rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P24178/1:b..l rcu: (detected by 0, t=10502 jiffies, g=166749, q=293 ncpus=2) task:syz.1.3819 state:R running task stack:25128 pid:24178 tgid:24176 ppid:20092 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1821/0x5740 kernel/sched/core.c:7189 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7513 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x14f/0x760 kernel/entry/common.c:164 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:kasan_save_stack mm/kasan/common.c:57 [inline] RIP: 0010:kasan_save_track+0x32/0x80 mm/kasan/common.c:78 Code: 41 57 41 56 53 48 83 e4 f0 48 81 ec 10 02 00 00 89 f3 49 89 fe 49 89 e7 ba 00 02 00 00 4c 89 ff 31 f6 e8 81 80 78 09 4c 89 ff 40 00 00 00 31 d2 e8 92 24 80 ff 4c 89 ff 89 c6 89 da b9 01 00 RSP: 0018:ffffc9000542ef50 EFLAGS: 00000246 RAX: ffffc9000542ef50 RBX: 0000000000002920 RCX: 0000000000000000 RDX: 0000000000000200 RSI: 0000000000000000 RDI: ffffc9000542ef50 RBP: ffffc9000542f178 R08: dffffc0000000000 R09: ffffc9000542ef50 R10: dffffc0000000000 R11: ffffed100bf428cb R12: 0000000000000020 R13: ffff88801ea9de00 R14: ffff88801ea9de20 R15: ffffc9000542ef50 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __kmalloc_cache_noprof+0x31c/0x660 mm/slub.c:5419 kmalloc_noprof include/linux/slab.h:950 [inline] kzalloc_noprof include/linux/slab.h:1188 [inline] ref_tracker_alloc+0x15a/0x4c0 lib/ref_tracker.c:270 __netdev_tracker_alloc include/linux/netdevice.h:4471 [inline] netdev_hold include/linux/netdevice.h:4500 [inline] dst_init+0xd9/0x480 net/core/dst.c:52 dst_alloc+0x12a/0x170 net/core/dst.c:94 rt_dst_alloc net/ipv4/route.c:1651 [inline] __mkroute_output net/ipv4/route.c:2655 [inline] ip_route_output_key_hash_rcu+0x14d0/0x25d0 net/ipv4/route.c:2875 ip_route_output_key_hash+0x18d/0x2a0 net/ipv4/route.c:2705 __ip_route_output_key include/net/route.h:169 [inline] ip_route_output_flow+0x2a/0x150 net/ipv4/route.c:2932 udp_sendmsg+0x141a/0x21a0 net/ipv4/udp.c:1409 sock_sendmsg_nosec net/socket.c:787 [inline] __sock_sendmsg net/socket.c:802 [inline] ____sys_sendmsg+0x80a/0x9f0 net/socket.c:2698 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2752 __sys_sendmmsg+0x27c/0x4e0 net/socket.c:2841 __do_sys_sendmmsg net/socket.c:2868 [inline] __se_sys_sendmmsg net/socket.c:2865 [inline] __x64_sys_sendmmsg+0xa0/0xc0 net/socket.c:2865 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fd09439ce59 RSP: 002b:00007fd09531b028 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 00007fd094615fa0 RCX: 00007fd09439ce59 RDX: 000000000800001d RSI: 0000200000007fc0 RDI: 0000000000000004 RBP: 00007fd094432d6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fd094616038 R14: 00007fd094615fa0 R15: 00007ffed11b2af8 rcu: rcu_preempt kthread starved for 10458 jiffies! g166749 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:27544 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1821/0x5740 kernel/sched/core.c:7189 __schedule_loop kernel/sched/core.c:7268 [inline] schedule+0x164/0x360 kernel/sched/core.c:7283 schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x312/0x11d0 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2297 kthread+0x389/0x470 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: 0 UID: 0 PID: 16307 Comm: kworker/u8:17 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:get_current arch/x86/include/asm/current.h:25 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x8/0x70 kernel/kcov.c:216 Code: 8b 3d 54 fb 60 0c 48 89 de 5b e9 03 ed 5f 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 8b 04 24 <65> 48 8b 0d 38 ab 73 11 65 8b 15 59 ab 73 11 81 e2 00 01 ff 00 74 RSP: 0018:ffffc90002f276f8 EFLAGS: 00000202 RAX: ffffffff81b9c2b6 RBX: ffff8880b863c148 RCX: ffff888056fbbd80 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90002f27840 R08: ffffffff9030ccf7 R09: 1ffffffff206199e R10: dffffc0000000000 R11: fffffbfff206199f R12: 1ffff110170e8169 R13: dffffc0000000000 R14: ffff8880b8740b48 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff888125289000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fe7ccb55e9c CR3: 000000000e74a000 CR4: 0000000000350ef0 Call Trace: csd_lock_wait kernel/smp.c:342 [inline] smp_call_function_many_cond+0xfe6/0x13d0 kernel/smp.c:892 on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1057 on_each_cpu include/linux/smp.h:72 [inline] smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2773 [inline] smp_text_poke_batch_finish+0x5f5/0x1160 arch/x86/kernel/alternative.c:2983 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 static_key_enable_cpuslocked+0x128/0x240 kernel/jump_label.c:210 static_key_enable+0x1a/0x20 kernel/jump_label.c:223 toggle_allocation_gate+0xab/0x290 mm/kfence/core.c:906 process_one_work kernel/workqueue.c:3314 [inline] process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3397 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3478 kthread+0x389/0x470 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