0x920 net/core/sock.c:2042 sk_destruct+0xbd/0xe0 net/core/sock.c:2058 __sk_free+0xef/0x3d0 net/core/sock.c:2069 sk_free+0x78/0xa0 net/core/sock.c:2080 sock_put include/net/sock.h:1912 [inline] __tun_detach+0xdb4/0x13e0 drivers/net/tun.c:681 tun_detach drivers/net/tun.c:693 [inline] tun_chr_close+0xc4/0x180 drivers/net/tun.c:3405 __fput+0x286/0x9f0 fs/file_table.c:280 task_work_run+0xdd/0x1a0 kernel/task_work.c:164 exit_task_work include/linux/task_work.h:32 [inline] do_exit+0xc14/0x2b40 kernel/exit.c:832 do_group_exit+0x125/0x310 kernel/exit.c:929 __do_sys_exit_group kernel/exit.c:940 [inline] __se_sys_exit_group kernel/exit.c:938 [inline] __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:938 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: 0033:0x7f2eed57ae99 Code: Unable to access opcode bytes at RIP 0x7f2eed57ae6f. RSP: 002b:00007ffde280bce8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00007ffde280be90 RCX: 00007f2eed57ae99 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000043 RBP: 0000000000000000 R08: 0000000000000025 R09: 00007ffde280be90 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f2eed5d4fc2 R13: 000000000000001c R14: 0000000000000002 R15: 00007ffde280bed0 task:kworker/u4:15 state:R running task stack:24376 pid: 8878 ppid: 2 flags:0x00004000 Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet Call Trace: context_switch kernel/sched/core.c:4972 [inline] __schedule+0xa9a/0x4900 kernel/sched/core.c:6253 preempt_schedule_irq+0x4e/0x90 kernel/sched/core.c:6668 irqentry_exit+0x31/0x80 kernel/entry/common.c:425 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:batadv_iv_ogm_schedule_buff+0xc00/0x1430 net/batman-adv/bat_iv_ogm.c:844 Code: 85 26 08 00 00 4d 8b 3f 49 81 ff 20 60 8b 90 0f 84 eb 02 00 00 e8 c0 a6 97 f8 49 8d 7f 70 48 89 f8 48 c1 e8 03 42 80 3c 28 00 <0f> 85 e2 07 00 00 48 8b 44 24 08 49 8b 6f 70 80 38 00 0f 85 da 07 RSP: 0018:ffffc9000adcfb98 EFLAGS: 00000246 RAX: 1ffff1100990b00e RBX: ffff8880200df800 RCX: 0000000000000000 RDX: ffff88804de13a00 RSI: ffffffff88dfebf0 RDI: ffff88804c858070 RBP: 0000000000000000 R08: 0000000000000000 R09: ffff8880200df823 R10: ffffffff88dfeea8 R11: 0000000000000000 R12: 000000000000000a R13: dffffc0000000000 R14: ffff88804be20d78 R15: ffff88804c858000 batadv_iv_ogm_schedule net/batman-adv/bat_iv_ogm.c:869 [inline] batadv_iv_ogm_schedule net/batman-adv/bat_iv_ogm.c:862 [inline] batadv_iv_send_outstanding_bat_ogm_packet+0x740/0x910 net/batman-adv/bat_iv_ogm.c:1713 process_one_work+0x9b2/0x1660 kernel/workqueue.c:2298 worker_thread+0x65d/0x1130 kernel/workqueue.c:2445 kthread+0x405/0x4f0 kernel/kthread.c:327 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 rcu: rcu_preempt kthread starved for 10502 jiffies! g338649 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:28680 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4972 [inline] __schedule+0xa9a/0x4900 kernel/sched/core.c:6253 schedule+0xd2/0x260 kernel/sched/core.c:6326 schedule_timeout+0x14a/0x2a0 kernel/time/timer.c:1881 rcu_gp_fqs_loop+0x186/0x810 kernel/rcu/tree.c:1955 rcu_gp_kthread+0x1de/0x320 kernel/rcu/tree.c:2128 kthread+0x405/0x4f0 kernel/kthread.c:327 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: 4477 Comm: kworker/u4:4 Not tainted 5.16.0-rc8-syzkaller #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:481 print_other_cpu_stall kernel/rcu/tree_stall.h:586 [inline] check_cpu_stall kernel/rcu/tree_stall.h:729 [inline] rcu_pending kernel/rcu/tree.c:3878 [inline] rcu_sched_clock_irq+0x1f7c/0x2150 kernel/rcu/tree.c:2597 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:check_kcov_mode+0x7/0x40 kernel/kcov.c:166 Code: 00 e9 59 fe ff ff 48 8b 7c 24 08 e8 a3 6a 47 00 e9 61 fd ff ff cc cc cc cc cc cc cc cc cc cc cc cc cc cc 65 8b 05 f9 e1 8a 7e <89> c2 81 e2 00 01 00 00 a9 00 01 ff 00 74 10 31 c0 85 d2 74 15 8b RSP: 0000:ffffc9000566f9e8 EFLAGS: 00000202 RAX: 0000000000000001 RBX: ffff8880b9d3fca0 RCX: 0000000000000001 RDX: ffff88801efa5700 RSI: ffff88801efa5700 RDI: 0000000000000003 RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000001 R10: ffffffff816c1e56 R11: 0000000000000000 R12: ffffed10173a7f95 R13: 0000000000000001 R14: ffff8880b9d3fca8 R15: 0000000000000001 write_comp_data kernel/kcov.c:221 [inline] __sanitizer_cov_trace_const_cmp4+0x1c/0x70 kernel/kcov.c:287 csd_lock_wait kernel/smp.c:440 [inline] smp_call_function_many_cond+0x476/0xc20 kernel/smp.c:969 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+0x1b3/0x560 arch/x86/kernel/alternative.c:1297 text_poke_flush arch/x86/kernel/alternative.c:1451 [inline] text_poke_flush arch/x86/kernel/alternative.c:1448 [inline] text_poke_finish+0x16/0x30 arch/x86/kernel/alternative.c:1458 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:733 [inline] toggle_allocation_gate+0x100/0x390 mm/kfence/core.c:725 process_one_work+0x9b2/0x1660 kernel/workqueue.c:2298 worker_thread+0x65d/0x1130 kernel/workqueue.c:2445 kthread+0x405/0x4f0 kernel/kthread.c:327 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 ---------------- Code disassembly (best guess): 0: 48 89 ef mov %rbp,%rdi 3: 5d pop %rbp 4: e9 41 c7 46 00 jmpq 0x46c74a 9: 5d pop %rbp a: be 03 00 00 00 mov $0x3,%esi f: e9 a6 37 64 02 jmpq 0x26437ba 14: 66 0f 1f 44 00 00 nopw 0x0(%rax,%rax,1) 1a: 48 8b be b0 01 00 00 mov 0x1b0(%rsi),%rdi 21: e8 b4 ff ff ff callq 0xffffffda 26: 31 c0 xor %eax,%eax 28: c3 retq 29: 90 nop * 2a: 65 8b 05 49 dd 8a 7e mov %gs:0x7e8add49(%rip),%eax # 0x7e8add7a <-- trapping instruction 31: 89 c1 mov %eax,%ecx 33: 48 8b 34 24 mov (%rsp),%rsi 37: 81 e1 00 01 00 00 and $0x100,%ecx 3d: 65 gs 3e: 48 rex.W 3f: 8b .byte 0x8b