rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P1119/3:b..l rcu: (detected by 1, t=10502 jiffies, g=83169, q=9347 ncpus=2) task:kworker/u8:9 state:R running task stack:20440 pid:1119 tgid:1119 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: tipc_send tipc_conn_send_work Call Trace: context_switch kernel/sched/core.c:5520 [inline] __schedule+0x16d9/0x5700 kernel/sched/core.c:7270 preempt_schedule_irq+0x4b/0x90 kernel/sched/core.c:7592 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x14f/0x910 kernel/entry/common.c:167 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:lock_acquire+0x232/0x350 kernel/locking/lockdep.c:5913 Code: ff ff ff e8 30 9f b3 09 f7 44 24 10 00 02 00 00 0f 84 38 ff ff ff 65 48 8b 05 62 ea 02 11 48 3b 44 24 50 75 33 fb 48 83 c4 58 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 ff 72 b7 09 cc 48 8d 3d 27 2f 13 RSP: 0018:ffffc90006826aa0 EFLAGS: 00000296 RAX: c870e9cdcf2e8500 RBX: 0000000000000000 RCX: 0000000000000046 RDX: 00000000d1d2af13 RSI: ffffffff8db3b494 RDI: ffffffff8bcc2080 RBP: ffff8880288abe80 R08: 8a00000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: ffffffff8e1c3ac0 R12: ffffffff8e1c3ac0 R13: 0000000000000002 R14: 0000000000000000 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:309 [inline] rcu_read_lock include/linux/rcupdate.h:849 [inline] class_rcu_constructor include/linux/rcupdate.h:1216 [inline] unwind_next_frame+0xac/0x2550 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2748 [inline] slab_free mm/slub.c:6499 [inline] kfree+0x1c5/0x6d0 mm/slub.c:6792 skb_kfree_head net/core/skbuff.c:1083 [inline] skb_free_head net/core/skbuff.c:1095 [inline] skb_release_data+0x85e/0xab0 net/core/skbuff.c:1122 skb_release_all net/core/skbuff.c:1197 [inline] __kfree_skb+0x5d/0x210 net/core/skbuff.c:1211 kfree_skb_reason include/linux/skbuff.h:1323 [inline] kfree_skb include/linux/skbuff.h:1332 [inline] tipc_sk_proto_rcv+0x7a1/0x1810 net/tipc/socket.c:2185 tipc_sk_filter_rcv+0x3005/0x3240 net/tipc/socket.c:2357 tipc_sk_enqueue net/tipc/socket.c:2450 [inline] tipc_sk_rcv+0x8c4/0x2b30 net/tipc/socket.c:2502 tipc_topsrv_kern_evt net/tipc/topsrv.c:630 [inline] tipc_conn_send_to_sock net/tipc/topsrv.c:286 [inline] tipc_conn_send_work+0x6cd/0xa50 net/tipc/topsrv.c:306 process_one_work kernel/workqueue.c:3396 [inline] process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3479 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3560 kthread+0x38b/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: rcu_preempt kthread timer wakeup didn't happen for 6462 jiffies! g83169 f0x0 RCU_GP_WAIT_FQS(5) ->state=I rcu: Possible timer handling issue on cpu=1 timer-softirq=45381 rcu: rcu_preempt kthread starved for 6463 jiffies! g83169 f0x0 RCU_GP_WAIT_FQS(5) ->state=I ->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:I stack:27784 pid:18 tgid:18 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5520 [inline] __schedule+0x16d9/0x5700 kernel/sched/core.c:7270 __schedule_loop kernel/sched/core.c:7347 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7362 schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x30c/0x11f0 kernel/rcu/tree.c:2122 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2330 kthread+0x38b/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 UID: 0 PID: 15320 Comm: syz.0.3193 Tainted: G L syzkaller #0 PREEMPT_{RT,(full)} Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 RIP: 0010:__sanitizer_cov_trace_const_cmp2+0x0/0xb0 kernel/kcov.c:302 Code: 89 7c 0a 10 48 89 74 0a 18 48 89 44 0a 20 c3 cc cc cc cc cc 66 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 48 8b 04 24 65 48 8b 0d e8 21 de 10 65 48 8b 15 e8 21 RSP: 0018:ffffc900044ef218 EFLAGS: 00000246 RAX: ffff888063b211ca RBX: 0000000000000004 RCX: ffff88801fb5be80 RDX: 0000000000000002 RSI: 0000000000000004 RDI: 0000000000000004 RBP: ffffc900044ef310 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000100 R11: 0000000000000003 R12: ffff888028942e10 R13: dffffc0000000000 R14: 1ffff1100c764239 R15: ffff888068d70000 FS: 00007f0d579056c0(0000) GS:ffff888125cd6000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055c994c8ca90 CR3: 000000003848e000 CR4: 00000000003526f0 Call Trace: memcmp include/linux/fortify-string.h:675 [inline] rhashtable_compare include/linux/rhashtable.h:607 [inline] __rhashtable_lookup include/linux/rhashtable.h:635 [inline] rhashtable_lookup include/linux/rhashtable.h:672 [inline] tipc_sk_lookup+0x36c/0x920 net/tipc/socket.c:3005 tipc_sk_rcv+0x45d/0x2b30 net/tipc/socket.c:2497 tipc_node_xmit+0x218/0xf10 net/tipc/node.c:1706 tipc_node_xmit_skb net/tipc/node.c:1771 [inline] tipc_node_distr_xmit+0x2da/0x420 net/tipc/node.c:1786 tipc_group_join+0x571/0x710 net/tipc/group.c:208 tipc_sk_join+0x480/0x6a0 net/tipc/socket.c:3107 tipc_setsockopt+0x73e/0x9a0 net/tipc/socket.c:3205 do_sock_setsockopt+0x17c/0x1b0 net/socket.c:2397 __sys_setsockopt net/socket.c:2422 [inline] __do_sys_setsockopt net/socket.c:2428 [inline] __se_sys_setsockopt net/socket.c:2425 [inline] __x64_sys_setsockopt+0x143/0x1b0 net/socket.c:2425 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f0d596ce159 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f0d57905028 EFLAGS: 00000246 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 00007f0d59956090 RCX: 00007f0d596ce159 RDX: 0000000000000087 RSI: 000000000000010f RDI: 0000000000000006 RBP: 00007f0d59765024 R08: 0000000000000010 R09: 0000000000000000 R10: 0000200000000440 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f0d59956128 R14: 00007f0d59956090 R15: 00007ffea795e768