syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P4330/1:b..l
	(detected by 1, t=10502 jiffies, g=7029, q=508)
task:syz-executor    state:R  running task     stack:21840 pid: 4330 ppid:  4327 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
 preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6799
 irqentry_exit+0x63/0x70 kernel/entry/common.c:432
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:__thunk_restore+0xc/0x10 arch/x86/entry/thunk_64.S:48
Code: 7a 91 c4 08 eb 18 55 48 89 e5 57 56 52 51 50 41 50 41 51 41 52 41 53 e8 02 93 c4 08 eb 00 41 5b 41 5a 41 59 41 58 58 59 5a 5e <5f> 5d c3 00 81 fe c0 01 00 00 0f 87 c4 d1 ff ff 89 f0 ff 24 c5 c0
RSP: 0018:ffffc900031ee208 EFLAGS: 00000246
RAX: ffffffff816047b4 RBX: 0000000000000049 RCX: ffff88802a5c9dc0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88802a5c9dc0
RBP: ffffc900031ee210 R08: ffffc900031ede87 R09: 1ffff9200063dbd0
R10: dffffc0000000000 R11: fffff5200063dbd1 R12: ffffc900031ee2a0
R13: 0000000000000000 R14: 0000000000000000 R15: ffffffff8b1f6400
 vprintk_emit+0x149/0x150 kernel/printk/printk.c:2275
 dev_vprintk_emit+0x2e1/0x380 drivers/base/core.c:4638
 dev_printk_emit+0xeb/0x140 drivers/base/core.c:4649
 __netdev_printk+0x2ef/0x3d0 net/core/dev.c:11530
 netdev_info+0x11b/0x170 net/core/dev.c:11585
 nsim_udp_tunnel_set_port+0x293/0x430 drivers/net/netdevsim/udp_tunnels.c:34
 udp_tunnel_nic_device_sync_one net/ipv4/udp_tunnel_nic.c:-1 [inline]
 udp_tunnel_nic_device_sync_by_port net/ipv4/udp_tunnel_nic.c:246 [inline]
 __udp_tunnel_nic_device_sync+0x9db/0x12e0 net/ipv4/udp_tunnel_nic.c:289
 udp_tunnel_nic_device_sync net/ipv4/udp_tunnel_nic.c:312 [inline]
 __udp_tunnel_nic_add_port+0xb83/0xe80 net/ipv4/udp_tunnel_nic.c:531
 udp_tunnel_nic_add_port include/net/udp_tunnel.h:336 [inline]
 udp_tunnel_notify_add_rx_port+0x266/0x3a0 net/ipv4/udp_tunnel_core.c:130
 geneve_socket_create drivers/net/geneve.c:614 [inline]
 geneve_sock_add+0x515/0x960 drivers/net/geneve.c:689
 geneve_open+0xce/0x140 drivers/net/geneve.c:731
 __dev_open+0x2bf/0x430 net/core/dev.c:1550
 __dev_change_flags+0x20d/0x6a0 net/core/dev.c:8879
 dev_change_flags+0x82/0x1a0 net/core/dev.c:8950
 do_setlink+0xcdb/0x3d60 net/core/rtnetlink.c:2784
 __rtnl_newlink net/core/rtnetlink.c:3455 [inline]
 rtnl_newlink+0x1658/0x1a50 net/core/rtnetlink.c:3577
 rtnetlink_rcv_msg+0x844/0xf30 net/core/rtnetlink.c:5687
 netlink_rcv_skb+0x1f5/0x440 net/netlink/af_netlink.c:2507
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x774/0x920 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x8ba/0xbe0 net/netlink/af_netlink.c:1918
 sock_sendmsg_nosec net/socket.c:706 [inline]
 __sock_sendmsg net/socket.c:718 [inline]
 __sys_sendto+0x46d/0x620 net/socket.c:2072
 __do_sys_sendto net/socket.c:2084 [inline]
 __se_sys_sendto net/socket.c:2080 [inline]
 __x64_sys_sendto+0xda/0xf0 net/socket.c:2080
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fe67421860e
RSP: 002b:00007ffd4226bef8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 000055555e5e6500 RCX: 00007fe67421860e
RDX: 000000000000002c RSI: 00007fe674fff670 RDI: 0000000000000003
RBP: 0000000000000001 R08: 00007ffd4226bf74 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
R13: 0000000000000000 R14: 00007fe674fff670 R15: 0000000000000000
 </TASK>
rcu: rcu_preempt kthread starved for 10563 jiffies! g7029 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:27800 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2117
 rcu_gp_fqs_loop+0x2be/0x11d0 kernel/rcu/tree.c:1972
 rcu_gp_kthread+0x9b/0x370 kernel/rcu/tree.c:2145
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </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 PID: 4418 Comm: syz.1.36 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:29 [inline]
RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:70 [inline]
RIP: 0010:arch_local_irq_save arch/x86/include/asm/irqflags.h:106 [inline]
RIP: 0010:lock_is_held_type+0x61/0x190 kernel/locking/lockdep.c:5662
Code: 0f 85 f4 00 00 00 65 48 8b 1d 6b a3 45 76 83 bb ec 0a 00 00 00 0f 85 df 00 00 00 41 89 f7 49 89 fe 48 c7 04 24 00 00 00 00 9c <8f> 04 24 4c 8b 2c 24 fa 48 c7 c7 00 36 2b 8a e8 4b 0e 00 00 65 ff
RSP: 0018:ffffc900034af6b0 EFLAGS: 00000046
RAX: 0000000000000000 RBX: ffff88801e751dc0 RCX: 313d526a43df3c00
RDX: 0000000000000009 RSI: 00000000ffffffff RDI: ffffffff8c31ebe0
RBP: 00000000ffffffff R08: ffff88801e751dc7 R09: 1ffff11003cea3b8
R10: dffffc0000000000 R11: ffffed1003cea3b9 R12: ffff88807d028000
R13: ffff88802becc910 R14: ffffffff8c31ebe0 R15: 00000000ffffffff
FS:  00007f93dd7866c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000058 CR3: 000000007b6a5000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 lock_is_held include/linux/lockdep.h:287 [inline]
 rcu_read_lock_sched_held+0x86/0x110 kernel/rcu/update.c:125
 task_css_set include/linux/cgroup.h:483 [inline]
 task_dfl_cgroup include/linux/cgroup.h:552 [inline]
 cgroup_account_cputime include/linux/cgroup.h:796 [inline]
 update_curr_rt+0x265/0x930 kernel/sched/rt.c:1031
 dequeue_task_rt+0x21/0x1b0 kernel/sched/rt.c:1408
 dequeue_task kernel/sched/core.c:2016 [inline]
 deactivate_task kernel/sched/core.c:2033 [inline]
 __schedule+0x6b6/0x43c0 kernel/sched/core.c:6349
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 freezable_schedule include/linux/freezer.h:172 [inline]
 futex_wait_queue_me+0x22d/0x440 kernel/futex/core.c:2863
 futex_wait+0x256/0x680 kernel/futex/core.c:2964
 do_futex+0xdb2/0x12b0 kernel/futex/core.c:3983
 __do_sys_futex kernel/futex/core.c:4060 [inline]
 __se_sys_futex+0x389/0x420 kernel/futex/core.c:4041
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f93de124dd9
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:00007f93dd7860e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 00007f93de39dfa8 RCX: 00007f93de124dd9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f93de39dfa8
RBP: 00007f93de39dfa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f93de39e038 R14: 00007ffc0a9b28e0 R15: 00007ffc0a9b29c8
 </TASK>
sched: RT throttling activated