rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (0 ticks this GP) idle=92e4/1/0x4000000000000000 softirq=195953/195953 fqs=3 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P28721/1:b..l rcu: (detected by 1, t=10502 jiffies, g=212985, q=320 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 28730 Comm: syz.6.5759 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:advance_sched+0x66e/0xd20 net/sched/sch_taprio.c:987 Code: 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 09 06 00 00 4d 89 af 50 01 00 00 48 8b 74 24 20 4c 89 fa 48 8b 7c 24 48 e8 f2 46 ff ff dd 18 6e f8 48 b8 00 00 00 00 00 fc ff df 48 8b 54 24 38 48 c1 RSP: 0018:ffffc90000007dd8 EFLAGS: 00000096 RAX: 0000000080010002 RBX: 0000000000000000 RCX: ffffffff8999e05d RDX: ffff88801d7b0000 RSI: ffffffff8999e1e1 RDI: ffff88801d7b0000 RBP: ffff888081666000 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000000 R13: 18b7dbdc53f7fe3c R14: ffff888081667400 R15: ffff888081667400 FS: 00007f8478d756c0(0000) GS:ffff888124387000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffc0af98f2b CR3: 000000007ea27000 CR4: 00000000003526f0 DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000002 DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: __run_hrtimer kernel/time/hrtimer.c:1930 [inline] __hrtimer_run_queues+0x470/0xa00 kernel/time/hrtimer.c:1994 hrtimer_interrupt+0x3e5/0x940 kernel/time/hrtimer.c:2113 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] __sysvec_apic_timer_interrupt+0x10b/0x460 arch/x86/kernel/apic/apic.c:1067 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline] sysvec_apic_timer_interrupt+0x9e/0xc0 arch/x86/kernel/apic/apic.c:1061 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:179 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x31/0x80 kernel/locking/spinlock.c:198 Code: f5 53 48 8b 74 24 10 48 89 fb 48 83 c7 18 e8 d6 1e 58 f6 48 89 df e8 ae 6e 58 f6 f7 c5 00 02 00 00 75 23 9c 58 f6 c4 02 75 37 01 00 00 00 e8 b5 3a 48 f6 65 8b 05 6e 1d 7d 08 85 c0 74 16 5b RSP: 0018:ffffc90005587b28 EFLAGS: 00000246 RAX: 0000000000000002 RBX: ffffffff9b194118 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff8df0fc2f RDI: ffffffff8c1c4780 RBP: 0000000000000286 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000800000000 R12: ffffffff9b193e80 R13: 0000000000000000 R14: ffffc90005587c80 R15: ffffffff9b19405c class_raw_spinlock_irqsave_destructor include/linux/spinlock.h:571 [inline] __do_adjtimex+0x892/0xe70 kernel/time/timekeeping.c:2871 do_adjtimex+0xa0/0x370 kernel/time/timekeeping.c:2914 do_clock_adjtime kernel/time/posix-timers.c:1154 [inline] __do_sys_clock_adjtime+0x177/0x290 kernel/time/posix-timers.c:1166 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f8477f9ce59 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:00007f8478d75028 EFLAGS: 00000246 ORIG_RAX: 0000000000000131 RAX: ffffffffffffffda RBX: 00007f8478215fa0 RCX: 00007f8477f9ce59 RDX: 0000000000000000 RSI: 0000200000000340 RDI: 0000000000000000 RBP: 00007f8478032d6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f8478216038 R14: 00007f8478215fa0 R15: 00007ffc0af981f8 task:syz.7.5757 state:R running task stack:26248 pid:28721 tgid:28720 ppid:19069 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1295/0x67a0 kernel/sched/core.c:7189 preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7513 irqentry_exit_to_kernel_mode_preempt include/linux/irq-entry-common.h:468 [inline] irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x205/0x970 kernel/entry/common.c:164 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:debug_lockdep_rcu_enabled+0x20/0x40 kernel/rcu/update.c:320 Code: 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 8b 05 22 99 4d 05 85 c0 74 20 8b 05 c0 cb 4d 05 85 c0 74 16 65 48 8b 05 e8 0d 80 08 <8b> 80 8c 0b 00 00 85 c0 0f 94 c0 0f b6 c0 c3 cc cc cc cc 66 2e 0f RSP: 0000:ffffc9000562ed28 EFLAGS: 00000202 RAX: ffff88803e6a4a80 RBX: ffffc9000562fa48 RCX: ffffffff9206b201 RDX: ffffc9000562fa50 RSI: ffffc9000562fa18 RDI: ffffc9000562edb0 RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000007 R10: 0000000000000200 R11: 0000000000085ce5 R12: ffffc9000562edf0 R13: ffffc9000562eda0 R14: ffffc9000562fa48 R15: ffffc9000562edd4 rcu_read_unlock include/linux/rcupdate.h:867 [inline] class_rcu_destructor include/linux/rcupdate.h:1181 [inline] unwind_next_frame+0x3a8/0x2090 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5296 [inline] __kmalloc_node_track_caller_noprof+0x304/0x850 mm/slub.c:5408 __kmemdup_nul mm/util.c:64 [inline] kstrdup+0x51/0xe0 mm/util.c:84 kstrdup_const+0x63/0x80 mm/util.c:104 __kernfs_new_node+0x9b/0x9f0 fs/kernfs/dir.c:660 kernfs_new_node+0x11b/0x1a0 fs/kernfs/dir.c:748 __kernfs_create_file+0x53/0x350 fs/kernfs/file.c:1057 sysfs_add_file_mode_ns+0x207/0x3c0 fs/sysfs/file.c:313 create_files fs/sysfs/group.c:82 [inline] internal_create_group+0x593/0xfb0 fs/sysfs/group.c:189 internal_create_groups+0x9d/0x150 fs/sysfs/group.c:229 setup_port+0x409/0x16e0 drivers/infiniband/core/sysfs.c:1202 ib_setup_port_attrs+0x201/0x600 drivers/infiniband/core/sysfs.c:1388 add_one_compat_dev+0x5b3/0x820 drivers/infiniband/core/device.c:978 rdma_dev_init_net+0x30a/0x590 drivers/infiniband/core/device.c:1194 ops_init+0x1e2/0x5f0 net/core/net_namespace.c:137 setup_net+0x118/0x3a0 net/core/net_namespace.c:446 copy_net_ns+0x46f/0x7c0 net/core/net_namespace.c:579 create_new_namespaces+0x3ea/0xac0 kernel/nsproxy.c:132 copy_namespaces+0x468/0x5e0 kernel/nsproxy.c:195 copy_process+0x3531/0x7ed0 kernel/fork.c:2267 kernel_clone+0x176/0x9e0 kernel/fork.c:2722 __do_sys_clone+0xd9/0x120 kernel/fork.c:2863 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f69c759ce59 RSP: 002b:00007f69c8405fd8 EFLAGS: 00000206 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007f69c7815fa0 RCX: 00007f69c759ce59 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000040000000 RBP: 00007f69c7632d6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 00007f69c7816038 R14: 00007f69c7815fa0 R15: 00007fffd38077b8 rcu: rcu_preempt kthread starved for 10496 jiffies! g212985 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:R running task stack:28216 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1295/0x67a0 kernel/sched/core.c:7189 __schedule_loop kernel/sched/core.c:7268 [inline] schedule+0xdd/0x390 kernel/sched/core.c:7283 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2297 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 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: 18079 Comm: kworker/u8:1 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:write_comp_data+0x2b/0x90 kernel/kcov.c:272 Code: 8b 05 b9 e5 00 12 49 89 f8 49 89 f1 49 89 d2 65 48 8b 3d 90 e5 00 12 a9 00 01 ff 00 74 1b f6 c4 01 74 07 a9 00 00 ff 00 74 05 00 12 84 09 8b 87 ec 16 00 00 85 c0 74 f1 8b 87 c8 16 00 00 83 RSP: 0018:ffffc900046e7868 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff81fc2dfd RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffff8880297b4a80 RBP: ffff8880b8443560 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000003 R13: ffffed10170886ad R14: 0000000000000001 R15: ffff8880b853c800 FS: 0000000000000000(0000) GS:ffff888124487000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f8afaf456b8 CR3: 000000000e596000 CR4: 00000000003526f0 DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000002 DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: csd_lock_wait kernel/smp.c:342 [inline] smp_call_function_many_cond+0x5ad/0x1700 kernel/smp.c:892 on_each_cpu_cond_mask+0x40/0x90 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+0x337/0xc60 arch/x86/kernel/alternative.c:2983 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 jump_label_update+0x37a/0x550 kernel/jump_label.c:910 static_key_enable_cpuslocked+0x1bc/0x270 kernel/jump_label.c:210 static_key_enable+0x1a/0x20 kernel/jump_label.c:223 toggle_allocation_gate mm/kfence/core.c:906 [inline] toggle_allocation_gate+0xfe/0x2d0 mm/kfence/core.c:898 process_one_work+0xa0e/0x1980 kernel/workqueue.c:3314 process_scheduled_works kernel/workqueue.c:3397 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3478 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245