GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog
GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-...!: (2 ticks this GP) idle=974c/1/0x4000000000000000 softirq=131884/131884 fqs=9
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P26206/1:b.el
rcu: (detected by 1, t=10502 jiffies, g=164209, q=475 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 25277 Comm: kworker/0:2 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: events_power_efficient neigh_periodic_work
RIP: 0010:check_preemption_disabled+0x15/0xd0 lib/smp_processor_id.c:16
Code: 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 41 57 41 56 53 65 8b 05 db 4d af 07 65 48 8b 0d ab 4d af 07 <85> c9 74 0c 5b 41 5e 41 5f 5d c3 cc cc cc cc cc 9c 59 f7 c1 00 02
RSP: 0018:ffffc90000007d60 EFLAGS: 00000046
RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000001000403
RDX: 0000000001000401 RSI: ffffffff8e69c835 RDI: ffffffff8c6da080
RBP: 00000000ffffffff R08: 0000000001000001 R09: 0000000000000000
R10: ffff888026819308 R11: ffffed1004d03263 R12: 0000000000000046
R13: ffff888034965dc0 R14: ffff8880b8628298 R15: 0000000000000006
FS: 0000000000000000(0000) GS:ffff888124cce000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fab2ba13809 CR3: 000000007be1c000 CR4: 00000000003526f0
Call Trace:
lockdep_recursion_finish kernel/locking/lockdep.c:470 [inline]
lock_is_held_type+0xdf/0x150 kernel/locking/lockdep.c:6017
lock_is_held include/linux/lockdep.h:249 [inline]
__run_hrtimer kernel/time/hrtimer.c:2040 [inline]
__hrtimer_run_queues+0x20b/0xa10 kernel/time/hrtimer.c:2131
hrtimer_interrupt+0x4cd/0xaa0 kernel/time/hrtimer.c:2250
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1051 [inline]
__sysvec_apic_timer_interrupt+0x102/0x430 arch/x86/kernel/apic/apic.c:1068
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1062
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:on_stack arch/x86/include/asm/stacktrace.h:56 [inline]
RIP: 0010:unwind_next_frame+0x1a3c/0x2550 arch/x86/kernel/unwind_orc.c:694
Code: 89 f8 48 c1 e8 03 80 3c 18 00 74 05 e8 ed ce bf 00 4d 8b 66 08 49 8d 5e 10 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 48 89 df e8 c6 ce bf 00 48 8b 03 4d 39 fc 0f 96
RSP: 0018:ffffc900039bf420 EFLAGS: 00000a02
RAX: 1ffff92000737e9b RBX: ffffc900039bf4d8 RCX: dffffc0000000000
RDX: ffffc900039bf508 RSI: dffffc0000000000 RDI: ffffc900039bf4d0
RBP: 1ffffffff2240e01 R08: ffffc900039bf870 R09: 0000000000000000
R10: ffffc900039bf518 R11: fffff52000737ea5 R12: ffffc900039b8000
R13: ffffffff8177f1df R14: ffffc900039bf4c8 R15: ffffc900039bf880
arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:584
poison_slab_object mm/kasan/common.c:253 [inline]
__kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
kasan_slab_free include/linux/kasan.h:235 [inline]
slab_free_hook mm/slub.c:2748 [inline]
slab_free mm/slub.c:6508 [inline]
kmem_cache_free+0x182/0x650 mm/slub.c:6635
netlink_broadcast_filtered+0xd9d/0xea0 net/netlink/af_netlink.c:1560
nlmsg_multicast_filtered include/net/netlink.h:1165 [inline]
nlmsg_multicast include/net/netlink.h:1184 [inline]
nlmsg_notify+0xe3/0x1a0 net/netlink/af_netlink.c:2618
__neigh_notify+0x1ae/0x310 net/core/neighbour.c:3593
neigh_notify net/core/neighbour.c:3604 [inline]
neigh_cleanup_and_release+0xae/0x2b0 net/core/neighbour.c:119
neigh_periodic_work+0xb4a/0xe40 net/core/neighbour.c:1026
process_one_work kernel/workqueue.c:3396 [inline]
process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3479
worker_thread+0xa47/0xfb0 kernel/workqueue.c:3560
kthread+0x38b/0x480 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
task:syz.4.6293 state:R running task stack:25624 pid:26206 tgid:26205 ppid:16364 task_flags:0x400140 flags:0x00080003
Call Trace:
context_switch kernel/sched/core.c:5526 [inline]
__schedule+0x17db/0x58f0 kernel/sched/core.c:7277
preempt_schedule_irq+0x4b/0x90 kernel/sched/core.c:7599
irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline]
irqentry_exit+0x14f/0x910 kernel/entry/common.c:167
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:lock_acquire+0x232/0x350 kernel/locking/lockdep.c:5947
Code: ff ff ff e8 50 85 42 0a f7 44 24 10 00 02 00 00 0f 84 38 ff ff ff 65 48 8b 05 a2 f0 f1 11 48 3b 44 24 50 75 33 fb 48 83 c4 58 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 bf 89 45 0a cc 48 8d 3d 97 4b da
RSP: 0018:ffffc9000eaded00 EFLAGS: 00000296
RAX: 5c8f05e33085a500 RBX: 0000000000000000 RCX: 0000000000000046
RDX: 000000007a964b5e RSI: ffffffff8e69c835 RDI: ffffffff8c6da080
RBP: ffff888055601f40 R08: ffffffff8177f1df R09: 0000000000000000
R10: ffffc9000eadee38 R11: ffffffff81b28ab0 R12: ffffffff8ed5c8e0
R13: 0000000000000002 R14: 0000000000000000 R15: 0000000000000246
rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
rcu_read_lock include/linux/rcupdate.h:849 [inline]
class_rcu_constructor include/linux/rcupdate.h:1216 [inline]
unwind_next_frame+0xac/0x2550 arch/x86/kernel/unwind_orc.c:495
arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
save_stack+0x122/0x230 mm/page_owner.c:183
__set_page_owner+0x8d/0x4c0 mm/page_owner.c:359
set_page_owner include/linux/page_owner.h:33 [inline]
post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1871
prep_new_page mm/page_alloc.c:1879 [inline]
get_page_from_freelist+0x2209/0x2280 mm/page_alloc.c:3943
__alloc_frozen_pages_noprof+0x217/0x5a0 mm/page_alloc.c:5436
alloc_pages_mpol+0x21e/0x390 mm/mempolicy.c:2486
folio_alloc_mpol_noprof+0x39/0x160 mm/mempolicy.c:2505
shmem_alloc_folio mm/shmem.c:1933 [inline]
shmem_alloc_and_add_folio+0x43e/0xf60 mm/shmem.c:1975
shmem_get_folio_gfp+0x5da/0x16d0 mm/shmem.c:2528
shmem_fault+0x179/0x390 mm/shmem.c:2729
__do_fault+0x138/0x2a0 mm/memory.c:5565
do_read_fault mm/memory.c:6000 [inline]
do_fault mm/memory.c:6134 [inline]
do_pte_missing+0x2215/0x34b0 mm/memory.c:4700
handle_pte_fault mm/memory.c:6558 [inline]
__handle_mm_fault mm/memory.c:6707 [inline]
handle_mm_fault+0x1a53/0x3750 mm/memory.c:6876
faultin_page mm/gup.c:1126 [inline]
__get_user_pages+0x1675/0x2750 mm/gup.c:1428
populate_vma_page_range+0x2be/0x3c0 mm/gup.c:1860
__mm_populate+0x25f/0x390 mm/gup.c:1963
mm_populate include/linux/mm.h:4288 [inline]
vm_mmap_pgoff+0x353/0x4e0 mm/util.c:586
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fdfc759e159
RSP: 002b:00007fdfc8460028 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007fdfc7825fa0 RCX: 00007fdfc759e159
RDX: 0000000000000003 RSI: 0000000000b36000 RDI: 0000200000000000
RBP: 00007fdfc763506b R08: ffffffffffffffff R09: 0000000000000000
R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fdfc7826038 R14: 00007fdfc7825fa0 R15: 00007ffffad7d9e8
rcu: rcu_preempt kthread starved for 8717 jiffies! g164209 f0x0 RCU_GP_WAIT_FQS(5) ->state=R ->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:R running task stack:27496 pid:17 tgid:17 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5526 [inline]
__schedule+0x17db/0x58f0 kernel/sched/core.c:7277
__schedule_loop kernel/sched/core.c:7354 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7369
schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x30c/0x11f0 kernel/rcu/tree.c:2122
rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2330
kthread+0x38b/0x480 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 UID: 0 PID: 7968 Comm: kworker/u8:12 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: wg-kex-wg0 wg_packet_handshake_send_worker
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:64
Code: bc 88 02 c3 cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d b3 d1 23 00 fb f4 8c 08 03 00 cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90
RSP: 0018:ffffc90003b5f2c8 EFLAGS: 000002d3
RAX: ffffffff81771e2c RBX: 0000000000000003 RCX: ffff88807acb5dc0
RDX: 0000000000000000 RSI: ffffffff8e413ed7 RDI: ffffffff8c6da080
RBP: 0000000000000003 R08: ffffffff907a417f R09: 1ffffffff20f482f
R10: dffffc0000000000 R11: fffffbfff20f4830 R12: 0000000000000200
R13: 0000000000000000 R14: ffffffff90383bc0 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff888124dce000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3ff2b556c8 CR3: 00000000663c2000 CR4: 00000000003526f0
Call Trace:
arch_safe_halt arch/x86/include/asm/paravirt.h:62 [inline]
kvm_wait+0x111/0x160 arch/x86/kernel/kvm.c:1098
pv_wait arch/x86/include/asm/paravirt-spinlock.h:88 [inline]
pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:466 [inline]
__pv_queued_spin_lock_slowpath+0x74a/0xbc0 kernel/locking/qspinlock.c:347
pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt-spinlock.h:37 [inline]
queued_spin_lock_slowpath arch/x86/include/asm/paravirt-spinlock.h:71 [inline]
queued_spin_lock include/asm-generic/qspinlock.h:115 [inline]
do_raw_spin_lock+0x26c/0x2f0 kernel/locking/spinlock_debug.c:116
spin_lock_bh include/linux/spinlock.h:353 [inline]
___neigh_create+0xf00/0x22b0 net/core/neighbour.c:686
ip6_finish_output2+0xe0f/0x1460 net/ipv6/ip6_output.c:130
NF_HOOK_COND include/linux/netfilter.h:314 [inline]
ip6_output+0x337/0x540 net/ipv6/ip6_output.c:248
ip6tunnel_xmit include/net/ip6_tunnel.h:174 [inline]
udp_tunnel6_xmit_skb+0x6d9/0xd60 net/ipv6/ip6_udp_tunnel.c:112
send6+0x5ce/0x920 drivers/net/wireguard/socket.c:151
wg_socket_send_skb_to_peer+0x111/0x1d0 drivers/net/wireguard/socket.c:177
wg_packet_send_handshake_initiation drivers/net/wireguard/send.c:40 [inline]
wg_packet_handshake_send_worker+0x204/0x370 drivers/net/wireguard/send.c:51
process_one_work kernel/workqueue.c:3396 [inline]
process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3479
worker_thread+0xa47/0xfb0 kernel/workqueue.c:3560
kthread+0x38b/0x480 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245