rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 1-...!: (1 GPs behind) idle=8134/1/0x4000000000000000 softirq=80531/80532 fqs=31
rcu: (t=10502 jiffies g=108473 q=523 ncpus=2)
rcu: rcu_preempt kthread starved for 10441 jiffies! g108473 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:26888 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: 20638 Comm: syz.2.5152 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:434 [inline]
RIP: 0010:__pv_queued_spin_lock_slowpath+0x532/0x9d0 kernel/locking/qspinlock.c:511
Code: 00 41 c6 45 00 00 48 8b 44 24 10 42 0f b6 04 38 84 c0 0f 85 1b 01 00 00 48 8b 44 24 08 c6 00 01 41 bd 00 80 ff ff eb 07 f3 90 <41> ff c5 74 47 43 0f b6 04 3e 84 c0 75 2b 80 3b 00 75 eb 48 89 df
RSP: 0018:ffffc900044ff8a0 EFLAGS: 00000206
RAX: 0000000000000000 RBX: ffffc90000a27908 RCX: ffff888064695a00
RDX: 0000000000000000 RSI: ffffffff8acac900 RDI: ffffffff8b1c80e0
RBP: ffffc900044ff990 R08: ffffffff911be5ff R09: 1ffffffff2237cbf
R10: dffffc0000000000 R11: fffffbfff2237cc0 R12: 1ffff110171c0001
R13: 00000000ffffbdd1 R14: 1ffff92000144f21 R15: dffffc0000000000
FS: 000055555a2a7500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c2e0b39 CR3: 00000000623d6000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000200000000300 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
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]
futex_q_lock+0x1aa/0x250 kernel/futex/core.c:542
futex_wait_setup+0xed/0x270 kernel/futex/waitwake.c:607
futex_wait+0x1bf/0x5e0 kernel/futex/waitwake.c:651
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: 0033:0x7f0b61b9aeb9
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:00007ffe382252d8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 00000000000e9552 RCX: 00007f0b61b9aeb9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f0b61e15fac
RBP: 0000000000000226 R08: 0000000000745b7e R09: 0000000000000000
R10: 00007ffe382253e0 R11: 0000000000000246 R12: 00007ffe38225400
R13: 00007f0b61e15fac R14: 00000000000e9778 R15: 00007ffe382253e0
CPU: 1 PID: 20639 Comm: syz.2.5152 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:__is_kernel_text include/asm-generic/sections.h:208 [inline]
RIP: 0010:is_kernel_text include/linux/kallsyms.h:29 [inline]
RIP: 0010:core_kernel_text kernel/extable.c:68 [inline]
RIP: 0010:kernel_text_address+0x5/0xd0 kernel/extable.c:99
Code: 00 00 48 81 fb 00 00 dd 8f 0f 93 c1 48 81 fb 0b ca f3 8f 0f 92 c2 20 ca 08 c2 0f b6 c2 5b c3 66 0f 1f 44 00 00 66 0f 1f 00 55 <41> 56 53 48 81 ff 00 00 00 81 0f 93 c0 48 81 ff 00 00 c0 8a 0f 92
RSP: 0018:ffffc900001eeca0 EFLAGS: 00000246
RAX: ffffffff813b34b7 RBX: ffffffff817b4e89 RCX: 0000000000000100
RDX: ffff88802d24da00 RSI: 0000000000000001 RDI: ffffffff817b4e89
RBP: 0000000000000001 R08: ffff88802d24da00 R09: 0000000000000003
R10: 0000000000000004 R11: 0000000000000100 R12: ffffffff817b496d
R13: ffffc900001ef0f8 R14: dffffc0000000000 R15: 1ffff9200003dda6
FS: 00007f0b62b0c6c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000100000000 CR3: 00000000623d6000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000200000000300
DR3: 0000000000000000 DR6: 00000000ffff0ff1 DR7: 0000000000000600
Call Trace:
__kernel_text_address+0xd/0x30 kernel/extable.c:79
unwind_get_return_address+0x5d/0xc0 arch/x86/kernel/unwind_orc.c:369
arch_stack_walk+0x11d/0x190 arch/x86/kernel/stacktrace.c:26
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
skb_kfree_head net/core/skbuff.c:947 [inline]
skb_free_head net/core/skbuff.c:961 [inline]
skb_release_data+0x60a/0x800 net/core/skbuff.c:991
skb_release_all net/core/skbuff.c:1057 [inline]
__kfree_skb net/core/skbuff.c:1071 [inline]
kfree_skb_reason+0x10e/0x170 net/core/skbuff.c:1107
dev_kfree_skb_any_reason+0x120/0x130 net/core/dev.c:3254
free_old_xmit_skbs+0x11a/0x3d0 drivers/net/virtio_net.c:780
start_xmit+0x161/0x1410 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:3645 [inline]
dev_hard_start_xmit+0x246/0x740 net/core/dev.c:3661
sch_direct_xmit+0x25e/0x4c0 net/sched/sch_generic.c:345
__dev_xmit_skb net/core/dev.c:3882 [inline]
__dev_queue_xmit+0x179c/0x36b0 net/core/dev.c:4417
dev_queue_xmit include/linux/netdevice.h:3113 [inline]
neigh_hh_output include/net/neighbour.h:527 [inline]
neigh_output include/net/neighbour.h:541 [inline]
ip_finish_output2+0xcec/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_validate_incoming+0xf13/0x2250 net/ipv4/tcp_input.c:5891
tcp_rcv_established+0x7de/0x1d20 net/ipv4/tcp_input.c:6156
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:5681 [inline]
__netif_receive_skb_list_core+0x583/0x750 net/core/dev.c:5729
__netif_receive_skb_list net/core/dev.c:5781 [inline]
netif_receive_skb_list_internal+0x943/0xca0 net/core/dev.c:5872
gro_normal_list include/net/gro.h:451 [inline]
gro_normal_one include/net/gro.h:464 [inline]
napi_gro_complete+0x290/0x660 net/core/gro.c:262
dev_gro_receive+0x19cd/0x22c0 net/core/gro.c:500
napi_gro_receive+0x381/0xb00 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:6642
napi_poll net/core/dev.c:6709 [inline]
net_rx_action+0x616/0xc50 net/core/dev.c:6846
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:__raw_callee_save___pv_queued_spin_unlock+0x0/0x16
Code: 56 57 41 50 41 51 41 52 41 53 e8 8b 08 00 00 41 5b 41 5a 41 59 41 58 5f 5e 5a 59 c3 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 52 b8 01 00 00 00 31 d2 f0 0f b0 17 3c 01 75 02 5a c3
RSP: 0018:ffffc9000483fbd0 EFLAGS: 00000286
RAX: 1ffffffff19f3e28 RBX: ffffc90000a27908 RCX: 0000000000000001
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffffc90000a27908
RBP: 1ffff92000144f22 R08: ffffc90000a2790b R09: 1ffff92000144f21
R10: dffffc0000000000 R11: fffff52000144f22 R12: dffffc0000000000
R13: 1ffff92000144f23 R14: ffffc90000a27918 R15: ffffc90000a27910
pv_queued_spin_unlock arch/x86/include/asm/paravirt.h:591 [inline]
queued_spin_unlock arch/x86/include/asm/qspinlock.h:57 [inline]
do_raw_spin_unlock+0x121/0x230 kernel/locking/spinlock_debug.c:141
__raw_spin_unlock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_unlock+0x1e/0x40 kernel/locking/spinlock.c:186
spin_unlock include/linux/spinlock.h:391 [inline]
futex_wake+0x41d/0x4f0 kernel/futex/waitwake.c:183
do_futex+0x35d/0x3e0 kernel/futex/syscalls.c:139
__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: 0033:0x7f0b61b9aeb9
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:00007f0b62b0c0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 00007f0b61e15fa8 RCX: 00007f0b61b9aeb9
RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007f0b61e15fac
RBP: 00007f0b61e15fa0 R08: 0000000000745b7e R09: 0000000000000000
R10: 0000000000000009 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0b61e16038 R14: 00007ffe38225090 R15: 00007ffe38225178