rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4510/1:b..l (detected by 1, t=10502 jiffies, g=14009, q=151) task:kworker/u4:11 state:R running task stack:24504 pid: 4510 ppid: 2 flags:0x00004000 Workqueue: netns cleanup_net Call Trace: context_switch kernel/sched/core.c:5030 [inline] __schedule+0x12c4/0x45b0 kernel/sched/core.c:6376 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6780 irqentry_exit+0x53/0x80 kernel/entry/common.c:432 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:__preempt_count_add kernel/rcu/tree.c:1119 [inline] RIP: 0010:rcu_is_watching+0x4/0xa0 kernel/rcu/tree.c:1122 Code: 5d 41 5e 41 5f 5d c3 e8 0a d1 d4 08 41 f7 c4 00 02 00 00 75 b4 eb b3 e8 ea d0 d4 08 66 2e 0f 1f 84 00 00 00 00 00 41 57 41 56 <53> 65 ff 05 5c 21 97 7e e8 8f e4 d4 08 89 c3 83 f8 08 73 72 49 bf RSP: 0018:ffffc9000313f8a8 EFLAGS: 00000257 RAX: 0000000000000001 RBX: 0000000000000001 RCX: ffffffff8162e2bc RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8e0aa6e8 RBP: ffffc9000313fa20 R08: dffffc0000000000 R09: fffffbfff1c154de R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff92000627f20 R13: dffffc0000000000 R14: 0000000000000000 R15: ffff88802d1fc3d0 trace_lock_acquire include/trace/events/lock.h:13 [inline] lock_acquire+0xdd/0x4f0 kernel/locking/lockdep.c:5594 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:312 rcu_read_lock include/linux/rcupdate.h:739 [inline] inet_twsk_purge+0x129/0x9e0 net/ipv4/inet_timewait_sock.c:268 ops_exit_list net/core/net_namespace.c:177 [inline] cleanup_net+0x886/0xc90 net/core/net_namespace.c:618 process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310 worker_thread+0xaca/0x1280 kernel/workqueue.c:2457 kthread+0x3f6/0x4f0 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 rcu: rcu_preempt kthread timer wakeup didn't happen for 10527 jiffies! g14009 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=6292 rcu: rcu_preempt kthread starved for 10533 jiffies! g14009 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27000 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5030 [inline] __schedule+0x12c4/0x45b0 kernel/sched/core.c:6376 schedule+0x11b/0x1f0 kernel/sched/core.c:6459 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1914 rcu_gp_fqs_loop+0x2bf/0x1080 kernel/rcu/tree.c:1972 rcu_gp_kthread+0xa4/0x360 kernel/rcu/tree.c:2145 kthread+0x3f6/0x4f0 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 5176 Comm: syz.2.202 Not tainted 5.15.180-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:29 [inline] RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:70 [inline] RIP: 0010:lockdep_hardirqs_off+0x45/0x100 kernel/locking/lockdep.c:4370 Code: 00 0f 84 8d 00 00 00 49 89 fe 65 8b 05 fc 4e c2 75 a9 00 00 f0 00 74 65 83 3d a6 5e 69 0c 00 75 15 48 c7 04 24 00 00 00 00 9c <8f> 04 24 f7 04 24 00 02 00 00 75 76 65 8b 05 38 55 c2 75 85 c0 74 RSP: 0018:ffffc900031bfac0 EFLAGS: 00000046 RAX: 0000000000000000 RBX: 0000000000000040 RCX: ffffffff8a600f57 RDX: 0000000000000000 RSI: ffffffff8aab2b80 RDI: ffffffff8af9fc80 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: ffffffff8a4012aa R15: 0000000000000000 FS: 00007f8784bfb6c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fa24dba4f98 CR3: 000000007d9db000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: irqentry_enter+0x27/0x50 kernel/entry/common.c:-1 sysvec_apic_timer_interrupt+0xa/0xc0 arch/x86/kernel/apic/apic.c:1108 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline] RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:202 Code: 31 60 f6 ff 90 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 ee 48 19 f7 48 89 df e8 46 9d 1a f7 e8 31 5d 3d f7 fb bf 01 00 00 00 16 e0 0d f7 65 8b 05 87 b0 b8 75 85 c0 74 02 5b c3 e8 54 cd b6 RSP: 0018:ffffc900031bfbc0 EFLAGS: 00000282 RAX: a50821decee9ad00 RBX: ffff888025aae5c0 RCX: ffffffff96a97f03 RDX: dffffc0000000000 RSI: ffffffff8aab2b60 RDI: 0000000000000001 RBP: 0000000000000000 R08: ffffffff81871c90 R09: ffffed1004b55cb9 R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000011 R13: dffffc0000000000 R14: ffff888025aae858 R15: ffff888025aae5c0 spin_unlock_irq include/linux/spinlock.h:413 [inline] get_signal+0x13ee/0x14e0 kernel/signal.c:2903 arch_do_signal_or_restart+0xc3/0x1890 arch/x86/kernel/signal.c:867 handle_signal_work kernel/entry/common.c:154 [inline] exit_to_user_mode_loop+0x97/0x130 kernel/entry/common.c:178 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:214 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline] syscall_exit_to_user_mode+0x5d/0x240 kernel/entry/common.c:307 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f8786d92169 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f8784bfb0e8 EFLAGS: 00000246 RAX: fffffffffffffffc RBX: 00007f8786faafa8 RCX: 00007f8786d92169 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f8786faafa8 RBP: 00007f8786faafa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f8786faafac R13: 0000000000000000 R14: 00007ffda785e380 R15: 00007ffda785e468