rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P14880/1:b..l rcu: (detected by 1, t=10506 jiffies, g=91241, q=258 ncpus=2) task:syz.2.2367 state:R running task stack:25608 pid:14880 tgid:14878 ppid:5621 task_flags:0x400140 flags:0x00080002 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:lock_acquire+0x5e/0x370 kernel/locking/lockdep.c:5872 Code: 05 3b 05 25 12 83 f8 07 0f 87 d9 02 00 00 48 0f a3 05 46 8e f2 0e 0f 82 a4 02 00 00 8b 35 ce c1 f2 0e 85 f6 0f 85 bf 00 00 00 <48> 8b 44 24 30 65 48 2b 05 dd 04 25 12 0f 85 ed 02 00 00 48 83 c4 RSP: 0018:ffffc90005157750 EFLAGS: 00000206 RAX: 0000000000000046 RBX: 0000000000000000 RCX: 0000000000000004 RDX: 0000000000000000 RSI: ffffffff8deea697 RDI: ffffffff8c1c4680 RBP: ffffffff8e7e5560 R08: 0000000053e37fd0 R09: 0000000000000007 R10: 0000000000000200 R11: 0000000000000000 R12: 0000000000000002 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:300 [inline] rcu_read_lock include/linux/rcupdate.h:838 [inline] class_rcu_constructor include/linux/rcupdate.h:1181 [inline] kernfs_root+0x34/0x2a0 fs/kernfs/kernfs-internal.h:74 kernfs_activate fs/kernfs/dir.c:1461 [inline] kernfs_add_one+0x540/0x850 fs/kernfs/dir.c:869 __kernfs_create_file+0x295/0x350 fs/kernfs/file.c:1086 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_gid_attrs drivers/infiniband/core/sysfs.c:1118 [inline] ib_setup_port_attrs+0x41f/0x600 drivers/infiniband/core/sysfs.c:1394 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 unshare_nsproxy_namespaces+0xf2/0x220 kernel/nsproxy.c:234 ksys_unshare+0x438/0xab0 kernel/fork.c:3242 __do_sys_unshare kernel/fork.c:3316 [inline] __se_sys_unshare kernel/fork.c:3314 [inline] __x64_sys_unshare+0x31/0x40 kernel/fork.c:3314 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: 0033:0x7f8e2e39ce59 RSP: 002b:00007f8e2f262028 EFLAGS: 00000246 ORIG_RAX: 0000000000000110 RAX: ffffffffffffffda RBX: 00007f8e2e615fa0 RCX: 00007f8e2e39ce59 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000006a040000 RBP: 00007f8e2e432d6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f8e2e616038 R14: 00007f8e2e615fa0 R15: 00007ffead077008 rcu: rcu_preempt kthread timer wakeup didn't happen for 10505 jiffies! g91241 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=67545 rcu: rcu_preempt kthread starved for 10506 jiffies! g91241 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27752 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: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 5615 Comm: syz-executor Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:__lock_acquire+0xbd/0x2630 kernel/locking/lockdep.c:5141 Code: 89 d8 0f 87 42 1e 00 00 49 8b 44 c2 08 48 85 c0 0f 84 08 03 00 00 8b 8d 88 0b 00 00 83 f9 2f 76 09 45 84 ed 0f 85 53 10 00 00 <48> 2d 60 5b 10 96 49 89 c5 48 b8 29 5c 8f c2 f5 28 5c 8f 49 c1 fd RSP: 0018:ffffc90000007c80 EFLAGS: 00000093 RAX: ffffffff961bc158 RBX: 0000000000000000 RCX: 0000000000000008 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88802a34e2c0 RBP: ffff888073c74a80 R08: 0000000000000001 R09: 0000000000000001 R10: ffff88802a34e2c0 R11: 0000000000000001 R12: 0000000000000000 R13: 000000009b5ef001 R14: 0000000000000000 R15: 0000000000000000 FS: 0000555558952500(0000) GS:ffff888124387000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000001280 CR3: 000000005a6e2000 CR4: 00000000003526f0 DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000002 DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x1b1/0x370 kernel/locking/lockdep.c:5825 __raw_spin_lock include/linux/spinlock_api_smp.h:158 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:158 spin_lock include/linux/spinlock.h:342 [inline] advance_sched+0xe5/0xd20 net/sched/sch_taprio.c:930 __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:lock_acquire+0x5e/0x370 kernel/locking/lockdep.c:5872 Code: 05 3b 05 25 12 83 f8 07 0f 87 d9 02 00 00 48 0f a3 05 46 8e f2 0e 0f 82 a4 02 00 00 8b 35 ce c1 f2 0e 85 f6 0f 85 bf 00 00 00 <48> 8b 44 24 30 65 48 2b 05 dd 04 25 12 0f 85 ed 02 00 00 48 83 c4 RSP: 0018:ffffc9000442f3d8 EFLAGS: 00000206 RAX: 0000000000000046 RBX: 0000000000000000 RCX: 0000000000000007 RDX: 0000000000000000 RSI: ffffffff8deea697 RDI: ffffffff8c1c4680 RBP: ffffffff8e7e54a0 R08: 0000000005916a72 R09: 000000000000001e R10: 0000000000000200 R11: 0000000000000000 R12: 0000000000000002 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:300 [inline] rcu_read_lock_sched include/linux/rcupdate.h:936 [inline] pfn_valid include/linux/mmzone.h:2281 [inline] page_table_check_set+0x6b/0x920 mm/page_table_check.c:105 __page_table_check_ptes_set+0x27a/0x4e0 mm/page_table_check.c:212 page_table_check_ptes_set include/linux/page_table_check.h:83 [inline] set_ptes include/linux/pgtable.h:413 [inline] __copy_present_ptes mm/memory.c:1118 [inline] copy_present_ptes mm/memory.c:1197 [inline] copy_pte_range mm/memory.c:1320 [inline] copy_pmd_range mm/memory.c:1408 [inline] copy_pud_range mm/memory.c:1445 [inline] copy_p4d_range mm/memory.c:1469 [inline] copy_page_range+0x2197/0x5b20 mm/memory.c:1555 dup_mmap+0xd44/0x21b0 mm/mmap.c:1840 dup_mm kernel/fork.c:1534 [inline] copy_mm kernel/fork.c:1586 [inline] copy_process+0x6c78/0x7ed0 kernel/fork.c:2264 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: 0033:0x7f19e63c58d2 Code: 89 e7 e8 71 8b f7 ff 45 31 c0 31 d2 31 f6 64 48 8b 04 25 10 00 00 00 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 66 89 c5 85 c0 75 3b 64 48 8b 04 25 10 00 00 RSP: 002b:00007fff2fa6fbe0 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007fff2fa6fbe0 RCX: 00007f19e63c58d2 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 00007fff2fa6fd6c R08: 0000000000000000 R09: 0000000000000001 R10: 00005555589527d0 R11: 0000000000000246 R12: 0000000000000001 R13: 00000000000927c0 R14: 00000000000e1500 R15: 00007fff2fa6fdc0