rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 1-....: (10385 ticks this GP) idle=118c/1/0x4000000000000000 softirq=41312/41312 fqs=3397
rcu: hardirqs softirqs csw/system
rcu: number: 1144850 0 0
rcu: cputime: 15180 31962 45 ==> 47180(ms)
rcu: (t=10504 jiffies g=52677 q=788 ncpus=2)
rcu: rcu_preempt kthread timer wakeup didn't happen for 1137 jiffies! g52677 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: Possible timer handling issue on cpu=0 timer-softirq=34767
rcu: rcu_preempt kthread starved for 1140 jiffies! g52677 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:26952 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 01/24/2026
RIP: 0010:pv_native_safe_halt+0xf/0x10 arch/x86/kernel/paravirt.c:148
Code: e7 22 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 83 f1 43 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: ffffffff8acac900 RDI: ffffffff8b1c81e0
RBP: ffffc900000079b0 R08: ffffffff911bf5c7 R09: 1ffffffff2237eb8
R10: dffffc0000000000 R11: fffffbfff2237eb9 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: 00007ffdae6a8ca0 CR3: 000000000cf32000 CR4: 00000000003506f0
DR0: 0000200000000300 DR1: 0000200000000300 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: e7 22 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 83 f1 43 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: 000002c2
RAX: 7030ce8226c77f00 RBX: ffffffff8162a490 RCX: 7030ce8226c77f00
RDX: 0000000000000001 RSI: ffffffff8acac900 RDI: ffffffff8b1c81e0
RBP: ffffffff8ce07eb8 R08: ffff8880b8e36b2b R09: 1ffff110171c6d65
R10: dffffc0000000000 R11: ffffed10171c6d66 R12: 1ffffffff19d2688
R13: 1ffffffff19c0fbc R14: 0000000000000000 R15: dffffc0000000000
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:170 [inline]
do_idle+0x1f0/0x4e0 kernel/sched/idle.c:282
cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:380
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: 12931 Comm: syz.1.1940 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
RIP: 0010:unwind_next_frame+0xcd6/0x2970 arch/x86/kernel/unwind_orc.c:-1
Code: 84 c0 0f 85 07 1b 00 00 4c 89 f0 48 c1 e8 03 42 0f b6 04 28 84 c0 48 8b 6c 24 10 48 8b 54 24 08 0f 85 08 1b 00 00 48 0f bf 03 <48> 01 c2 e9 1c 01 00 00 e8 ad d1 4b 00 e9 5e 0c 00 00 e8 a3 d1 4b
RSP: 0018:ffffc900001eea98 EFLAGS: 00000246
RAX: 0000000000000010 RBX: ffffffff8f1995be RCX: ffff888028cc8000
RDX: ffffc900001eeef0 RSI: ffffffff8cfa0760 RDI: 0000000000000005
RBP: ffffc900001eebb8 R08: ffff888028cc8000 R09: 0000000000000008
R10: 0000000000000009 R11: 0000000000000100 R12: ffffc900001eeb68
R13: dffffc0000000000 R14: ffffffff8f1995bf R15: ffffffff8f1995c2
FS: 00007f432767a6c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000100000002 CR3: 0000000025503000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000200000000300 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
arch_stack_walk+0x144/0x190 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0xaa/0x100 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:46 [inline]
kasan_set_track+0x4e/0x70 mm/kasan/common.c:53
kasan_save_free_info+0x2e/0x50 mm/kasan/generic.c:522
____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:237
kasan_slab_free include/linux/kasan.h:164 [inline]
slab_free_hook mm/slub.c:1811 [inline]
slab_free_freelist_hook+0x130/0x1a0 mm/slub.c:1837
slab_free mm/slub.c:3830 [inline]
kmem_cache_free+0xf8/0x270 mm/slub.c:3852
packet_rcv+0x16b/0x13d0 net/packet/af_packet.c:2278
dev_queue_xmit_nit+0xb16/0xbb0 net/core/dev.c:2385
xmit_one net/core/dev.c:3628 [inline]
dev_hard_start_xmit+0x148/0x740 net/core/dev.c:3648
sch_direct_xmit+0x25e/0x4c0 net/sched/sch_generic.c:345
__dev_xmit_skb net/core/dev.c:3869 [inline]
__dev_queue_xmit+0x179c/0x36b0 net/core/dev.c:4404
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+0x1cbd/0x32f0 net/ipv4/tcp_output.c:1422
tcp_transmit_skb net/ipv4/tcp_output.c:1440 [inline]
__tcp_retransmit_skb+0xa37/0x1500 net/ipv4/tcp_output.c:3373
tcp_retransmit_skb+0x32/0x360 net/ipv4/tcp_output.c:3396
tcp_xmit_retransmit_queue+0x476/0xb30 net/ipv4/tcp_output.c:3478
tcp_xmit_recovery net/ipv4/tcp_input.c:3868 [inline]
tcp_ack+0x47a5/0x6620 net/ipv4/tcp_input.c:4038
tcp_rcv_established+0x7fd/0x1d20 net/ipv4/tcp_input.c:6160
tcp_v4_do_rcv+0x4ed/0xb80 net/ipv4/tcp_ipv4.c:1734
tcp_v4_rcv+0x23bf/0x2af0 net/ipv4/tcp_ipv4.c:2166
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:5664 [inline]
__netif_receive_skb_list_core+0x583/0x750 net/core/dev.c:5712
__netif_receive_skb_list net/core/dev.c:5764 [inline]
netif_receive_skb_list_internal+0x943/0xca0 net/core/dev.c:5855
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:573 [inline]
napi_gro_receive+0x565/0xb00 net/core/gro.c:603
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:6625
napi_poll net/core/dev.c:6692 [inline]
net_rx_action+0x616/0xc40 net/core/dev.c:6828
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:finish_task_switch+0x26a/0x8f0 kernel/sched/core.c:5255
Code: 0f 84 33 01 00 00 48 85 db 0f 85 52 01 00 00 0f 1f 44 00 00 4c 8b 75 d0 4c 89 e7 e8 f0 93 30 09 e8 7b 23 30 00 fb 4c 8b 65 c0 <49> 8d bc 24 f8 15 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 28 84 c0
RSP: 0018:ffffc9000eea7778 EFLAGS: 00000286
RAX: 33fffad5b6bc5100 RBX: 0000000000000000 RCX: 33fffad5b6bc5100
RDX: dffffc0000000000 RSI: ffffffff8acac900 RDI: ffffffff8b1c81e0
RBP: ffffc9000eea77d0 R08: ffffffff8e8add2f R09: 1ffffffff1d15ba5
R10: dffffc0000000000 R11: fffffbfff1d15ba6 R12: ffff888028cc8000
R13: dffffc0000000000 R14: ffff888028ccbc00 R15: ffff8880b8f3cac8
context_switch kernel/sched/core.c:5384 [inline]
__schedule+0x155b/0x45a0 kernel/sched/core.c:6700
preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6867
preempt_schedule+0xc0/0xd0 kernel/sched/core.c:6891
preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45
__raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline]
_raw_spin_unlock+0x3a/0x40 kernel/locking/spinlock.c:186
spin_unlock include/linux/spinlock.h:391 [inline]
futex_queue kernel/futex/futex.h:174 [inline]
futex_wait_queue+0x9d/0x1b0 kernel/futex/waitwake.c:338
futex_wait+0x1ec/0x5e0 kernel/futex/waitwake.c:656
do_futex+0x2ff/0x3e0 kernel/futex/syscalls.c:134
__do_sys_futex kernel/futex/syscalls.c:211 [inline]
__se_sys_futex+0x3a9/0x440 kernel/futex/syscalls.c:192
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: 0033:0x7f432679aeb9
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:00007f432767a0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 00007f4326a16188 RCX: 00007f432679aeb9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f4326a16188
RBP: 00007f4326a16180 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4326a16218 R14: 00007ffcfd5f0780 R15: 00007ffcfd5f0868