rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P247/1:b..l (detected by 1, t=10502 jiffies, g=18089, q=52) task:kworker/u4:3 state:R running task stack:24096 pid: 247 ppid: 2 flags:0x00004000 Workqueue: netns cleanup_net Call Trace: context_switch kernel/sched/core.c:5030 [inline] __schedule+0x11b8/0x43b0 kernel/sched/core.c:6376 preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6780 irqentry_exit+0x63/0x70 kernel/entry/common.c:432 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:lock_acquire+0x1f2/0x3f0 kernel/locking/lockdep.c:5627 Code: 00 9c 8f 84 24 80 00 00 00 f6 84 24 81 00 00 00 02 0f 85 f6 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 44 3d 00 00 00 00 00 66 43 c7 44 3d 09 00 00 43 c6 44 3d 0b RSP: 0018:ffffc90002317900 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 3274ab4172a01d00 RDX: 0000000000000000 RSI: ffffffff8a0b2560 RDI: ffffffff8a59a340 RBP: ffffc90002317a20 R08: dffffc0000000000 R09: fffffbfff1ff3419 R10: fffffbfff1ff3419 R11: 1ffffffff1ff3418 R12: ffffffff8c11d9e0 R13: 1ffff92000462f2c R14: 0000000000000246 R15: dffffc0000000000 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:312 rcu_read_lock include/linux/rcupdate.h:739 [inline] inet_twsk_purge+0x119/0x810 net/ipv4/inet_timewait_sock.c:268 ops_exit_list net/core/net_namespace.c:177 [inline] cleanup_net+0x77b/0xb00 net/core/net_namespace.c:618 process_one_work+0x863/0x1000 kernel/workqueue.c:2310 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 rcu: rcu_preempt kthread starved for 10524 jiffies! g18089 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:27808 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5030 [inline] __schedule+0x11b8/0x43b0 kernel/sched/core.c:6376 schedule+0x11b/0x1e0 kernel/sched/core.c:6459 schedule_timeout+0x15c/0x280 kernel/time/timer.c:1914 rcu_gp_fqs_loop+0x29e/0x11b0 kernel/rcu/tree.c:1972 rcu_gp_kthread+0x98/0x350 kernel/rcu/tree.c:2145 kthread+0x436/0x520 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: 6099 Comm: syz.2.493 Not tainted 5.15.180-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:check_preemption_disabled+0x42/0x110 lib/smp_processor_id.c:55 Code: 65 8b 05 19 18 61 76 65 8b 0d 82 72 61 76 f7 c1 ff ff ff 7f 74 1f 65 48 8b 0c 25 28 00 00 00 48 3b 4c 24 08 0f 85 c4 00 00 00 <48> 83 c4 10 5b 41 5e 41 5f 5d c3 48 c7 04 24 00 00 00 00 9c 8f 04 RSP: 0018:ffffc900032ff5c8 EFLAGS: 00000046 RAX: 0000000000000000 RBX: 0000000000000001 RCX: d64cc1e7e3e3b200 RDX: 0000000000000002 RSI: ffffffff8a59a320 RDI: ffffffff8a59a2e0 RBP: 0000000000000000 R08: dffffc0000000000 R09: fffffbfff1ff3419 R10: fffffbfff1ff3419 R11: 1ffffffff1ff3418 R12: dffffc0000000000 R13: 0000000000000422 R14: 0000000000000000 R15: ffffffffa0018d54 FS: 00007f4633f196c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c356599 CR3: 0000000079908000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rcu_dynticks_curr_cpu_in_eqs kernel/rcu/tree.c:331 [inline] rcu_is_watching+0x11/0xa0 kernel/rcu/tree.c:1123 rcu_read_unlock include/linux/rcupdate.h:768 [inline] is_bpf_text_address+0x1d7/0x270 kernel/bpf/core.c:727 kernel_text_address kernel/extable.c:151 [inline] __kernel_text_address+0x9a/0x100 kernel/extable.c:105 unwind_get_return_address+0x49/0x80 arch/x86/kernel/unwind_orc.c:323 arch_stack_walk+0xf2/0x140 arch/x86/kernel/stacktrace.c:26 stack_trace_save+0x98/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:46 kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360 ____kasan_slab_free+0xd5/0x110 mm/kasan/common.c:366 kasan_slab_free include/linux/kasan.h:230 [inline] slab_free_hook mm/slub.c:1705 [inline] slab_free_freelist_hook+0xea/0x170 mm/slub.c:1731 slab_free mm/slub.c:3499 [inline] kmem_cache_free+0x8f/0x210 mm/slub.c:3515 __sigqueue_free kernel/signal.c:458 [inline] collect_signal kernel/signal.c:597 [inline] __dequeue_signal+0x4c4/0x5d0 kernel/signal.c:619 dequeue_signal+0xa2/0x440 kernel/signal.c:639 get_signal+0x6fe/0x12c0 kernel/signal.c:2781 arch_do_signal_or_restart+0xc1/0x1300 arch/x86/kernel/signal.c:867 handle_signal_work kernel/entry/common.c:154 [inline] exit_to_user_mode_loop+0x9e/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+0x16/0x40 kernel/entry/common.c:307 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f46360b1969 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:00007f4633f190e8 EFLAGS: 00000246 RAX: fffffffffffffffc RBX: 00007f46362d8fa8 RCX: 00007f46360b1969 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f46362d8fa8 RBP: 00007f46362d8fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f46362d8fac R13: 0000000000000000 R14: 00007fff67c4e420 R15: 00007fff67c4e508