rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4977/1:b..l
rcu: (detected by 1, t=10503 jiffies, g=250573, q=306 ncpus=2)
task:klogd state:R running task stack:23400 pid:4977 tgid:4977 ppid:1 task_flags:0x400100 flags:0x00080800
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x17d9/0x56c0 kernel/sched/core.c:7234
preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7556
irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline]
irqentry_exit+0x14f/0x8f0 kernel/entry/common.c:167
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:stack_access_ok arch/x86/kernel/unwind_orc.c:409 [inline]
RIP: 0010:deref_stack_reg arch/x86/kernel/unwind_orc.c:419 [inline]
RIP: 0010:unwind_next_frame+0xb64/0x2550 arch/x86/kernel/unwind_orc.c:614
Code: 00 74 09 e8 5e 0e bd 00 4c 8b 04 24 4d 8b 7e 08 49 8d 7e 10 49 89 fc 49 c1 ec 03 48 b8 00 00 00 00 00 fc ff df 41 80 3c 04 00 <74> 09 e8 35 0e bd 00 4c 8b 04 24 49 8d 50 f8 4d 8b 6e 10 48 b8 00
RSP: 0018:ffffc90004b8f2c0 EFLAGS: 00000246
RAX: dffffc0000000000 RBX: 1ffff92000971e6e RCX: ffffffff90cc69ac
RDX: ffffffff91780eb2 RSI: 0000000000000002 RDI: ffffc90004b8f378
RBP: 1ffffffff22f01d6 R08: ffffc90004b8f920 R09: 0000000000000000
R10: 0000000000000000 R11: ffffffff8eb59c60 R12: 1ffff92000971e6f
R13: ffffffff91780eae R14: ffffc90004b8f368 R15: ffffc90004b88000
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:165
__reset_page_owner+0x71/0x1f0 mm/page_owner.c:320
reset_page_owner include/linux/page_owner.h:25 [inline]
__free_pages_prepare mm/page_alloc.c:1406 [inline]
__free_frozen_pages+0xc1e/0xd10 mm/page_alloc.c:2950
__slab_free+0x274/0x2c0 mm/slub.c:5741
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x99/0x100 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350
kasan_slab_alloc include/linux/kasan.h:253 [inline]
slab_post_alloc_hook mm/slub.c:4584 [inline]
slab_alloc_node mm/slub.c:4917 [inline]
__do_kmalloc_node mm/slub.c:5333 [inline]
__kmalloc_node_track_caller_noprof+0x461/0x730 mm/slub.c:5471
kmalloc_reserve net/core/skbuff.c:637 [inline]
__alloc_skb+0x2bd/0x7a0 net/core/skbuff.c:715
alloc_skb include/linux/skbuff.h:1384 [inline]
alloc_skb_with_frags+0xc6/0x760 net/core/skbuff.c:6775
sock_alloc_send_pskb+0x878/0x990 net/core/sock.c:3013
unix_dgram_sendmsg+0x4da/0x17b0 net/unix/af_unix.c:2137
sock_sendmsg_nosec+0x13a/0x180 net/socket.c:775
__sock_sendmsg net/socket.c:790 [inline]
__sys_sendto+0x408/0x5a0 net/socket.c:2252
__do_sys_sendto net/socket.c:2259 [inline]
__se_sys_sendto net/socket.c:2255 [inline]
__x64_sys_sendto+0xde/0x100 net/socket.c:2255
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f483e876407
RSP: 002b:00007ffd86fecce0 EFLAGS: 00000202 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f483e726c80 RCX: 00007f483e876407
RDX: 00000000000000a0 RSI: 00007ffd86fece20 RDI: 0000000000000003
RBP: 00007ffd86fed250 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000004000 R11: 0000000000000202 R12: 00007ffd86fed268
R13: 00007ffd86fece20 R14: 0000000000000085 R15: 00007ffd86fece20
rcu: rcu_preempt kthread starved for 6913 jiffies! g250573 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x17d9/0x56c0 kernel/sched/core.c:7234
__schedule_loop kernel/sched/core.c:7311 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7326
schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x30c/0x11f0 kernel/rcu/tree.c:2123
rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2325
kthread+0x388/0x470 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: 6167 Comm: kworker/1:7 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Workqueue: events_power_efficient neigh_periodic_work
RIP: 0010:trace_lock_acquire include/trace/events/lock.h:23 [inline]
RIP: 0010:lock_acquire+0x61/0x350 kernel/locking/lockdep.c:5831
Code: 24 58 0f 1f 44 00 00 65 8b 05 bf 89 ca 11 83 f8 08 0f 83 83 01 00 00 89 c0 48 0f a3 05 a8 d6 b4 0e 73 0d e8 f1 29 09 00 84 c0 <0f> 84 ca 01 00 00 83 3d a2 09 b5 0e 00 0f 84 d3 00 00 00 48 8b b4
RSP: 0018:ffffc90000a07d20 EFLAGS: 00000202
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000000000102
RDX: 0000000000000000 RSI: ffffffff8c4bdd60 RDI: ffffffff8c4bdd20
RBP: ffffffff8177927f R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffffff81b20c80 R12: 0000000000000002
R13: ffffffff8eb59c60 R14: 0000000000000000 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff88812504b000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055556b9aa4e8 CR3: 0000000074fd3000 CR4: 0000000000350ef0
Call Trace:
rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
rcu_read_lock include/linux/rcupdate.h:840 [inline]
class_rcu_constructor include/linux/rcupdate.h:1183 [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
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
unpoison_slab_object mm/kasan/common.c:340 [inline]
__kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366
kasan_slab_alloc include/linux/kasan.h:253 [inline]
slab_post_alloc_hook mm/slub.c:4584 [inline]
slab_alloc_node mm/slub.c:4917 [inline]
kmem_cache_alloc_node_noprof+0x355/0x610 mm/slub.c:4989
__alloc_skb+0x1d7/0x7a0 net/core/skbuff.c:704
alloc_skb include/linux/skbuff.h:1384 [inline]
nlmsg_new include/net/netlink.h:1055 [inline]
fdb_notify+0xa6/0x160 net/bridge/br_fdb.c:188
br_fdb_update+0x4e6/0x6c0 net/bridge/br_fdb.c:1024
br_handle_frame_finish+0x618/0x1990 net/bridge/br_input.c:144
br_nf_hook_thresh+0x3dd/0x4c0 net/bridge/br_netfilter_hooks.c:-1
br_nf_pre_routing_finish_ipv6+0x90c/0xc40 net/bridge/br_netfilter_ipv6.c:-1
NF_HOOK include/linux/netfilter.h:318 [inline]
br_nf_pre_routing_ipv6+0x382/0x6f0 net/bridge/br_netfilter_ipv6.c:183
nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline]
nf_hook_bridge_pre net/bridge/br_input.c:291 [inline]
br_handle_frame+0x127f/0x1510 net/bridge/br_input.c:442
__netif_receive_skb_core+0x989/0x30b0 net/core/dev.c:6099
__netif_receive_skb_one_core net/core/dev.c:6210 [inline]
__netif_receive_skb net/core/dev.c:6325 [inline]
process_backlog+0x706/0x1860 net/core/dev.c:6676
__napi_poll+0xaa/0x330 net/core/dev.c:7735
napi_poll net/core/dev.c:7798 [inline]
net_rx_action+0x61d/0xf50 net/core/dev.c:7955
handle_softirqs+0x225/0x840 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0xca/0x220 kernel/softirq.c:735
irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1062
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:preempt_schedule_irq+0x48/0xa0 kernel/sched/core.c:7556
Code: 49 be 00 00 00 00 00 fc ff df eb 09 48 f7 03 10 00 00 00 74 53 bf 01 00 00 00 e8 63 12 c2 f5 e8 fe e0 fc f5 fb bf 01 00 00 00 83 a3 ff ff 9c 58 fa a9 00 02 00 00 74 05 e8 c4 e2 fc f5 bf 01
RSP: 0018:ffffc90003f8f948 EFLAGS: 00000202
RAX: 0000000002b83bb3 RBX: 0000000000000000 RCX: 0000000000000001
RDX: 0000000000000006 RSI: ffffffff8e22f174 RDI: 0000000000000001
RBP: 0000000000000000 R08: ffffffff90579d37 R09: 1ffffffff20af3a6
R10: dffffc0000000000 R11: fffffbfff20af3a7 R12: 0000000000000000
R13: 0000000000000000 R14: dffffc0000000000 R15: 0000000000000000
irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline]
irqentry_exit+0x14f/0x8f0 kernel/entry/common.c:167
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:should_resched arch/x86/include/asm/preempt.h:104 [inline]
RIP: 0010:__local_bh_enable_ip+0xd8/0x130 kernel/softirq.c:457
Code: 8b e8 8c c3 48 0a 65 66 8b 05 9c c0 e4 11 66 85 c0 75 32 bf 01 00 00 00 e8 85 f0 0b 00 e8 80 bd 46 00 fb 65 8b 05 78 c0 e4 11 <85> c0 75 05 e8 3f df aa ff 5b 41 5e e9 42 b1 87 ff cc 90 0f 0b 90
RSP: 0018:ffffc90003f8fa68 EFLAGS: 00000206
RAX: 0000000080000000 RBX: 0000000000000201 RCX: 0000000000000046
RDX: 0000000000000006 RSI: ffffffff8e22f174 RDI: ffffffff8c4bdd80
RBP: 0000000000000000 R08: ffffffff90579d37 R09: 1ffffffff20af3a6
R10: dffffc0000000000 R11: fffffbfff20af3a7 R12: ffff888020fe5b00
R13: 0000000000000000 R14: ffffffff89a7cee3 R15: ffff88802a469af0
spin_unlock_bh include/linux/spinlock.h:396 [inline]
neigh_periodic_work+0xc23/0xe40 net/core/neighbour.c:1035
process_one_work kernel/workqueue.c:3322 [inline]
process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405
worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486
kthread+0x388/0x470 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