rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 1-....: (9821 ticks this GP) idle=90ec/1/0x4000000000000000 softirq=24996/24997 fqs=1582
rcu: hardirqs softirqs csw/system
rcu: number: 1228943 0 0
rcu: cputime: 14964 35065 46 ==> 50060(ms)
rcu: (t=10504 jiffies g=29129 q=1708 ncpus=2)
rcu: rcu_preempt kthread timer wakeup didn't happen for 385 jiffies! g29129 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: Possible timer handling issue on cpu=0 timer-softirq=18624
rcu: rcu_preempt kthread starved for 388 jiffies! g29129 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27656 pid:17 ppid:2 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5381 [inline]
__schedule+0x1553/0x45a0 kernel/sched/core.c:6700
schedule+0xbd/0x170 kernel/sched/core.c:6774
schedule_timeout+0x188/0x2d0 kernel/time/timer.c:2168
rcu_gp_fqs_loop+0x313/0x1590 kernel/rcu/tree.c:1667
rcu_gp_kthread+0x9d/0x3b0 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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:pv_native_safe_halt+0xf/0x10 arch/x86/kernel/paravirt.c:148
Code: 39 21 02 c3 cc cc cc cc cc cc cc f3 0f 1e fa 0f 0b 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 66 90 0f 00 2d e3 f3 41 00 fb f4 66 0f 1f 00 55 41 57 41 56 41 54 53 50 8b 2f eb 2e 41 89 de 80
RSP: 0018:ffffc900000078d8 EFLAGS: 00000246
RAX: ffffffff813aa578 RBX: 0000000000000003 RCX: ffffffff8ce93440
RDX: 0000000000000100 RSI: ffffffff8acac9e0 RDI: ffffffff8b1c8e60
RBP: ffffc900000079b0 R08: ffffffff911c55c7 R09: 1ffffffff2238ab8
R10: dffffc0000000000 R11: fffffbfff2238ab9 R12: dffffc0000000000
R13: 0000000000000200 R14: 0000000000000003 R15: 1ffff92000000f20
FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055d8c10d9a38 CR3: 000000000cf32000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
arch_safe_halt arch/x86/include/asm/paravirt.h:108 [inline]
kvm_wait+0x23d/0x2a0 arch/x86/kernel/kvm.c:1058
pv_wait arch/x86/include/asm/paravirt.h:598 [inline]
pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:470 [inline]
__pv_queued_spin_lock_slowpath+0x61a/0x9d0 kernel/locking/qspinlock.c:511
pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:586 [inline]
queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:51 [inline]
queued_spin_lock include/asm-generic/qspinlock.h:114 [inline]
do_raw_spin_lock+0x23e/0x2c0 kernel/locking/spinlock_debug.c:115
spin_lock include/linux/spinlock.h:351 [inline]
tcp_write_timer+0x2d/0x280 net/ipv4/tcp_timer.c:707
call_timer_fn+0x189/0x540 kernel/time/timer.c:1701
expire_timers kernel/time/timer.c:1752 [inline]
__run_timers+0x542/0x800 kernel/time/timer.c:2023
run_timer_softirq+0x67/0xf0 kernel/time/timer.c:2036
handle_softirqs+0x280/0x820 kernel/softirq.c:578
__do_softirq kernel/softirq.c:612 [inline]
invoke_softirq kernel/softirq.c:452 [inline]
__irq_exit_rcu+0xd3/0x190 kernel/softirq.c:661
irq_exit_rcu+0x9/0x20 kernel/softirq.c:673
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:pv_native_safe_halt+0xf/0x10 arch/x86/kernel/paravirt.c:148
Code: 39 21 02 c3 cc cc cc cc cc cc cc f3 0f 1e fa 0f 0b 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 66 90 0f 00 2d e3 f3 41 00 fb f4 66 0f 1f 00 55 41 57 41 56 41 54 53 50 8b 2f eb 2e 41 89 de 80
RSP: 0018:ffffffff8ce07d80 EFLAGS: 000002c6
RAX: 76e74b4782ffc900 RBX: ffffffff8162aa0d RCX: 76e74b4782ffc900
RDX: 0000000000000001 RSI: ffffffff8acac9e0 RDI: ffffffff8b1c8e60
RBP: ffffffff8ce07eb8 R08: ffff8880b8e36b2b R09: 1ffff110171c6d65
R10: dffffc0000000000 R11: ffffed10171c6d66 R12: 1ffffffff19c0fbc
R13: dffffc0000000000 R14: 1ffffffff19d2688 R15: 0000000000000000
arch_safe_halt arch/x86/include/asm/paravirt.h:108 [inline]
default_idle+0x13/0x20 arch/x86/kernel/process.c:753
default_idle_call+0x6c/0xa0 kernel/sched/idle.c:97
cpuidle_idle_call kernel/sched/idle.c:178 [inline]
do_idle+0x33d/0x590 kernel/sched/idle.c:302
cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:401
rest_init+0x2e2/0x300 init/main.c:744
arch_call_rest_init+0xe/0x10 init/main.c:841
start_kernel+0x459/0x4e0 init/main.c:1086
x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:555
x86_64_start_kernel+0x60/0x60 arch/x86/kernel/head64.c:536
secondary_startup_64_no_verify+0x179/0x17b
CPU: 1 PID: 9099 Comm: syz.0.850 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:__debug_check_no_obj_freed lib/debugobjects.c:-1 [inline]
RIP: 0010:debug_check_no_obj_freed+0xe8/0x540 lib/debugobjects.c:1020
Code: 5e 41 5f 5d e9 a9 28 26 fd 48 83 c4 58 5b 41 5c 41 5d 41 5e 41 5f 5d c3 49 c1 ef 0c 31 c0 4c 89 64 24 48 4c 89 6c 24 18 eb 17 <48> 8b 44 24 40 01 d8 49 81 c6 00 10 00 00 49 ff cf 0f 84 4f ff ff
RSP: 0018:ffffc900001ef0d0 EFLAGS: 00000293
RAX: 7cd81150a7341e00 RBX: 0000000000000000 RCX: 0000000000000300
RDX: dffffc0000000000 RSI: ffffffff8acac9e0 RDI: 00000000ffffffff
RBP: 0000000000000000 R08: ffffffff911c55c7 R09: 1ffffffff2238ab8
R10: dffffc0000000000 R11: fffffbfff2238ab9 R12: ffff88802622f9b0
R13: ffff88802622f8c0 R14: ffff88802622f000 R15: 0000000000000001
FS: 00007f18634ab6c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000100000000 CR3: 00000000759c5000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
slab_free_hook mm/slub.c:1786 [inline]
slab_free_freelist_hook+0xd2/0x1a0 mm/slub.c:1837
slab_free mm/slub.c:3830 [inline]
kmem_cache_free+0xf8/0x270 mm/slub.c:3852
dev_kfree_skb_any_reason+0x120/0x130 net/core/dev.c:3241
free_old_xmit_skbs+0x11a/0x3d0 drivers/net/virtio_net.c:780
start_xmit+0x168/0x14a0 drivers/net/virtio_net.c:2420
__netdev_start_xmit include/linux/netdevice.h:4943 [inline]
netdev_start_xmit include/linux/netdevice.h:4957 [inline]
xmit_one net/core/dev.c:3644 [inline]
dev_hard_start_xmit+0x246/0x740 net/core/dev.c:3660
sch_direct_xmit+0x25e/0x4c0 net/sched/sch_generic.c:345
__dev_xmit_skb net/core/dev.c:3881 [inline]
__dev_queue_xmit+0x165d/0x3660 net/core/dev.c:4416
neigh_output include/net/neighbour.h:543 [inline]
ip_finish_output2+0xd3a/0x11e0 net/ipv4/ip_output.c:235
NF_HOOK_COND include/linux/netfilter.h:293 [inline]
ip_output+0x2a1/0x3b0 net/ipv4/ip_output.c:436
dst_output include/net/dst.h:467 [inline]
ip_local_out net/ipv4/ip_output.c:129 [inline]
__ip_queue_xmit+0x1049/0x1950 net/ipv4/ip_output.c:540
__tcp_transmit_skb+0x1d6b/0x33f0 net/ipv4/tcp_output.c:1425
tcp_transmit_skb net/ipv4/tcp_output.c:1443 [inline]
tcp_write_xmit+0x174c/0x62e0 net/ipv4/tcp_output.c:2781
__tcp_push_pending_frames+0x97/0x340 net/ipv4/tcp_output.c:2966
tcp_push_pending_frames include/net/tcp.h:2012 [inline]
tcp_data_snd_check net/ipv4/tcp_input.c:5656 [inline]
tcp_rcv_established+0xfb0/0x1d20 net/ipv4/tcp_input.c:6090
tcp_v4_do_rcv+0x4ed/0xb80 net/ipv4/tcp_ipv4.c:1735
tcp_v4_rcv+0x23bf/0x2af0 net/ipv4/tcp_ipv4.c:2167
ip_protocol_deliver_rcu+0x20e/0x3f0 net/ipv4/ip_input.c:205
ip_local_deliver_finish+0x2ca/0x510 net/ipv4/ip_input.c:233
NF_HOOK+0x32d/0x3b0 include/linux/netfilter.h:304
dst_input include/net/dst.h:477 [inline]
ip_sublist_rcv_finish net/ipv4/ip_input.c:580 [inline]
ip_list_rcv_finish net/ipv4/ip_input.c:631 [inline]
ip_sublist_rcv+0xa4c/0xd70 net/ipv4/ip_input.c:639
ip_list_rcv+0x3f2/0x440 net/ipv4/ip_input.c:674
__netif_receive_skb_list_ptype net/core/dev.c:5689 [inline]
__netif_receive_skb_list_core+0x583/0x750 net/core/dev.c:5737
__netif_receive_skb_list net/core/dev.c:5789 [inline]
netif_receive_skb_list_internal+0x943/0xca0 net/core/dev.c:5880
gro_normal_list include/net/gro.h:451 [inline]
gro_normal_one include/net/gro.h:464 [inline]
napi_skb_finish net/core/gro.c:575 [inline]
napi_gro_receive+0x565/0xb00 net/core/gro.c:605
receive_buf+0x2203/0x3820 drivers/net/virtio_net.c:1870
virtnet_receive drivers/net/virtio_net.c:2155 [inline]
virtnet_poll+0x5dd/0x1280 drivers/net/virtio_net.c:2229
__napi_poll+0xc0/0x460 net/core/dev.c:6650
napi_poll net/core/dev.c:6717 [inline]
net_rx_action+0x616/0xc40 net/core/dev.c:6853
handle_softirqs+0x280/0x820 kernel/softirq.c:578
__do_softirq kernel/softirq.c:612 [inline]
invoke_softirq kernel/softirq.c:452 [inline]
__irq_exit_rcu+0xd3/0x190 kernel/softirq.c:661
irq_exit_rcu+0x9/0x20 kernel/softirq.c:673
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:generic_exec_single+0x481/0x4f0 kernel/smp.c:418
Code: 75 11 e8 42 05 0b 00 48 85 db 75 16 e8 38 05 0b 00 eb 15 e8 31 05 0b 00 e8 0c 2e 0a 09 48 85 db 74 ea e8 22 05 0b 00 fb 31 c0 <48> c7 44 24 20 0e 36 e0 45 4b c7 04 2c 00 00 00 00 43 c7 44 2c 08
RSP: 0018:ffffc9000fae7a00 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000200 RCX: 0000000000080000
RDX: ffffc9000caea000 RSI: 0000000000001b76 RDI: 0000000000001b77
RBP: ffffc9000fae7ad0 R08: ffffffff911c55ff R09: 1ffffffff2238abf
R10: dffffc0000000000 R11: fffffbfff2238ac0 R12: 1ffff92001f5cf44
R13: dffffc0000000000 R14: 0000000000000000 R15: 1ffff92001f5cf65
smp_call_function_single+0x36d/0x5a0 kernel/smp.c:647
task_function_call kernel/events/core.c:120 [inline]
perf_install_in_context+0x5be/0x920 kernel/events/core.c:2959
__do_sys_perf_event_open kernel/events/core.c:12957 [inline]
__se_sys_perf_event_open+0x1836/0x1c50 kernel/events/core.c:12609
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f186259cdd9
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:00007f18634ab028 EFLAGS: 00000246 ORIG_RAX: 000000000000012a
RAX: ffffffffffffffda RBX: 00007f1862815fa0 RCX: 00007f186259cdd9
RDX: ffffffffffffffff RSI: 0000000000000000 RDI: 0000200000000480
RBP: 00007f1862632d69 R08: 000000000000000a R09: 0000000000000000
R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1862816038 R14: 00007f1862815fa0 R15: 00007ffdd6623c38