syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P2968/2:b..l P5835/1:b..l P5948/1:b..l
rcu: 	(detected by 1, t=10502 jiffies, g=15901, q=440 ncpus=2)
task:syz-executor    state:R  running task     stack:19496 pid:5948  tgid:5948  ppid:5940   task_flags:0x400140 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5258 [inline]
 __schedule+0x150e/0x5070 kernel/sched/core.c:6866
 preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:7050
 preempt_schedule+0xae/0xc0 kernel/sched/core.c:7074
 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
 _raw_spin_unlock_irqrestore+0xfd/0x110 kernel/locking/spinlock.c:194
 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
 __wake_up_common_lock+0x190/0x1f0 kernel/sched/wait.c:127
 sock_def_readable+0x1eb/0x530 net/core/sock.c:3611
 __netlink_sendskb net/netlink/af_netlink.c:1263 [inline]
 netlink_broadcast_deliver net/netlink/af_netlink.c:1399 [inline]
 do_one_broadcast net/netlink/af_netlink.c:1488 [inline]
 netlink_broadcast_filtered+0xc2e/0x1000 net/netlink/af_netlink.c:1533
 netlink_broadcast+0x37/0x50 net/netlink/af_netlink.c:1557
 uevent_net_broadcast_untagged lib/kobject_uevent.c:331 [inline]
 kobject_uevent_net_broadcast+0x378/0x560 lib/kobject_uevent.c:410
 kobject_uevent_env+0x55c/0x9f0 lib/kobject_uevent.c:608
 device_add+0x557/0xb80 drivers/base/core.c:3670
 rfkill_register+0x17a/0x8e0 net/rfkill/core.c:1084
 wiphy_register+0x246a/0x2d20 net/wireless/core.c:1112
 ieee80211_register_hw+0x34a7/0x4110 net/mac80211/main.c:1590
 mac80211_hwsim_new_radio+0x2f76/0x5320 drivers/net/wireless/virtual/mac80211_hwsim.c:5810
 hwsim_new_radio_nl+0xf5b/0x1bd0 drivers/net/wireless/virtual/mac80211_hwsim.c:6504
 genl_family_rcv_msg_doit+0x215/0x300 net/netlink/genetlink.c:1115
 genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline]
 genl_rcv_msg+0x60e/0x790 net/netlink/genetlink.c:1210
 netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2550
 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219
 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+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0bae5915dc
RSP: 002b:00007ffcd54d2300 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f0baf314620 RCX: 00007f0bae5915dc
RDX: 0000000000000024 RSI: 00007f0baf314670 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00007ffcd54d2354 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003
R13: 0000000000000000 R14: 00007f0baf314670 R15: 0000000000000000
 </TASK>
task:udevd           state:R  running task     stack:25784 pid:5835  tgid:5835  ppid:5199   task_flags:0x400140 flags:0x00080800
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5258 [inline]
 __schedule+0x150e/0x5070 kernel/sched/core.c:6866
 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7193
 irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:unwind_next_frame+0x10e/0x23d0 include/linux/rcupdate.h:-1
Code: 46 39 0e 00 75 1f c6 05 7f 46 39 0e 01 48 c7 c7 00 91 88 8b be 65 03 00 00 48 c7 c2 40 91 88 8b e8 a7 86 2a 00 4c 89 6c 24 78 <48> 89 5c 24 70 4d 8d 6e 50 4c 89 e8 48 c1 e8 03 48 89 44 24 38 80
RSP: 0018:ffffc90003fc7218 EFLAGS: 00000202
RAX: 0000000000000001 RBX: ffffffff823d559a RCX: f86b1fd1b8eb9b00
RDX: 000000005a44979c RSI: ffffffff8be252c0 RDI: ffffffff8be25280
RBP: dffffc0000000000 R08: ffffffff81747f85 R09: ffffffff8e341b20
R10: ffffc90003fc7338 R11: ffffffff81ade390 R12: 1ffff920007f8e5d
R13: ffffc90003fc7320 R14: ffffc90003fc72e8 R15: ffffffff81747f85
 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57
 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556
 __call_rcu_common kernel/rcu/tree.c:3119 [inline]
 call_rcu+0x157/0x9c0 kernel/rcu/tree.c:3239
 slab_free_hook mm/slub.c:2504 [inline]
 slab_free mm/slub.c:6670 [inline]
 kmem_cache_free+0x488/0x620 mm/slub.c:6781
 __fput_deferred+0x227/0x390 fs/file_table.c:523
 fput_close+0x113/0x220 fs/file_table.c:585
 path_openat+0x367c/0x3dd0 fs/namei.c:4796
 do_filp_open+0x1fa/0x410 fs/namei.c:4814
 do_sys_openat2+0x121/0x200 fs/open.c:1430
 do_sys_open fs/open.c:1436 [inline]
 __do_sys_openat fs/open.c:1452 [inline]
 __se_sys_openat fs/open.c:1447 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1447
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8d684a7407
RSP: 002b:00007ffd874af200 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f8d68b40880 RCX: 00007f8d684a7407
RDX: 0000000000080000 RSI: 00007ffd874af370 RDI: ffffffffffffff9c
RBP: 0000000000000008 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 000055f3384587f5
R13: 000055f3384587f5 R14: 0000000000000001 R15: 000055f338473140
 </TASK>
task:kworker/u8:10   state:R  running task     stack:23456 pid:2968  tgid:2968  ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: ipv6_addrconf addrconf_dad_work
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5258 [inline]
 __schedule+0x150e/0x5070 kernel/sched/core.c:6866
 preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:7050
 preempt_schedule+0xae/0xc0 kernel/sched/core.c:7074
 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
 __local_bh_enable_ip+0x13e/0x1c0 kernel/softirq.c:457
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 rcu_read_unlock_bh include/linux/rcupdate.h:936 [inline]
 __dev_queue_xmit+0x1955/0x3140 net/core/dev.c:4845
 neigh_output include/net/neighbour.h:556 [inline]
 ip6_finish_output2+0xfb3/0x1480 net/ipv6/ip6_output.c:136
 NF_HOOK_COND include/linux/netfilter.h:307 [inline]
 ip6_output+0x340/0x550 net/ipv6/ip6_output.c:247
 NF_HOOK include/linux/netfilter.h:318 [inline]
 ndisc_send_skb+0xbce/0x1510 net/ipv6/ndisc.c:512
 ndisc_send_ns+0xcb/0x150 net/ipv6/ndisc.c:670
 addrconf_dad_work+0xaae/0x14b0 net/ipv6/addrconf.c:4282
 process_one_work+0x93a/0x15a0 kernel/workqueue.c:3279
 process_scheduled_works kernel/workqueue.c:3362 [inline]
 worker_thread+0x9b0/0xee0 kernel/workqueue.c:3443
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
rcu: rcu_preempt kthread starved for 10660 jiffies! g15901 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:27728 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5258 [inline]
 __schedule+0x150e/0x5070 kernel/sched/core.c:6866
 __schedule_loop kernel/sched/core.c:6948 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6963
 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083
 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
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: 6061 Comm: syz.3.20 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:26 [inline]
RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:109 [inline]
RIP: 0010:lockdep_hardirqs_on_prepare+0x6a/0x290 kernel/locking/lockdep.c:4391
Code: 25 11 85 c0 0f 85 7c 01 00 00 65 8b 05 67 3f 25 11 85 c0 0f 85 6d 01 00 00 83 3d 40 51 30 18 00 75 3e 48 c7 04 24 00 00 00 00 <9c> 8f 04 24 f7 04 24 00 02 00 00 0f 85 8c 01 00 00 83 3d 1e 51 30
RSP: 0018:ffffc90002fe7ea8 EFLAGS: 00000046
RAX: 0000000000000000 RBX: ffffc90002fe7ee0 RCX: 4ba8cb5ed4453000
RDX: 0000000000000000 RSI: ffffffff8be252c0 RDI: ffffffff8be25280
RBP: ffffc90002fe7f38 R08: ffffffff8fc3ce77 R09: 1ffffffff1f879ce
R10: dffffc0000000000 R11: fffffbfff1f879cf R12: 0000000000000000
R13: 000000000000000f R14: ffffc90002fe7f48 R15: ffff8880357adb80
FS:  00007f640af906c0(0000) GS:ffff8881259e6000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002000000001c0 CR3: 0000000011b1c000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 exit_to_user_mode include/linux/irq-entry-common.h:298 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:196 [inline]
 do_syscall_64+0x1de/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f640a1b7e80
Code: 83 c0 16 83 e0 f7 74 12 50 48 8d 3d 8a 54 08 00 e8 05 8f f8 ff 0f 1f 44 00 00 c3 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 <83> ff 21 74 0b c3 66 2e 0f 1f 84 00 00 00 00 00 55 53 48 89 f3 48
RSP: 002b:00007f640af8fb38 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00007f640a3e5fa8 RCX: 00007f640a18f749
RDX: 00007f640af8fb40 RSI: 00007f640af8fc70 RDI: 0000000000000021
RBP: 00007f640a3e5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f640a3e6038 R14: 00007fff185d2a40 R15: 00007fff185d2b28
 </TASK>