rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6349/1:b..l P5184/1:b..l
rcu: (detected by 1, t=10502 jiffies, g=15833, q=768 ncpus=2)
task:klogd state:R running task stack:24120 pid:5184 tgid:5184 ppid:1 task_flags:0x400100 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5257 [inline]
__schedule+0x14bc/0x5000 kernel/sched/core.c:6864
preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:7048
preempt_schedule+0xae/0xc0 kernel/sched/core.c:7072
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
unix_dgram_sendmsg+0xdfb/0x1840 net/unix/af_unix.c:2286
sock_sendmsg_nosec+0x18f/0x1d0 net/socket.c:728
__sock_sendmsg net/socket.c:743 [inline]
__sys_sendto+0x3ce/0x540 net/socket.c:2212
__do_sys_sendto net/socket.c:2219 [inline]
__se_sys_sendto net/socket.c:2215 [inline]
__x64_sys_sendto+0xde/0x100 net/socket.c:2215
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: 0033:0x7f8de6ce7407
RSP: 002b:00007fff46c80130 EFLAGS: 00000202 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f8de6b97c80 RCX: 00007f8de6ce7407
RDX: 000000000000007a RSI: 00007fff46c80270 RDI: 0000000000000003
RBP: 00007fff46c806a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000004000 R11: 0000000000000202 R12: 00007fff46c806b8
R13: 00007fff46c80270 R14: 000000000000005f R15: 00007fff46c80270
task:syz-executor state:R running task stack:22256 pid:6349 tgid:6349 ppid:6337 task_flags:0x400140 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5257 [inline]
__schedule+0x14bc/0x5000 kernel/sched/core.c:6864
preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7191
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:lock_acquire+0x16c/0x340 kernel/locking/lockdep.c:5872
Code: 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 74 97 de 10 <48> 3b 44 24 58 0f 85 e5 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e
RSP: 0018:ffffc9000bcf6ba8 EFLAGS: 00000206
RAX: 20964b45a730b300 RBX: 0000000000000000 RCX: 20964b45a730b300
RDX: 00000000b815b83c RSI: ffffffff8d969d83 RDI: ffffffff8bc018e0
RBP: ffffffff81ac1877 R08: ffffffff81ac1877 R09: ffffffff8df419e0
R10: 0000000000000007 R11: 0000000000000000 R12: 0000000000000002
R13: ffffffff8df419e0 R14: 0000000000000000 R15: 0000000000000246
rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
rcu_read_lock include/linux/rcupdate.h:867 [inline]
class_rcu_constructor include/linux/rcupdate.h:1195 [inline]
is_module_address+0x33/0xf0 kernel/module/main.c:3811
ensure_safe_net_sysctl net/sysctl_net.c:145 [inline]
register_net_sysctl_sz+0xe6/0x450 net/sysctl_net.c:169
__addrconf_sysctl_register+0x328/0x4c0 net/ipv6/addrconf.c:7323
addrconf_sysctl_register+0x168/0x1c0 net/ipv6/addrconf.c:7371
ipv6_add_dev+0xd44/0x13c0 net/ipv6/addrconf.c:460
addrconf_notify+0x771/0x1050 net/ipv6/addrconf.c:3650
notifier_call_chain+0x19d/0x3a0 kernel/notifier.c:85
call_netdevice_notifiers_extack net/core/dev.c:2269 [inline]
call_netdevice_notifiers net/core/dev.c:2283 [inline]
register_netdevice+0x15bd/0x1a70 net/core/dev.c:11430
br_dev_newlink+0x6a/0x140 net/bridge/br_netlink.c:1565
rtnl_newlink_create+0x310/0xb00 net/core/rtnetlink.c:3840
__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:728
__sock_sendmsg net/socket.c:743 [inline]
__sys_sendto+0x3ce/0x540 net/socket.c:2212
__do_sys_sendto net/socket.c:2219 [inline]
__se_sys_sendto net/socket.c:2215 [inline]
__x64_sys_sendto+0xde/0x100 net/socket.c:2215
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: 0033:0x7f76075915dc
RSP: 002b:00007ffeed1cd4f0 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f7608314620 RCX: 00007f76075915dc
RDX: 000000000000003c RSI: 00007f7608314670 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00007ffeed1cd544 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003
R13: 0000000000000000 R14: 00007f7608314670 R15: 0000000000000000
rcu: rcu_preempt kthread starved for 10577 jiffies! g15833 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:27736 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5257 [inline]
__schedule+0x14bc/0x5000 kernel/sched/core.c:6864
__schedule_loop kernel/sched/core.c:6946 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6961
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
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 UID: 0 PID: 6398 Comm: syz.0.105 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:syscall_enter_from_user_mode_work include/linux/entry-common.h:77 [inline]
RIP: 0010:syscall_enter_from_user_mode include/linux/entry-common.h:109 [inline]
RIP: 0010:do_syscall_64+0xc3/0xf80 arch/x86/entry/syscall_64.c:90
Code: 00 48 8b 7d 08 48 89 7b 18 e8 09 82 00 00 0f 1f 44 00 00 0f 1f 44 00 00 90 e8 49 a8 70 f6 90 90 e8 f2 a7 70 f6 fb 49 8b 57 08 c2 3f 74 0e 4c 89 f7 4c 89 ee e8 9d aa 52 f6 49 89 c4 90 90 41
RSP: 0018:ffffc9000c007ee0 EFLAGS: 00000282
RAX: 78b1ae0b427fd900 RBX: ffffc9000c007ee0 RCX: 78b1ae0b427fd900
RDX: 0000000000000000 RSI: ffffffff8d783537 RDI: ffffffff8bc018e0
RBP: ffffc9000c007f38 R08: ffffffff8f813377 R09: 1ffffffff1f0266e
R10: dffffc0000000000 R11: fffffbfff1f0266f R12: 000000000000000f
R13: 000000000000000f R14: ffffc9000c007f48 R15: ffff888030db3d00
FS: 00007fec19bf66c0(0000) GS:ffff888125f4f000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c2a6213 CR3: 000000007ce4e000 CR4: 00000000003526f0
Call Trace:
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fec1b92b829
Code: 64 c7 00 16 00 00 00 b8 ff ff ff ff c3 0f 1f 40 00 90 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 c7 c0 0f 00 00 00 0f 05 <0f> 1f 80 00 00 00 00 48 81 ec 48 01 00 00 49 89 d0 64 48 8b 04 25
RSP: 002b:00007fec19bf5b40 EFLAGS: 00000206 ORIG_RAX: 000000000000000f
RAX: ffffffffffffffda RBX: 00007fec1bbe6098 RCX: 00007fec1b92b829
RDX: 00007fec19bf5b40 RSI: 00007fec19bf5c70 RDI: 0000000000000021
RBP: 00007fec1bbe6090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007fec1bbe6128 R14: 00007ffec0114560 R15: 00007ffec0114648