rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=20d/1/0x4000000000000000 softirq=121628/121629 fqs=3 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P9222/1:b..l (detected by 1, t=10502 jiffies, g=189885, q=247) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 6206 Comm: syz-executor.4 Not tainted 5.16.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:skip_atoi+0x92/0xe0 lib/vsprintf.c:162 Code: 84 c0 75 4b 0f be 43 ff 48 89 da 83 e2 07 44 8d 74 05 d0 48 89 d8 48 c1 e8 03 42 0f b6 04 20 38 d0 7f 04 84 c0 75 2f 0f be 2b 09 00 00 00 83 ed 30 89 ee e8 3f 81 76 fd 83 fd 09 76 96 e8 15 RSP: 0018:ffffc9000404f458 EFLAGS: 00000002 RAX: 0000000000000005 RBX: ffffffff89accdc9 RCX: 0000000000000000 RDX: 0000000000000001 RSI: ffffffff8400f771 RDI: ffffffff89accdc8 RBP: 000000000000006c R08: 0000000000000009 R09: ffffffff840118aa R10: ffffffff84011d01 R11: 0000000000000036 R12: dffffc0000000000 R13: ffffc9000404f4c0 R14: 0000000000000006 R15: 0000000000000036 FS: 0000000000000000(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb8fe22e090 CR3: 0000000072bd6000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: format_decode+0x882/0xad0 lib/vsprintf.c:2573 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: 0033:0x7f68e98cffe9 Code: Unable to access opcode bytes at RIP 0x7f68e98cffbf. RSP: 002b:00007fff33a77388 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00007fff33a77530 RCX: 00007f68e98cffe9 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000043 RBP: 0000000000000000 R08: 0000000000000025 R09: 00007fff33a77530 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f68e992a05e R13: 000000000000001c R14: 0000000000000013 R15: 00007fff33a77570 task:syz-executor.1 state:R running task stack:27400 pid: 9222 ppid: 3641 flags:0x00000000 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:check_kcov_mode kernel/kcov.c:166 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0xd/0x60 kernel/kcov.c:200 Code: 00 00 e9 46 31 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 09 f9 8a 7e 89 c1 48 8b 34 24 <81> e1 00 01 00 00 65 48 8b 14 25 40 70 02 00 a9 00 01 ff 00 74 0e RSP: 0018:ffffc9000ccbf5b0 EFLAGS: 00000202 RAX: 0000000080000000 RBX: 0000000000000000 RCX: 0000000080000000 RDX: 0000000000000000 RSI: ffffffff820abdf0 RDI: 0000000000000003 RBP: ffff88807f0e0000 R08: 0000000000000000 R09: 0000000000000001 R10: ffffffff820abde2 R11: 0000000000000000 R12: ffff888145bb12b8 R13: 0000000000000000 R14: ffff88807f0e0678 R15: 0000000000000001 rcu_read_unlock include/linux/rcupdate.h:720 [inline] ext4_get_group_desc+0x1f0/0x500 fs/ext4/balloc.c:284 __ext4_get_inode_loc+0x1c9/0x12e0 fs/ext4/inode.c:4403 ext4_get_inode_loc fs/ext4/inode.c:4544 [inline] ext4_reserve_inode_write+0x159/0x3c0 fs/ext4/inode.c:5713 __ext4_mark_inode_dirty+0x17b/0x8d0 fs/ext4/inode.c:5882 ext4_dirty_inode+0xd4/0x110 fs/ext4/inode.c:5919 __mark_inode_dirty+0x45b/0xfe0 fs/fs-writeback.c:2399 mark_inode_dirty include/linux/fs.h:2451 [inline] generic_write_end+0x31b/0x500 fs/buffer.c:2202 ext4_da_write_end+0x1c2/0x990 fs/ext4/inode.c:3059 generic_perform_write+0x2c6/0x510 mm/filemap.c:3765 ext4_buffered_write_iter+0x1ac/0x3b0 fs/ext4/file.c:269 ext4_file_write_iter+0x423/0x14e0 fs/ext4/file.c:681 call_write_iter include/linux/fs.h:2162 [inline] new_sync_write+0x429/0x660 fs/read_write.c:503 vfs_write+0x7cd/0xae0 fs/read_write.c:590 ksys_write+0x12d/0x250 fs/read_write.c:643 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: 0033:0x7fb8fe119fe9 RSP: 002b:00007fb8fca8f168 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fb8fe22cf60 RCX: 00007fb8fe119fe9 RDX: 000000000208e19b RSI: 0000000020000200 RDI: 0000000000000003 RBP: 00007fb8fe17408d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fffc122b17f R14: 00007fb8fca8f300 R15: 0000000000022000 rcu: rcu_preempt kthread starved for 10496 jiffies! g189885 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:28736 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 1 CPU: 1 PID: 5887 Comm: kworker/u4:8 Not tainted 5.16.0-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:csd_lock_wait kernel/smp.c:440 [inline] RIP: 0010:smp_call_function_many_cond+0x45c/0xc20 kernel/smp.c:969 Code: 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 90 7a 0b 00 f3 90 41 0f b6 04 24 40 38 c5 7c 08 <84> c0 0f 85 33 06 00 00 8b 43 08 31 ff 83 e0 01 41 89 c7 89 c6 e8 RSP: 0018:ffffc9000406f9f8 EFLAGS: 00000206 RAX: 0000000000000000 RBX: ffff8880b9c41d60 RCX: 0000000000000000 RDX: ffff88807aa80000 RSI: ffffffff816bfc60 RDI: 0000000000000003 RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000001 R10: ffffffff816bfc86 R11: 0000000000000000 R12: ffffed10173883ad R13: 0000000000000000 R14: ffff8880b9c41d68 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+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:734 [inline] toggle_allocation_gate+0x100/0x390 mm/kfence/core.c:726 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: 84 c0 test %al,%al 2: 75 4b jne 0x4f 4: 0f be 43 ff movsbl -0x1(%rbx),%eax 8: 48 89 da mov %rbx,%rdx b: 83 e2 07 and $0x7,%edx e: 44 8d 74 05 d0 lea -0x30(%rbp,%rax,1),%r14d 13: 48 89 d8 mov %rbx,%rax 16: 48 c1 e8 03 shr $0x3,%rax 1a: 42 0f b6 04 20 movzbl (%rax,%r12,1),%eax 1f: 38 d0 cmp %dl,%al 21: 7f 04 jg 0x27 23: 84 c0 test %al,%al 25: 75 2f jne 0x56 27: 0f be 2b movsbl (%rbx),%ebp * 2a: bf 09 00 00 00 mov $0x9,%edi <-- trapping instruction 2f: 83 ed 30 sub $0x30,%ebp 32: 89 ee mov %ebp,%esi 34: e8 3f 81 76 fd callq 0xfd768178 39: 83 fd 09 cmp $0x9,%ebp 3c: 76 96 jbe 0xffffffd4 3e: e8 .byte 0xe8 3f: 15 .byte 0x15