rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6636/1:b..l
rcu: (detected by 0, t=10503 jiffies, g=17229, q=556 ncpus=2)
task:syz-executor state:R running task stack:21736 pid:6636 ppid:6634 flags:0x00004002
Call Trace:
context_switch kernel/sched/core.c:5380 [inline]
__schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6866
preempt_schedule+0xab/0xc0 kernel/sched/core.c:6890
preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45
vprintk_emit+0x578/0x600 kernel/printk/printk.c:2342
dev_vprintk_emit+0x338/0x3e0 drivers/base/core.c:4953
dev_printk_emit+0xe1/0x130 drivers/base/core.c:4964
__netdev_printk+0x3bf/0x4a0 net/core/dev.c:11482
netdev_info+0x10b/0x160 net/core/dev.c:11537
nsim_udp_tunnel_set_port+0x297/0x440 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+0xa70/0x1370 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+0xaf8/0xdb0 net/ipv4/udp_tunnel_nic.c:531
udp_tunnel_nic_add_port include/net/udp_tunnel.h:333 [inline]
udp_tunnel_notify_add_rx_port+0x28e/0x3e0 net/ipv4/udp_tunnel_core.c:127
geneve_socket_create drivers/net/geneve.c:614 [inline]
geneve_sock_add+0x55e/0x910 drivers/net/geneve.c:689
geneve_open+0xd2/0x140 drivers/net/geneve.c:731
__dev_open+0x2bc/0x430 net/core/dev.c:1506
__dev_change_flags+0x20e/0x6a0 net/core/dev.c:8685
dev_change_flags+0x88/0x1a0 net/core/dev.c:8757
do_setlink+0xc74/0x3fb0 net/core/rtnetlink.c:2905
__rtnl_newlink net/core/rtnetlink.c:3703 [inline]
rtnl_newlink+0x175b/0x2020 net/core/rtnetlink.c:3750
rtnetlink_rcv_msg+0x7c7/0xf10 net/core/rtnetlink.c:6475
netlink_rcv_skb+0x216/0x480 net/netlink/af_netlink.c:2545
netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
netlink_unicast+0x751/0x8d0 net/netlink/af_netlink.c:1346
netlink_sendmsg+0x8c1/0xbe0 net/netlink/af_netlink.c:1894
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg net/socket.c:745 [inline]
__sys_sendto+0x46a/0x620 net/socket.c:2201
__do_sys_sendto net/socket.c:2213 [inline]
__se_sys_sendto net/socket.c:2209 [inline]
__x64_sys_sendto+0xde/0xf0 net/socket.c:2209
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fb0ec390a7c
RSP: 002b:00007ffe987154f0 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007fb0ed0f4620 RCX: 00007fb0ec390a7c
RDX: 000000000000002c RSI: 00007fb0ed0f4670 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00007ffe98715544 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003
R13: 0000000000000000 R14: 00007fb0ed0f4670 R15: 0000000000000000
rcu: rcu_preempt kthread starved for 10565 jiffies! g17229 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:27560 pid:17 ppid:2 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5380 [inline]
__schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
schedule+0xbd/0x170 kernel/sched/core.c:6773
schedule_timeout+0x160/0x280 kernel/time/timer.c:2167
rcu_gp_fqs_loop+0x302/0x1560 kernel/rcu/tree.c:1667
rcu_gp_kthread+0x99/0x380 kernel/rcu/tree.c:1866
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 6883 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:check_kcov_mode kernel/kcov.c:193 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x36/0x60 kernel/kcov.c:216
Code: 50 2a 7e 7e 65 8b 15 51 2a 7e 7e 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 1c 16 00 00 00 74 2c 8b 91 f8 15 00 00 <83> fa 02 75 21 48 8b 91 00 16 00 00 48 8b 32 48 8d 7e 01 8b 89 fc
RSP: 0018:ffffc90003827d38 EFLAGS: 00000246
RAX: ffffffff81311f4c RBX: ffff88802ad39940 RCX: ffff88802ad38000
RDX: 0000000000000000 RSI: ffffffff8aa58a20 RDI: ffffffff8afc70c0
RBP: 0000000000000000 R08: ffffffff8e4a912f R09: 1ffffffff1c95225
R10: dffffc0000000000 R11: fffffbfff1c95226 R12: ffff88802ad39940
R13: dffffc0000000000 R14: ffff88802ad39940 R15: ffffffff813113aa
FS: 00007ff4df0676c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000058 CR3: 000000005ed33000 CR4: 00000000003506e0
Call Trace:
arch_static_branch arch/x86/include/asm/jump_label.h:27 [inline]
static_key_false include/linux/jump_label.h:207 [inline]
trace_x86_fpu_regs_activated arch/x86/include/asm/trace/fpu.h:57 [inline]
fpregs_activate+0x2c/0x1b0 arch/x86/kernel/fpu/context.h:50
fpregs_mark_activate arch/x86/kernel/fpu/core.c:831 [inline]
fpu__clear_user_states+0x177/0x270 arch/x86/kernel/fpu/core.c:770
handle_signal arch/x86/kernel/signal.c:283 [inline]
arch_do_signal_or_restart+0x477/0x780 arch/x86/kernel/signal.c:312
exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:87
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7ff4de1b7320
Code: 83 c0 16 83 e0 f7 74 12 50 48 8d 3d 4a 3e 08 00 e8 f5 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:00007ff4df066b38 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00007ff4de3c5fa8 RCX: 00007ff4de18ebe9
RDX: 00007ff4df066b40 RSI: 00007ff4df066c70 RDI: 0000000000000021
RBP: 00007ff4de3c5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff4de3c6038 R14: 00007fff676cdc70 R15: 00007fff676cdd58
sched: RT throttling activated