rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P21708/1:b..l P20857/1:b..l rcu: (detected by 1, t=10503 jiffies, g=155733, q=391 ncpus=2) task:syz-executor state:R running task stack:21592 pid:20857 tgid:20857 ppid:20839 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5282 [inline] __schedule+0x14db/0x5030 kernel/sched/core.c:6894 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7221 irqentry_exit+0x5e3/0x670 kernel/entry/common.c:216 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:unwind_next_frame+0x183/0x23d0 arch/x86/kernel/unwind_orc.c:-1 Code: ec 18 00 00 49 8d 5e 35 48 89 d8 48 c1 e8 03 48 89 44 24 28 0f b6 04 28 84 c0 0f 85 4c 1b 00 00 4c 89 6c 24 48 4c 89 64 24 20 <4c> 89 7c 24 50 48 89 5c 24 18 0f b6 1b 48 8b 44 24 30 80 3c 28 00 RSP: 0018:ffffc90013d3f598 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffffc90013d3f6fd RCX: 0000000080000001 RDX: 0000000012413615 RSI: ffffffff8be09d40 RDI: ffffffff8be09d00 RBP: dffffc0000000000 R08: ffffffff81745df5 R09: ffffffff8e144f60 R10: ffffc90013d3f718 R11: fffff520027a7ee5 R12: 1ffff920027a7ed9 R13: ffffc90013d3f718 R14: ffffc90013d3f6c8 R15: ffffffff81745df5 __unwind_start+0x5b9/0x760 arch/x86/kernel/unwind_orc.c:773 unwind_start arch/x86/include/asm/unwind.h:64 [inline] arch_stack_walk+0xe4/0x150 arch/x86/kernel/stacktrace.c:24 stack_trace_save+0x9c/0xe0 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+0x46/0x50 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:2768 [inline] slab_free mm/slub.c:6907 [inline] kfree+0x1be/0x670 mm/slub.c:7205 ref_tracker_free+0x4dd/0x7d0 lib/ref_tracker.c:340 __netns_tracker_free include/net/net_namespace.h:379 [inline] put_net_track include/net/net_namespace.h:394 [inline] __sk_destruct+0x3c7/0x880 net/core/sock.c:2379 sock_put include/net/sock.h:1998 [inline] unix_release_sock+0xa36/0xc70 net/unix/af_unix.c:732 unix_release+0x92/0xd0 net/unix/af_unix.c:1184 __sock_release+0xb9/0x250 net/socket.c:666 sock_close+0x1c/0x30 net/socket.c:1470 __fput+0x44c/0xa70 fs/file_table.c:468 fput_close_sync+0x113/0x220 fs/file_table.c:573 __do_sys_close fs/open.c:1509 [inline] __se_sys_close fs/open.c:1494 [inline] __x64_sys_close+0x7f/0x110 fs/open.c:1494 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f7a5758eea7 RSP: 002b:00007fff7eb4df98 EFLAGS: 00000246 ORIG_RAX: 0000000000000003 RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 00007f7a5758eea7 RDX: 0000000000000000 RSI: 0000000000008933 RDI: 0000000000000005 RBP: 00007fff7eb4dfa0 R08: 0000000000000002 R09: 007061747663616d R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003 R13: 00007f7a58314620 R14: 0000000000000006 R15: 0000000000000000 task:syz-executor state:R running task stack:22392 pid:21708 tgid:21708 ppid:21689 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5282 [inline] __schedule+0x14db/0x5030 kernel/sched/core.c:6894 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7221 irqentry_exit+0x5e3/0x670 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:rcu_is_watching+0x67/0xb0 kernel/rcu/tree.c:753 Code: 89 f7 e8 3c d0 80 00 48 c7 c3 58 c7 a3 92 49 03 1e 48 89 d8 48 c1 e8 03 42 0f b6 04 38 84 c0 75 34 8b 03 65 ff 0d a9 6e fb 10 <74> 11 83 e0 04 c1 e8 02 5b 41 5e 41 5f e9 87 8e ba 09 cc e8 11 56 RSP: 0018:ffffc90004726558 EFLAGS: 00000286 RAX: 0000000000e2e8b4 RBX: ffff8880b8633758 RCX: 0000000080000001 RDX: ffffc90004726601 RSI: ffffffff8be09d40 RDI: ffffffff8be09d00 RBP: dffffc0000000000 R08: ffffc900047278f0 R09: 0000000000000000 R10: ffffc90004726698 R11: fffff520008e4cd5 R12: ffffc90004727900 R13: ffffc90004720000 R14: ffffffff8dbc4dd0 R15: dffffc0000000000 rcu_read_unlock include/linux/rcupdate.h:879 [inline] class_rcu_destructor include/linux/rcupdate.h:1193 [inline] unwind_next_frame+0x1a6d/0x23d0 arch/x86/kernel/unwind_orc.c:695 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:5187 [inline] slab_alloc_node mm/slub.c:5500 [inline] kmem_cache_alloc_noprof+0x37d/0x710 mm/slub.c:5507 __kernfs_new_node+0xdc/0x8a0 fs/kernfs/dir.c:637 kernfs_new_node+0x102/0x210 fs/kernfs/dir.c:718 __kernfs_create_file+0x4b/0x2e0 fs/kernfs/file.c:1057 sysfs_add_file_mode_ns+0x238/0x300 fs/sysfs/file.c:313 create_files fs/sysfs/group.c:82 [inline] internal_create_group+0x667/0x1170 fs/sysfs/group.c:189 internal_create_groups fs/sysfs/group.c:229 [inline] sysfs_create_groups+0x59/0x120 fs/sysfs/group.c:255 device_add_groups drivers/base/core.c:2836 [inline] device_add_attrs+0x1c4/0x5a0 drivers/base/core.c:2911 device_add+0x496/0xb80 drivers/base/core.c:3643 netdev_register_kobject+0x178/0x310 net/core/net-sysfs.c:2358 register_netdevice+0x124f/0x1a70 net/core/dev.c:11406 rtnl_newlink_create+0x31f/0xb00 net/core/rtnetlink.c:3842 __rtnl_newlink net/core/rtnetlink.c:3957 [inline] rtnl_newlink+0x16e7/0x1c90 net/core/rtnetlink.c:4072 rtnetlink_rcv_msg+0x7cf/0xb70 net/core/rtnetlink.c:6958 netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2550 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec+0x18f/0x1d0 net/socket.c:737 __sock_sendmsg net/socket.c:752 [inline] __sys_sendto+0x3ce/0x540 net/socket.c:2221 __do_sys_sendto net/socket.c:2228 [inline] __se_sys_sendto net/socket.c:2224 [inline] __x64_sys_sendto+0xde/0x100 net/socket.c:2224 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f5fc95915dc RSP: 002b:00007fff9d655df0 EFLAGS: 00000293 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007f5fca314620 RCX: 00007f5fc95915dc RDX: 000000000000003c RSI: 00007f5fca314670 RDI: 0000000000000003 RBP: 0000000000000000 R08: 00007fff9d655e44 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003 R13: 0000000000000000 R14: 00007f5fca314670 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 10618 jiffies! g155733 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:27576 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5282 [inline] __schedule+0x14db/0x5030 kernel/sched/core.c:6894 __schedule_loop kernel/sched/core.c:6976 [inline] schedule+0x165/0x360 kernel/sched/core.c:6991 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x11b0 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x9b/0x2d0 kernel/rcu/tree.c:2297 kthread+0x389/0x480 kernel/kthread.c:467 ret_from_fork+0x510/0xa50 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+0x13/0x20 arch/x86/kernel/paravirt.c:82 Code: cc cc cc cc 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 e3 8f 29 00 f3 0f 1e fa fb f4 cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffffff8de07dc0 EFLAGS: 000002c2 RAX: 0000000001a41935 RBX: ffffffff8197762e RCX: 0000000080000001 RDX: 0000000000000001 RSI: ffffffff8d9a7514 RDI: ffffffff8be09d60 RBP: ffffffff8de07eb0 R08: ffff8880b863375b R09: 1ffff110170c66eb R10: dffffc0000000000 R11: ffffed10170c66ec R12: ffffffff8fa2daf0 R13: 1ffffffff1bd29d0 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888125bf7000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 000000002889c000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000024 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x73/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:191 [inline] do_idle+0x1be/0x4d0 kernel/sched/idle.c:332 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:430 rest_init+0x2de/0x300 init/main.c:759 start_kernel+0x386/0x3d0 init/main.c:1209 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