rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 1-....: (10500 ticks this GP) idle=07cc/1/0x4000000000000000 softirq=36397/36397 fqs=72
rcu: hardirqs softirqs csw/system
rcu: number: 967839 0 0
rcu: cputime: 7938 22915 26 ==> 30890(ms)
rcu: (t=10503 jiffies g=44773 q=681 ncpus=2)
rcu: rcu_preempt kthread timer wakeup didn't happen for 3084 jiffies! g44773 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: Possible timer handling issue on cpu=0 timer-softirq=20936
rcu: rcu_preempt kthread starved for 3087 jiffies! g44773 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:27208 pid:17 ppid:2 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5380 [inline]
__schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
schedule+0xbd/0x170 kernel/sched/core.c:6773
schedule_timeout+0x160/0x280 kernel/time/timer.c:2168
rcu_gp_fqs_loop+0x302/0x1560 kernel/rcu/tree.c:1667
rcu_gp_kthread+0x99/0x380 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: 5752 Comm: syz-executor Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:148
Code: 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 23 bb 40 00 f3 0f 1e fa fb f4 cc cc cc cc cc cc cc cc cc cc cc cc 66 0f 1f 00 55 41 57 41 56
RSP: 0018:ffffc900043976f8 EFLAGS: 000002d3
RAX: ffffffff813a13aa RBX: 0000000000000003 RCX: ffff888021193c00
RDX: 0000000000000000 RSI: ffffffff8aaabce0 RDI: ffffffff8afc6f80
RBP: ffffc900043977d0 R08: ffffffff90d945c7 R09: 1ffffffff21b28b8
R10: dffffc0000000000 R11: fffffbfff21b28b9 R12: dffffc0000000000
R13: 0000000000000200 R14: 0000000000000003 R15: 1ffff92000872ee4
FS: 000055558bd06500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055558feb15c8 CR3: 000000001ca93000 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+0x22f/0x290 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+0x24e/0x2c0 kernel/locking/spinlock_debug.c:115
spin_lock_bh include/linux/spinlock.h:356 [inline]
lock_sock_nested+0x6a/0x100 net/core/sock.c:3538
lock_sock include/net/sock.h:1767 [inline]
tcp_recvmsg+0x1fa/0x810 net/ipv4/tcp.c:2603
inet_recvmsg+0x130/0x1e0 net/ipv4/af_inet.c:882
sock_recvmsg_nosec net/socket.c:1046 [inline]
sock_recvmsg net/socket.c:1068 [inline]
sock_read_iter+0x2b7/0x3b0 net/socket.c:1138
call_read_iter include/linux/fs.h:2012 [inline]
new_sync_read fs/read_write.c:389 [inline]
vfs_read+0x431/0x920 fs/read_write.c:470
ksys_read+0x147/0x250 fs/read_write.c:613
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7efd5e18e11d
Code: a8 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff eb bd e8 a8 48 00 00 0f 1f 84 00 00 00 00 00 80 3d 41 d4 22 00 00 74 17 31 c0 0f 05 <48> 3d 00 f0 ff ff 77 5b c3 66 2e 0f 1f 84 00 00 00 00 00 48 83 ec
RSP: 002b:00007ffe3bd5d3a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: ffffffffffffffff RCX: 00007efd5e18e11d
RDX: 0000000000000cb0 RSI: 000055558bd29a7c RDI: 0000000000000003
RBP: 00000000000015fc R08: 0000000000000150 R09: 0000000000745a0f
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe3bd5d7d0
R13: 00000000000022ac R14: 000055558bd28480 R15: 00007ffe3bd5d450
CPU: 1 PID: 11724 Comm: syz.5.1650 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:orc_ip arch/x86/kernel/unwind_orc.c:80 [inline]
RIP: 0010:__orc_find arch/x86/kernel/unwind_orc.c:102 [inline]
RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:227 [inline]
RIP: 0010:unwind_next_frame+0x4a3/0x2970 arch/x86/kernel/unwind_orc.c:494
Code: 74 24 48 48 89 d8 4c 29 e0 48 89 c1 48 c1 f9 02 48 c1 e8 3f 48 01 c8 48 83 e0 fe 4d 8d 3c 44 4c 89 f8 48 c1 e8 03 0f b6 04 10 <84> c0 75 3e 4d 63 2f 4d 01 fd 4c 89 ef 4c 89 f6 e8 d8 ea 4a 00 49
RSP: 0018:ffffc900001eed90 EFLAGS: 00000a03
RAX: 0000000000000000 RBX: ffffffff8e59457c RCX: 0000000000000004
RDX: dffffc0000000000 RSI: 000000000000ae0a RDI: 000000000000ae0f
RBP: ffffffff8e59456c R08: ffff88802bcd3c00 R09: 0000000000000003
R10: 0000000000000004 R11: 0000000000000100 R12: ffffffff8e59456c
R13: 000000000000ae0a R14: ffffffff81321d67 R15: ffffffff8e594574
FS: 00007f5ffaf856c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000100000000 CR3: 00000000432b1000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000200000000300
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
__unwind_start+0x66a/0x7e0 arch/x86/kernel/unwind_orc.c:760
unwind_start arch/x86/include/asm/unwind.h:64 [inline]
arch_stack_walk+0xf8/0x190 arch/x86/kernel/stacktrace.c:24
stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:45 [inline]
kasan_set_track+0x4e/0x70 mm/kasan/common.c:52
kasan_save_free_info+0x2e/0x50 mm/kasan/generic.c:522
____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:236
kasan_slab_free include/linux/kasan.h:164 [inline]
slab_free_hook mm/slub.c:1811 [inline]
slab_free_freelist_hook+0x130/0x1b0 mm/slub.c:1837
slab_free mm/slub.c:3830 [inline]
kmem_cache_free+0xf8/0x280 mm/slub.c:3852
dev_kfree_skb_any_reason+0x10c/0x120 net/core/dev.c:3228
free_old_xmit_skbs+0x114/0x3c0 drivers/net/virtio_net.c:780
start_xmit+0x161/0x1420 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:3619 [inline]
dev_hard_start_xmit+0x246/0x740 net/core/dev.c:3635
sch_direct_xmit+0x252/0x4a0 net/sched/sch_generic.c:345
__dev_xmit_skb net/core/dev.c:3856 [inline]
__dev_queue_xmit+0x173e/0x35a0 net/core/dev.c:4391
neigh_output include/net/neighbour.h:543 [inline]
ip_finish_output2+0xd21/0x11d0 net/ipv4/ip_output.c:235
dst_output include/net/dst.h:467 [inline]
ip_local_out net/ipv4/ip_output.c:129 [inline]
__ip_queue_xmit+0x10aa/0x1a10 net/ipv4/ip_output.c:535
__tcp_transmit_skb+0x1c97/0x32a0 net/ipv4/tcp_output.c:1422
tcp_ack_snd_check net/ipv4/tcp_input.c:5728 [inline]
tcp_rcv_established+0xb00/0x1cf0 net/ipv4/tcp_input.c:6174
tcp_v4_do_rcv+0x4ed/0xb80 net/ipv4/tcp_ipv4.c:1734
tcp_v4_rcv+0x2334/0x2a50 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+0x303/0x390 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+0xa38/0xd20 net/ipv4/ip_input.c:639
ip_list_rcv+0x3e3/0x430 net/ipv4/ip_input.c:674
__netif_receive_skb_list_ptype net/core/dev.c:5651 [inline]
__netif_receive_skb_list_core+0x578/0x740 net/core/dev.c:5699
__netif_receive_skb_list net/core/dev.c:5751 [inline]
netif_receive_skb_list_internal+0x91b/0xc60 net/core/dev.c:5842
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+0x218c/0x3780 drivers/net/virtio_net.c:1870
virtnet_receive drivers/net/virtio_net.c:2155 [inline]
virtnet_poll+0x61f/0x1180 drivers/net/virtio_net.c:2229
__napi_poll+0xc0/0x460 net/core/dev.c:6612
napi_poll net/core/dev.c:6679 [inline]
net_rx_action+0x5ea/0xbf0 net/core/dev.c:6815
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+0xc7/0x190 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:lock_acquire+0x1f2/0x410 kernel/locking/lockdep.c:5758
Code: 00 9c 8f 84 24 80 00 00 00 f6 84 24 81 00 00 00 02 0f 85 f5 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 04 3c 00 00 00 00 66 43 c7 44 3c 09 00 00 43 c6 44 3c 0b 00
RSP: 0018:ffffc900038176a0 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000001 RCX: e2e2ecc9d26a8800
RDX: 0000000000000000 RSI: ffffffff8aaace60 RDI: ffffffff8afc6f80
RBP: ffffc900038177a8 R08: dffffc0000000000 R09: 1ffffffff21b28a0
R10: dffffc0000000000 R11: fffffbfff21b28a1 R12: 1ffff92000702ee0
R13: ffffffff8d3d58a0 R14: 0000000000000246 R15: dffffc0000000000
debug_objects_fill_pool+0x92/0x6b0 lib/debugobjects.c:615
debug_object_activate+0x36/0x4b0 lib/debugobjects.c:705
debug_rcu_head_queue kernel/rcu/rcu.h:227 [inline]
__call_rcu_common kernel/rcu/tree.c:2706 [inline]
call_rcu+0xab/0x930 kernel/rcu/tree.c:2837
thread_stack_delayed_free kernel/fork.c:231 [inline]
free_thread_stack kernel/fork.c:337 [inline]
release_task_stack kernel/fork.c:590 [inline]
put_task_stack+0x147/0x200 kernel/fork.c:597
finish_task_switch+0x442/0x920 kernel/sched/core.c:5287
context_switch kernel/sched/core.c:5383 [inline]
__schedule+0x14da/0x44d0 kernel/sched/core.c:6699
preempt_schedule_irq+0xb5/0x140 kernel/sched/core.c:7009
irqentry_exit+0x67/0x70 kernel/entry/common.c:438
asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:692
RIP: 0010:exit_to_user_mode_loop+0x40/0x110 kernel/entry/common.c:164
Code: fb eb 1d e8 82 02 f5 08 65 48 8b 05 da 2b 91 7e 4c 8b 30 41 f7 c6 0e 30 02 00 0f 84 c4 00 00 00 e8 d5 69 19 00 fb 41 f6 c6 08 <74> 05 e8 59 2a fd 08 41 f7 c6 00 10 00 00 74 08 48 89 df e8 28 ea
RSP: 0018:ffffc90003817ed0 EFLAGS: 00000246
RAX: e2e2ecc9d26a8800 RBX: ffffc90003817f58 RCX: e2e2ecc9d26a8800
RDX: dffffc0000000000 RSI: ffffffff8aaabce0 RDI: ffffffff8afc6f80
RBP: ffffc90003817f48 R08: ffffffff8e4a212f R09: 1ffffffff1c94425
R10: dffffc0000000000 R11: fffffbfff1c94426 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000004006 R15: ffff88802bcd3c00
exit_to_user_mode_prepare+0xf6/0x180 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:87
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f5ffa18f749
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f5ffaf850e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: 0000000000000000 RBX: 00007f5ffa3e5fa8 RCX: 00007f5ffa18f749
RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007f5ffa3e5fac
RBP: 00007f5ffa3e5fa0 R08: 0000000000745a0f R09: 0000000000000000
R10: 0000000000000009 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5ffa3e6038 R14: 00007ffcbecec500 R15: 00007ffcbecec5e8