rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P13919/1:b..l rcu: (detected by 1, t=10502 jiffies, g=54569, q=345 ncpus=2) task:syz-executor state:R running task stack:21248 pid:13919 tgid:13919 ppid:13912 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5260 [inline] __schedule+0x14ef/0x4fb0 kernel/sched/core.c:6867 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7194 irqentry_exit+0x597/0x620 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:queue_work_on+0x162/0x1c0 kernel/workqueue.c:2391 Code: 00 4d 85 ed 75 16 e8 5d 48 37 00 eb 15 e8 56 48 37 00 e8 11 5e ed 09 4d 85 ed 74 ea e8 47 48 37 00 fb 65 48 8b 05 fe 4e 44 11 <48> 3b 44 24 18 75 48 89 d8 48 83 c4 20 5b 41 5c 41 5d 41 5e 41 5f RSP: 0018:ffffc9000ab56eb0 EFLAGS: 00000293 RAX: 54bff6ac30274c00 RBX: ffff88807619e301 RCX: ffff88802b5b3d00 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000008 R08: ffffffff8fceef77 R09: 1ffffffff1f9ddee R10: dffffc0000000000 R11: fffffbfff1f9ddef R12: 0000000000000000 R13: 0000000000000200 R14: 0000000000000000 R15: 0000000000800001 queue_work include/linux/workqueue.h:669 [inline] schedule_work include/linux/workqueue.h:730 [inline] nsim_fib_event_schedule_work drivers/net/netdevsim/fib.c:-1 [inline] nsim_fib_event_nb+0xe0d/0x1080 drivers/net/netdevsim/fib.c:1043 notifier_call_chain+0x19d/0x3a0 kernel/notifier.c:85 atomic_notifier_call_chain+0xda/0x180 kernel/notifier.c:223 call_fib_notifiers+0x31/0x60 net/core/fib_notifier.c:35 call_fib_entry_notifiers+0x158/0x200 net/ipv4/fib_trie.c:107 fib_table_insert+0xcce/0x1b50 net/ipv4/fib_trie.c:1370 fib_magic+0x2e4/0x3d0 net/ipv4/fib_frontend.c:1134 fib_add_ifaddr+0x144/0x5f0 net/ipv4/fib_frontend.c:1156 fib_inetaddr_event+0x12e/0x190 net/ipv4/fib_frontend.c:1470 notifier_call_chain+0x19d/0x3a0 kernel/notifier.c:85 blocking_notifier_call_chain+0x6a/0x90 kernel/notifier.c:380 __inet_insert_ifa+0x9e9/0xbc0 net/ipv4/devinet.c:566 inet_rtm_newaddr+0x10d8/0x1ad0 net/ipv4/devinet.c:1001 rtnetlink_rcv_msg+0x7d5/0xbe0 net/core/rtnetlink.c:6958 netlink_rcv_skb+0x232/0x4b0 net/netlink/af_netlink.c:2550 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x80f/0x9b0 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg+0x21c/0x270 net/socket.c:742 __sys_sendto+0x3c0/0x550 net/socket.c:2206 __do_sys_sendto net/socket.c:2213 [inline] __se_sys_sendto net/socket.c:2209 [inline] __x64_sys_sendto+0xde/0x100 net/socket.c:2209 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f792cd5b58e RSP: 002b:00007ffebc0b1a88 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 000055555f9ec500 RCX: 00007f792cd5b58e RDX: 0000000000000028 RSI: 00007f792db44670 RDI: 0000000000000003 RBP: 0000000000000001 R08: 00007ffebc0b1b04 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003 R13: 0000000000000000 R14: 00007f792db44670 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 10557 jiffies! g54569 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:27824 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5260 [inline] __schedule+0x14ef/0x4fb0 kernel/sched/core.c:6867 __schedule_loop kernel/sched/core.c:6949 [inline] schedule+0x164/0x360 kernel/sched/core.c:6964 schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x312/0x1560 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x9d/0x3b0 kernel/rcu/tree.c:2285 kthread+0x726/0x8b0 kernel/kthread.c:463 ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82 Code: 28 5f 02 e9 fe 95 97 f5 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d d3 b7 10 00 fb f4 d7 95 97 f5 cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 RSP: 0018:ffffffff8e007dc0 EFLAGS: 00000246 RAX: 0000000001d20a5f RBX: ffffffff8198427d RCX: 0000000080000001 RDX: 0000000000000001 RSI: ffffffff8dacfb53 RDI: ffffffff8be73880 RBP: ffffffff8e007eb0 R08: ffff8880b86336db R09: 1ffff110170c66db R10: dffffc0000000000 R11: ffffed10170c66dc R12: ffffffff8fceef70 R13: 1ffffffff1c12a78 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888125926000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f09331858e0 CR3: 0000000027e0f000 CR4: 0000000000350ef0 Call Trace: arch_safe_halt arch/x86/kernel/process.c:766 [inline] default_idle+0x9/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x72/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:191 [inline] do_idle+0x1bd/0x500 kernel/sched/idle.c:332 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:430 rest_init+0x2de/0x300 init/main.c:757 start_kernel+0x380/0x3d0 init/main.c:1206 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310 x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291 common_startup_64+0x13e/0x147