rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=fb3c/1/0x4000000000000000 softirq=33966/33967 fqs=0 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P10941/1:b..l P5060/1:b..l rcu: (detected by 1, t=10506 jiffies, g=47517, q=210 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 6531 Comm: kworker/u4:15 Not tainted 6.4.0-syzkaller-12069-gc17414a273b8 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023 Workqueue: netns cleanup_net RIP: 0010:variable_test_bit arch/x86/include/asm/bitops.h:228 [inline] RIP: 0010:arch_test_bit arch/x86/include/asm/bitops.h:240 [inline] RIP: 0010:_test_bit include/asm-generic/bitops/instrumented-non-atomic.h:142 [inline] RIP: 0010:cpumask_test_cpu include/linux/cpumask.h:504 [inline] RIP: 0010:cpu_online include/linux/cpumask.h:1082 [inline] RIP: 0010:trace_hrtimer_start include/trace/events/timer.h:202 [inline] RIP: 0010:debug_activate kernel/time/hrtimer.c:478 [inline] RIP: 0010:enqueue_hrtimer+0x80/0x310 kernel/time/hrtimer.c:1087 Code: e8 d5 6a 10 00 89 eb 48 89 d8 48 c1 e8 06 48 8d 3c c5 28 4c 98 8e be 08 00 00 00 e8 4a 1e 69 00 31 ed 48 0f a3 1d f8 b4 1c 0d <0f> 92 c3 40 0f 92 c5 bf 02 00 00 00 89 ee e8 2d 6d 10 00 31 ff 89 RSP: 0018:ffffc90000007d28 EFLAGS: 00000047 RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff817b9726 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8e984c28 RBP: 0000000000000000 R08: ffffffff8e984c2f R09: 1ffffffff1d30985 R10: dffffc0000000000 R11: fffffbfff1d30986 R12: dffffc0000000000 R13: ffff8880b982b840 R14: ffff88807f557340 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000056326d544f70 CR3: 0000000037f40000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __run_hrtimer kernel/time/hrtimer.c:1705 [inline] __hrtimer_run_queues+0x6c0/0xd10 kernel/time/hrtimer.c:1752 hrtimer_interrupt+0x396/0x980 kernel/time/hrtimer.c:1814 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1098 [inline] __sysvec_apic_timer_interrupt+0x13f/0x480 arch/x86/kernel/apic/apic.c:1115 sysvec_apic_timer_interrupt+0x90/0xb0 arch/x86/kernel/apic/apic.c:1109 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:645 RIP: 0010:lock_acquire+0x25a/0x520 kernel/locking/lockdep.c:5765 Code: 2b 00 74 08 4c 89 f7 e8 94 58 79 00 f6 44 24 61 02 0f 85 84 01 00 00 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 44 25 00 00 00 00 00 43 c7 44 25 09 00 00 00 00 43 c7 44 25 RSP: 0018:ffffc90003aff8c0 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 1ffff9200075ff24 RCX: ffffffff816b71a7 RDX: 0000000000000000 RSI: ffffffff8b0aa1c0 RDI: ffffffff8b589e20 RBP: ffffc90003affa20 R08: dffffc0000000000 R09: 1ffffffff20f6060 R10: dffffc0000000000 R11: fffffbfff20f6061 R12: 1ffff9200075ff20 R13: dffffc0000000000 R14: ffffc90003aff920 R15: 0000000000000246 rcu_lock_acquire+0x2e/0x40 include/linux/rcupdate.h:303 rcu_read_lock include/linux/rcupdate.h:749 [inline] inet_twsk_purge+0x128/0xad0 net/ipv4/inet_timewait_sock.c:292 ops_exit_list net/core/net_namespace.c:175 [inline] cleanup_net+0x767/0xb80 net/core/net_namespace.c:614 process_one_work+0x92c/0x12c0 kernel/workqueue.c:2597 worker_thread+0xa63/0x1210 kernel/workqueue.c:2748 kthread+0x2b8/0x350 kernel/kthread.c:389 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308 task:syz-executor.5 state:R running task stack:20040 pid:5060 ppid:5041 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x1873/0x48f0 kernel/sched/core.c:6710 preempt_schedule_common+0x83/0xc0 kernel/sched/core.c:6879 preempt_schedule+0xdd/0xf0 kernel/sched/core.c:6903 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45 __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline] _raw_spin_unlock_irq+0x40/0x50 kernel/locking/spinlock.c:202 bdi_split_work_to_wbs+0x54d/0x8c0 fs/fs-writeback.c:977 sync_inodes_sb+0x28a/0xab0 fs/fs-writeback.c:2735 sync_filesystem+0x16f/0x220 fs/sync.c:64 generic_shutdown_super+0x6f/0x340 fs/super.c:472 kill_block_super+0x68/0xa0 fs/super.c:1417 deactivate_locked_super+0xa4/0x110 fs/super.c:330 cleanup_mnt+0x426/0x4c0 fs/namespace.c:1254 task_work_run+0x24a/0x300 kernel/task_work.c:179 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop+0xd9/0x100 kernel/entry/common.c:171 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:204 __syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline] syscall_exit_to_user_mode+0x64/0x280 kernel/entry/common.c:297 do_syscall_64+0x4d/0xc0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f2b91a8d7f7 RSP: 002b:00007ffe908e4928 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007f2b91a8d7f7 RDX: 00007ffe908e49fb RSI: 000000000000000a RDI: 00007ffe908e49f0 RBP: 00007ffe908e49f0 R08: 00000000ffffffff R09: 00007ffe908e47c0 R10: 0000555555fb1893 R11: 0000000000000246 R12: 00007f2b91ad643b R13: 00007ffe908e5ab0 R14: 0000555555fb1810 R15: 00007ffe908e5af0 task:udevd state:R running task stack:24936 pid:10941 ppid:4470 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x1873/0x48f0 kernel/sched/core.c:6710 preempt_schedule_common+0x83/0xc0 kernel/sched/core.c:6879 preempt_schedule+0xdd/0xf0 kernel/sched/core.c:6903 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] _raw_spin_unlock_irqrestore+0x12c/0x140 kernel/locking/spinlock.c:194 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:208 sock_def_readable+0x1c4/0x410 net/core/sock.c:3311 unix_dgram_sendmsg+0x15b3/0x2070 net/unix/af_unix.c:2084 sock_sendmsg_nosec net/socket.c:725 [inline] sock_sendmsg net/socket.c:748 [inline] sock_write_iter+0x39a/0x520 net/socket.c:1129 call_write_iter include/linux/fs.h:1871 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x782/0xaf0 fs/read_write.c:584 ksys_write+0x1a0/0x2c0 fs/read_write.c:637 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: 0033:0x7fa1aad16bf2 RSP: 002b:00007ffe72f3da58 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fa1aad16bf2 RDX: 0000000000000000 RSI: 00007ffe72f3daaf RDI: 000000000000000a RBP: 00007ffe72f3daaf R08: 0000000000000001 R09: 0000000000000000 R10: 000000000000010f R11: 0000000000000246 R12: 000000000000000a R13: 00007fa1ab0afae0 R14: 0000000000000000 R15: 000056326d506910 rcu: rcu_preempt kthread starved for 10506 jiffies! g47517 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:26600 pid:16 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x1873/0x48f0 kernel/sched/core.c:6710 schedule+0xc3/0x180 kernel/sched/core.c:6786 schedule_timeout+0x1bd/0x310 kernel/time/timer.c:2167 rcu_gp_fqs_loop+0x2c6/0x1010 kernel/rcu/tree.c:1609 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:1808 kthread+0x2b8/0x350 kernel/kthread.c:389 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 PID: 6687 Comm: kworker/u4:16 Not tainted 6.4.0-syzkaller-12069-gc17414a273b8 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:csd_lock_wait kernel/smp.c:296 [inline] RIP: 0010:smp_call_function_many_cond+0x1856/0x27d0 kernel/smp.c:835 Code: 03 84 c0 75 7e 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 5e 17 0b 00 41 83 e5 01 4c 8b 6c 24 60 75 07 e8 9e 13 0b 00 eb 41 f3 90 <48> b8 00 00 00 00 00 fc ff df 0f b6 04 03 84 c0 75 11 41 f7 04 24 RSP: 0018:ffffc900057ff7a0 EFLAGS: 00000293 RAX: ffffffff8180ee67 RBX: 1ffff1101730897d RCX: ffff888085833b80 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc900057ff9a0 R08: ffffffff8180ee32 R09: 1ffffffff20f6060 R10: dffffc0000000000 R11: fffffbfff20f6061 R12: ffff8880b9844be8 R13: ffff8880b993d0c8 R14: ffff8880b993d0c0 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffdfc989d28 CR3: 000000000d130000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1003 on_each_cpu include/linux/smp.h:71 [inline] text_poke_sync arch/x86/kernel/alternative.c:1938 [inline] text_poke_bp_batch+0x2d7/0x960 arch/x86/kernel/alternative.c:2148 text_poke_flush arch/x86/kernel/alternative.c:2339 [inline] text_poke_finish+0x1a/0x30 arch/x86/kernel/alternative.c:2346 arch_jump_label_transform_apply+0x17/0x30 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:831 process_one_work+0x92c/0x12c0 kernel/workqueue.c:2597 worker_thread+0xa63/0x1210 kernel/workqueue.c:2748 kthread+0x2b8/0x350 kernel/kthread.c:389 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308