rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P18684/1:b..l
rcu: (detected by 0, t=10502 jiffies, g=124557, q=4160 ncpus=2)
task:syz.4.5024 state:R running task stack:24600 pid:18684 tgid:18682 ppid:5642 task_flags:0x400040 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5388 [inline]
__schedule+0x1821/0x5740 kernel/sched/core.c:7189
preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7513
irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline]
irqentry_exit+0x14f/0x760 kernel/entry/common.c:164
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:__orc_find arch/x86/kernel/unwind_orc.c:101 [inline]
RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:238 [inline]
RIP: 0010:unwind_next_frame+0x4d6/0x2550 arch/x86/kernel/unwind_orc.c:510
Code: 00 00 83 f8 01 4c 8b 7c 24 50 48 bd 00 00 00 00 00 fc ff df 4c 8b 6c 24 20 0f 84 86 16 00 00 e9 03 02 00 00 49 89 d5 48 89 d5 <48> 89 d8 48 29 e8 48 89 c1 48 c1 f9 02 48 c1 e8 3f 48 01 c8 48 83
RSP: 0018:ffffc900050c74f8 EFLAGS: 00000297
RAX: ffffffff9052ae90 RBX: ffffffff9052ae9c RCX: ffffffff9052ae98
RDX: ffffffff9052ae8c RSI: ffffffff90d327e4 RDI: ffffffff8c28b600
RBP: ffffffff9052ae98 R08: 0000000000000005 R09: ffffffff8e95cca0
R10: ffffc900050c7618 R11: ffffffff81b0f020 R12: ffffffff8230fcfc
R13: ffffffff9052ae94 R14: ffffc900050c75c8 R15: ffffffff9052ae94
arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57
kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556
__call_rcu_common kernel/rcu/tree.c:3131 [inline]
call_rcu+0xee/0x890 kernel/rcu/tree.c:3251
slab_free_hook mm/slub.c:2653 [inline]
slab_free mm/slub.c:6251 [inline]
kmem_cache_free+0x462/0x650 mm/slub.c:6378
__io_req_caches_free+0x1c1/0x270 io_uring/io_uring.c:2152
io_queue_deferred+0x81/0x3e0 io_uring/io_uring.c:461
__io_submit_flush_completions+0xed6/0xff0 io_uring/io_uring.c:1172
io_submit_flush_completions io_uring/io_uring.h:251 [inline]
io_submit_state_end io_uring/io_uring.c:1952 [inline]
io_submit_sqes+0x1cd9/0x22e0 io_uring/io_uring.c:2076
__do_sys_io_uring_enter io_uring/io_uring.c:2651 [inline]
__se_sys_io_uring_enter+0x341/0x1c40 io_uring/io_uring.c:2600
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9e1859ce59
RSP: 002b:00007f9e1943d028 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa
RAX: ffffffffffffffda RBX: 00007f9e18815fa0 RCX: 00007f9e1859ce59
RDX: 00000000ffffffdc RSI: 000000000000012a RDI: 0000000000000000
RBP: 00007f9e18632d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000017 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9e18816038 R14: 00007f9e18815fa0 R15: 00007f9e1893fa48
rcu: rcu_preempt kthread starved for 724 jiffies! g124557 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:27536 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5388 [inline]
__schedule+0x1821/0x5740 kernel/sched/core.c:7189
__schedule_loop kernel/sched/core.c:7268 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7283
schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x312/0x11d0 kernel/rcu/tree.c:2095
rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2297
kthread+0x389/0x470 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:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 12 Comm: kworker/u8:0 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Workqueue: events_unbound nsim_dev_trap_report_work
RIP: 0010:lockdep_recursion_finish kernel/locking/lockdep.c:470 [inline]
RIP: 0010:lock_release+0x259/0x3c0 kernel/locking/lockdep.c:5891
Code: 41 8d 45 ff 41 89 c5 7f d0 4c 89 ff 4c 89 f6 48 8b 54 24 18 e8 28 2f 00 00 48 8b 5c 24 08 48 c7 c7 29 04 22 8e e8 27 89 07 0a ff ff ff ff 65 0f c1 05 3a ed 97 11 83 f8 01 75 2e 9c 58 a9 00
RSP: 0018:ffffc90000a07d10 EFLAGS: 00000002
RAX: 0000000000000001 RBX: 0000000000000202 RCX: 0000000080000102
RDX: 0000000000000006 RSI: ffffffff8e220429 RDI: ffffffff8c28b660
RBP: ffff88801da80c80 R08: ffffc90000a07ea7 R09: 0000000000000000
R10: ffffc90000a07e98 R11: fffff52000140fd5 R12: 0000000000000006
R13: 0000000000000006 R14: ffffffff8e95cca0 R15: ffff88801da80000
FS: 0000000000000000(0000) GS:ffff888125387000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fdc3c5f5ff8 CR3: 000000007c972000 CR4: 00000000003526f0
Call Trace:
rcu_lock_release include/linux/rcupdate.h:310 [inline]
rcu_read_unlock include/linux/rcupdate.h:869 [inline]
class_rcu_destructor include/linux/rcupdate.h:1181 [inline]
unwind_next_frame+0x1bba/0x2550 arch/x86/kernel/unwind_orc.c:709
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:4570 [inline]
slab_alloc_node mm/slub.c:4899 [inline]
kmem_cache_alloc_node_noprof+0x384/0x690 mm/slub.c:4951
__alloc_skb+0x1d0/0x7d0 net/core/skbuff.c:702
alloc_skb include/linux/skbuff.h:1383 [inline]
synproxy_send_client_synack+0x172/0xe30 net/netfilter/nf_synproxy_core.c:461
nft_synproxy_eval_v4+0x34a/0x4e0 net/netfilter/nft_synproxy.c:60
nft_synproxy_do_eval+0x305/0x580 net/netfilter/nft_synproxy.c:142
expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline]
nft_do_chain+0x48d/0x1ae0 net/netfilter/nf_tables_core.c:285
nft_do_chain_inet+0x360/0x4b0 net/netfilter/nft_chain_filter.c:162
nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline]
nf_hook_slow+0xc5/0x220 net/netfilter/core.c:619
nf_hook include/linux/netfilter.h:273 [inline]
NF_HOOK+0x21f/0x3c0 include/linux/netfilter.h:316
NF_HOOK+0x336/0x3c0 include/linux/netfilter.h:318
__netif_receive_skb_one_core net/core/dev.c:6202 [inline]
__netif_receive_skb net/core/dev.c:6315 [inline]
process_backlog+0xaa3/0x1950 net/core/dev.c:6666
__napi_poll+0xae/0x340 net/core/dev.c:7733
napi_poll net/core/dev.c:7796 [inline]
net_rx_action+0x627/0xf70 net/core/dev.c:7953
handle_softirqs+0x22a/0x840 kernel/softirq.c:622
do_softirq+0x76/0xd0 kernel/softirq.c:523
__local_bh_enable_ip+0xf8/0x130 kernel/softirq.c:450
spin_unlock_bh include/linux/spinlock.h:396 [inline]
nsim_dev_trap_report drivers/net/netdevsim/dev.c:891 [inline]
nsim_dev_trap_report_work+0x7d6/0xb90 drivers/net/netdevsim/dev.c:922
process_one_work kernel/workqueue.c:3314 [inline]
process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3397
worker_thread+0xa53/0xfc0 kernel/workqueue.c:3478
kthread+0x389/0x470 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