rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4336/1:b..l P3638/1:b..l
(detected by 1, t=10502 jiffies, g=11601, q=17 ncpus=2)
task:udevd state:R running task stack:24912 pid:3638 ppid:1 flags:0x00004002
Call Trace:
context_switch kernel/sched/core.c:5245 [inline]
__schedule+0x11d1/0x40e0 kernel/sched/core.c:6562
preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6731
preempt_schedule+0xbc/0xd0 kernel/sched/core.c:6755
preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
_raw_spin_unlock_irqrestore+0x10d/0x120 kernel/locking/spinlock.c:194
spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
__wake_up_common_lock kernel/sched/wait.c:140 [inline]
__wake_up_sync_key+0x128/0x190 kernel/sched/wait.c:208
sock_def_readable+0x15b/0x280 net/core/sock.c:3316
__netlink_sendskb net/netlink/af_netlink.c:1264 [inline]
netlink_sendskb+0x97/0x130 net/netlink/af_netlink.c:1270
netlink_sendmsg+0x8ad/0xbd0 net/netlink/af_netlink.c:1872
sock_sendmsg_nosec net/socket.c:718 [inline]
__sock_sendmsg net/socket.c:730 [inline]
____sys_sendmsg+0x5be/0x970 net/socket.c:2518
___sys_sendmsg+0x2a2/0x360 net/socket.c:2572
__sys_sendmsg net/socket.c:2601 [inline]
__do_sys_sendmsg net/socket.c:2610 [inline]
__se_sys_sendmsg+0x1bb/0x2a0 net/socket.c:2608
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f0ff68a7407
RSP: 002b:00007fffabb4d970 EFLAGS: 00000202 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f0ff7030880 RCX: 00007f0ff68a7407
RDX: 0000000000000000 RSI: 00007fffabb4d9d0 RDI: 0000000000000004
RBP: 0000564d460edb30 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 00000000000000b3
R13: 0000564d460db9e0 R14: 0000000000000000 R15: 0000000000000000
task:kworker/u4:7 state:R running task stack:25200 pid:4336 ppid:2 flags:0x00004000
Workqueue: events_unbound bpf_map_free_deferred
Call Trace:
context_switch kernel/sched/core.c:5245 [inline]
__schedule+0x11d1/0x40e0 kernel/sched/core.c:6562
preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6874
irqentry_exit+0x63/0x70 kernel/entry/common.c:439
asm_sysvec_reschedule_ipi+0x16/0x20 arch/x86/include/asm/idtentry.h:696
RIP: 0010:should_resched arch/x86/include/asm/preempt.h:-1 [inline]
RIP: 0010:unwind_next_frame+0x1887/0x20b0 arch/x86/kernel/unwind_orc.c:629
Code: 41 d2 0c 00 75 3e c6 05 0a 41 d2 0c 01 48 c7 c7 60 84 89 8a e9 9d fa ff ff bf 01 00 00 00 e8 40 b9 1f 00 65 8b 0d 91 3c c9 7e 01 85 c9 75 75 e8 de 50 c7 ff eb 6e 80 3d d8 40 d2 0c 00 0f 84
RSP: 0018:ffffc900044e77d0 EFLAGS: 00000297
RAX: 0000000080000001 RBX: ffffc900044e78a8 RCX: 0000000080000000
RDX: ffffc900044e7801 RSI: dffffc0000000000 RDI: 00000000ffffffff
RBP: ffffffff8e9fe6c2 R08: ffffc900044e7dc0 R09: ffffc900044e78f8
R10: dffffc0000000000 R11: fffff5200089cf21 R12: ffffc900044e0000
R13: dffffc0000000000 R14: ffffc900044e78b8 R15: ffffc900044e7dd0
arch_stack_walk+0x10c/0x140 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0xa6/0xf0 kernel/stacktrace.c:122
save_stack+0x121/0x230 mm/page_owner.c:127
__reset_page_owner+0x51/0x1a0 mm/page_owner.c:148
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1486 [inline]
free_pcp_prepare mm/page_alloc.c:1536 [inline]
free_unref_page_prepare+0x8b4/0x9a0 mm/page_alloc.c:3413
free_unref_page+0x2e/0x3f0 mm/page_alloc.c:3508
bpf_ringbuf_free kernel/bpf/ringbuf.c:231 [inline]
ringbuf_map_free+0xc5/0x120 kernel/bpf/ringbuf.c:240
process_one_work+0x8a2/0x1160 kernel/workqueue.c:2292
worker_thread+0xaa2/0x1270 kernel/workqueue.c:2439
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
rcu: rcu_preempt kthread starved for 10558 jiffies! g11601 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:27760 pid:16 ppid:2 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5245 [inline]
__schedule+0x11d1/0x40e0 kernel/sched/core.c:6562
schedule+0xb9/0x180 kernel/sched/core.c:6638
schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2168
rcu_gp_fqs_loop+0x303/0x1340 kernel/rcu/tree.c:1706
rcu_gp_kthread+0x99/0x3b0 kernel/rcu/tree.c:1905
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
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: 4733 Comm: syz.1.109 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:mark_lock+0x0/0x320 kernel/locking/lockdep.c:4589
Code: 38 c1 7c 90 48 c7 c7 a8 13 20 8e e8 4a 88 6e 00 4c 89 f7 41 89 d9 e9 79 ff ff ff 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 <55> 41 57 41 56 41 55 41 54 53 50 89 d5 49 89 f6 48 89 fb 49 bd 00
RSP: 0018:ffffc90000007878 EFLAGS: 00000046
RAX: 0000000000000003 RBX: 0000000000000003 RCX: 0000000000000002
RDX: 0000000000000008 RSI: ffff888029af46d8 RDI: ffff888029af3b80
RBP: ffffc90000007ad0 R08: dffffc0000000000 R09: 1ffffffff215ee48
R10: dffffc0000000000 R11: fffffbfff215ee49 R12: ffff888029af3b80
R13: 0000000000000002 R14: ffff888029af46d8 R15: ffff888029af46f8
FS: 00007f203d6256c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000058 CR3: 0000000028894000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
mark_usage kernel/locking/lockdep.c:4549 [inline]
__lock_acquire+0xd7e/0x7d10 kernel/locking/lockdep.c:5003
lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5662
rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
rcu_read_lock include/linux/rcupdate.h:791 [inline]
__lock_task_sighand+0x42/0x2d0 kernel/signal.c:1394
lock_task_sighand include/linux/sched/signal.h:745 [inline]
send_sigqueue+0x159/0x610 kernel/signal.c:1979
posix_timer_event kernel/time/posix-timers.c:360 [inline]
posix_timer_fn+0x16a/0x3d0 kernel/time/posix-timers.c:386
__run_hrtimer kernel/time/hrtimer.c:1747 [inline]
__hrtimer_run_queues+0x54a/0xd50 kernel/time/hrtimer.c:1811
hrtimer_interrupt+0x3c5/0x9c0 kernel/time/hrtimer.c:1873
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1107 [inline]
__sysvec_apic_timer_interrupt+0x153/0x5a0 arch/x86/kernel/apic/apic.c:1124
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1118
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:lock_acquire+0x225/0x4a0 kernel/locking/lockdep.c:5666
Code: f7 84 24 80 00 00 00 00 02 00 00 43 c6 44 3d 04 f8 0f 85 f0 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 44 3d 00 00 00 00 00 43 c7 44 3d 08 00 00 00 00 65 48 8b 04
RSP: 0018:ffffc90005737940 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 26e2232e2c937500
RDX: 0000000000000000 RSI: ffffffff8a8c2220 RDI: ffffffff8adf0d20
RBP: ffffc90005737a50 R08: dffffc0000000000 R09: 1ffffffff215ee4e
R10: dffffc0000000000 R11: fffffbfff215ee4f R12: 0000000000000000
R13: 1ffff92000ae6f34 R14: 0000000000000246 R15: dffffc0000000000
__might_fault+0xc2/0x120 mm/memory.c:5850
__clear_user arch/x86/include/asm/uaccess_64.h:96 [inline]
copy_fpstate_to_sigframe+0x1bc/0xd50 arch/x86/kernel/fpu/signal.c:216
get_sigframe arch/x86/kernel/signal.c:297 [inline]
__setup_rt_frame arch/x86/kernel/signal.c:472 [inline]
setup_rt_frame arch/x86/kernel/signal.c:784 [inline]
handle_signal arch/x86/kernel/signal.c:828 [inline]
arch_do_signal_or_restart+0x69f/0x1350 arch/x86/kernel/signal.c:873
exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f203c79c797
Code: 83 c8 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
RSP: 002b:00007f203d625028 EFLAGS: 00000246
RAX: 0000000000000049 RBX: 00007f203ca15fa0 RCX: 00007f203c79c799
RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000005
RBP: 00007f203c832c99 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f203ca16038 R14: 00007f203ca15fa0 R15: 00007ffd4b54ead8
sched: RT throttling activated