rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 0-....: (7623 ticks this GP) idle=76fc/1/0x4000000000000000 softirq=16462/16462 fqs=2838
rcu: hardirqs softirqs csw/system
rcu: number: 1330374 0 0
rcu: cputime: 13942 38537 63 ==> 52480(ms)
rcu: (t=10500 jiffies g=18509 q=2633 ncpus=2)
rcu: rcu_preempt kthread timer wakeup didn't happen for 3250 jiffies! g18509 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: Possible timer handling issue on cpu=1 timer-softirq=11868
rcu: rcu_preempt kthread starved for 3257 jiffies! g18509 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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: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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 0 Comm: swapper/1 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:ffffc900001f09c0 EFLAGS: 00000206
RAX: 0000000000000000 RBX: ffff88801e661918 RCX: ffff88801c253c00
RDX: 0000000000000100 RSI: ffffffff8acac900 RDI: ffffffff8b1c80e0
RBP: ffffc900001f0ab0 R08: ffffffff911be5c7 R09: 1ffffffff2237cb8
R10: dffffc0000000000 R11: fffffbfff2237cb9 R12: 1ffff110171e0001
R13: 00000000ffffd017 R14: 1ffff11003ccc323 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055aa89b8cf30 CR3: 000000000cf32000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 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]
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: 18 23 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 43 32 44 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:ffffc90000187de0 EFLAGS: 000002c2
RAX: 9991084b51471800 RBX: ffffffff8162a570 RCX: 9991084b51471800
RDX: 0000000000000001 RSI: ffffffff8acac900 RDI: ffffffff8b1c80e0
RBP: ffffc90000187f20 R08: ffff8880b8f36b2b R09: 1ffff110171e6d65
R10: dffffc0000000000 R11: ffffed10171e6d66 R12: 1ffff1100384a780
R13: 1ffff92000030fc8 R14: 0000000000000001 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
start_secondary+0xee/0xf0 arch/x86/kernel/smpboot.c:323
secondary_startup_64_no_verify+0x179/0x17b
CPU: 0 PID: 7074 Comm: syz.1.402 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xc0/0x120 kernel/locking/spinlock.c:194
Code: c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f7 44 24 20 00 02 00 00 41 c6 04 07 f8 75 4b f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 bb ca ce f6 65 8b 05 ac 00 76 75 85 c0 74 3c 48 c7 04 24 0e 36
RSP: 0018:ffffc90000005d20 EFLAGS: 00000206
RAX: dffffc0000000004 RBX: 0000000000000a02 RCX: 4c0978fd0a6f2300
RDX: dffffc0000000000 RSI: ffffffff8acac900 RDI: 0000000000000001
RBP: ffffc90000005db8 R08: ffffffff911be5c7 R09: 1ffffffff2237cb8
R10: dffffc0000000000 R11: fffffbfff2237cb9 R12: dffffc0000000000
R13: ffff88802797cac0 R14: ffffffff8d7ee060 R15: 1ffff92000000ba4
FS: 00007f68afdf66c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000100000000 CR3: 0000000024128000 CR4: 00000000003506f0
DR0: 0000200000000300 DR1: 0000200000000300 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
__stack_depot_save+0x560/0x630 lib/stackdepot.c:439
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_set_track+0x5f/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_transmit_skb net/ipv4/tcp_output.c:1440 [inline]
tcp_write_xmit+0x174c/0x62e0 net/ipv4/tcp_output.c:2778
__tcp_push_pending_frames+0x97/0x340 net/ipv4/tcp_output.c:2963
tcp_push_pending_frames include/net/tcp.h:2012 [inline]
tcp_data_snd_check net/ipv4/tcp_input.c:5656 [inline]
tcp_rcv_established+0xab3/0x1d20 net/ipv4/tcp_input.c:6173
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_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: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:generic_exec_single+0x481/0x4f0 kernel/smp.c:418
Code: 75 11 e8 02 02 0b 00 48 85 db 75 16 e8 f8 01 0b 00 eb 15 e8 f1 01 0b 00 e8 8c fa 07 09 48 85 db 74 ea e8 e2 01 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:ffffc9000bc0fa00 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000200 RCX: 0000000000080000
RDX: ffffc9000ccea000 RSI: 000000000000442c RDI: 000000000000442d
RBP: ffffc9000bc0fad0 R08: ffffffff911be5ff R09: 1ffffffff2237cbf
R10: dffffc0000000000 R11: fffffbfff2237cc0 R12: 1ffff92001781f44
R13: dffffc0000000000 R14: 0000000000000000 R15: 1ffff92001781f65
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:2948
__do_sys_perf_event_open kernel/events/core.c:12915 [inline]
__se_sys_perf_event_open+0x1836/0x1c50 kernel/events/core.c:12567
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: 0033:0x7f68b1b9acb9
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:00007f68afdf6028 EFLAGS: 00000246 ORIG_RAX: 000000000000012a
RAX: ffffffffffffffda RBX: 00007f68b1e15fa0 RCX: 00007f68b1b9acb9
RDX: ffffffffffffffff RSI: 0000000000000000 RDI: 0000200000000480
RBP: 00007f68b1c08bf7 R08: 000000000000000a R09: 0000000000000000
R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000
R13: 00007f68b1e16038 R14: 00007f68b1e15fa0 R15: 00007ffdecc78018