rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P13048/1:b..l P13040/1:b..l rcu: (detected by 0, t=10503 jiffies, g=233669, q=888267 ncpus=2) task:syz.2.9676 state:R running task stack:27200 pid:13040 tgid:13038 ppid:11378 task_flags:0x40054c flags:0x00080001 Call Trace: context_switch kernel/sched/core.c:5533 [inline] __schedule+0x17db/0x58f0 kernel/sched/core.c:7284 preempt_schedule_common+0x7f/0xd0 kernel/sched/core.c:7463 preempt_schedule_thunk+0x16/0x40 arch/x86/entry/thunk.S:12 __local_bh_enable_ip+0xe9/0x140 kernel/softirq.c:480 spin_unlock_bh include/linux/spinlock.h:407 [inline] nl80211_netlink_notify+0x722/0x860 net/wireless/nl80211.c:23180 notifier_call_chain+0x1a5/0x3d0 kernel/notifier.c:85 blocking_notifier_call_chain+0x6a/0x90 kernel/notifier.c:380 netlink_release+0x11fb/0x1a80 net/netlink/af_netlink.c:762 __sock_release+0xa0/0x1f0 net/socket.c:735 sock_close+0x1c/0x30 net/socket.c:1526 __fput+0x418/0xa50 fs/file_table.c:512 task_work_run+0x1d9/0x270 kernel/task_work.c:233 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x73a/0x2360 kernel/exit.c:1012 do_group_exit+0x22d/0x2f0 kernel/exit.c:1155 get_signal+0x121b/0x12c0 kernel/signal.c:3112 arch_do_signal_or_restart+0xbb/0x860 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline] exit_to_user_mode_loop+0x10e/0x770 kernel/entry/common.c:101 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:343 [inline] do_syscall_64+0x328/0x520 arch/x86/entry/syscall_64.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f787339e159 RSP: 002b:00007f78742bf0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007f7873625fa8 RCX: 00007f787339e159 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f7873625fa8 RBP: 00007f7873625fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f7873626038 R14: 00007ffed86a5ce0 R15: 00007ffed86a5dc8 task:syz.0.9677 state:R running task stack:26784 pid:13048 tgid:13045 ppid:11598 task_flags:0x40044c flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5533 [inline] __schedule+0x17db/0x58f0 kernel/sched/core.c:7284 preempt_schedule_common+0x7f/0xd0 kernel/sched/core.c:7463 preempt_schedule_thunk+0x16/0x40 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:201 [inline] _raw_spin_unlock+0x41/0x50 kernel/locking/spinlock.c:213 spin_unlock include/linux/spinlock.h:401 [inline] zap_pte_range mm/memory.c:2095 [inline] zap_pmd_range mm/memory.c:2151 [inline] zap_pud_range mm/memory.c:2179 [inline] zap_p4d_range mm/memory.c:2200 [inline] __zap_vma_range+0x40e1/0x4f80 mm/memory.c:2240 unmap_vmas+0x390/0x550 mm/memory.c:2309 exit_mmap+0x293/0x9f0 mm/mmap.c:1315 __mmput+0x118/0x420 kernel/fork.c:1193 exit_mm+0x221/0x2d0 kernel/exit.c:618 do_exit+0x6cd/0x2360 kernel/exit.c:1000 do_group_exit+0x22d/0x2f0 kernel/exit.c:1155 get_signal+0x121b/0x12c0 kernel/signal.c:3112 arch_do_signal_or_restart+0xbb/0x860 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline] exit_to_user_mode_loop+0x10e/0x770 kernel/entry/common.c:101 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:343 [inline] do_syscall_64+0x328/0x520 arch/x86/entry/syscall_64.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f5946f9e159 RSP: 002b:00007f5947dd70e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007f5947226098 RCX: 00007f5946f9e159 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f5947226098 RBP: 00007f5947226090 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f5947226128 R14: 00007ffe287ebca0 R15: 00007ffe287ebd88 rcu: rcu_preempt kthread starved for 1134 jiffies! g233669 f0x2 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:5533 [inline] __schedule+0x17db/0x58f0 kernel/sched/core.c:7284 __schedule_loop kernel/sched/core.c:7361 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7376 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: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 26824 Comm: kworker/u8:61 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Workqueue: krds_cp_wq#34/0 rds_connect_worker RIP: 0010:debug_lockdep_rcu_enabled+0x16/0x40 kernel/rcu/update.c:320 Code: cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 31 c0 83 3d cb f5 93 04 00 74 1d 83 3d 9a 25 94 04 00 <74> 14 65 48 8b 0d 18 f5 ae 07 31 c0 83 b9 a4 0b 00 00 00 0f 94 c0 RSP: 0018:ffffc90000a177f8 EFLAGS: 00000202 RAX: 0000000000000000 RBX: ffffc90000a178b8 RCX: ffffc90000a17c38 RDX: ffffc90000a17801 RSI: dffffc0000000000 RDI: ffffc90000a178b0 RBP: 1ffffffff2241301 R08: ffffc90000a17c20 R09: 0000000000000000 R10: ffffc90000a178f8 R11: fffff52000142f21 R12: ffffc90000a11000 R13: ffffffff8177f1df R14: ffffc90000a178a8 R15: ffffc90000a17c30 FS: 0000000000000000(0000) GS:ffff888124dca000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000056400e29eed8 CR3: 000000007ebc8000 CR4: 00000000003526f0 Call Trace: rcu_read_unlock include/linux/rcupdate.h:878 [inline] class_rcu_destructor include/linux/rcupdate.h:1216 [inline] unwind_next_frame+0x1b5d/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 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __kmalloc_cache_noprof+0x321/0x600 mm/slub.c:5563 _kmalloc_noprof include/linux/slab.h:991 [inline] _kzalloc_noprof include/linux/slab.h:1312 [inline] ref_tracker_alloc+0x15b/0x4b0 lib/ref_tracker.c:270 __netdev_tracker_alloc include/linux/netdevice.h:4528 [inline] netdev_hold include/linux/netdevice.h:4557 [inline] dst_init+0xbe/0x470 net/core/dst.c:52 dst_alloc+0x12a/0x170 net/core/dst.c:94 rt_dst_alloc net/ipv4/route.c:1681 [inline] __mkroute_output net/ipv4/route.c:2684 [inline] ip_route_output_key_hash_rcu+0x14ac/0x2720 net/ipv4/route.c:2904 ip_route_output_key_hash+0x18d/0x2a0 net/ipv4/route.c:2734 __ip_route_output_key include/net/route.h:169 [inline] ip_route_output_flow+0x2a/0x150 net/ipv4/route.c:2961 ip_route_output_key include/net/route.h:179 [inline] ip_route_me_harder+0x762/0xfe0 net/ipv4/netfilter.c:54 synproxy_send_tcp+0x332/0x670 net/netfilter/nf_synproxy_core.c:434 synproxy_send_client_synack+0x89b/0xde0 net/netfilter/nf_synproxy_core.c:487 nft_synproxy_eval_v4+0x362/0x4e0 net/netfilter/nft_synproxy.c:59 nft_synproxy_do_eval+0x389/0x5d0 net/netfilter/nft_synproxy.c:142 expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline] nft_do_chain+0x48d/0x1b10 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:165 [inline] nf_hook_slow+0xc5/0x220 net/netfilter/core.c:619 nf_hook include/linux/netfilter.h:280 [inline] NF_HOOK+0x21f/0x3c0 include/linux/netfilter.h:323 NF_HOOK+0x336/0x3c0 include/linux/netfilter.h:325 __netif_receive_skb_one_core net/core/dev.c:6265 [inline] __netif_receive_skb net/core/dev.c:6378 [inline] process_backlog+0xa6b/0x18b0 net/core/dev.c:6729 __napi_poll+0xaa/0x330 net/core/dev.c:7798 napi_poll net/core/dev.c:7861 [inline] net_rx_action+0x61d/0xf50 net/core/dev.c:8018 handle_softirqs+0x226/0x860 kernel/softirq.c:645 __do_softirq kernel/softirq.c:679 [inline] invoke_softirq kernel/softirq.c:519 [inline] __irq_exit_rcu+0xcb/0x220 kernel/softirq.c:758 irq_exit_rcu+0x9/0x30 kernel/softirq.c:775 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:on_stack arch/x86/include/asm/stacktrace.h:55 [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+0xb2f/0x2550 arch/x86/kernel/unwind_orc.c:614 Code: b6 72 01 83 e6 07 83 fe 04 0f 84 39 04 00 00 83 fe 03 0f 84 f1 01 00 00 83 fe 02 0f 85 a2 07 00 00 48 89 5c 24 48 49 8d 7e 08 <48> 89 fb 48 c1 eb 03 42 80 3c 23 00 74 09 e8 ce e3 bf 00 4c 8b 04 RSP: 0018:ffffc900053471e0 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffffffff9120a8c3 RCX: ffffffff909d2394 RDX: ffffffff9120a8c2 RSI: 0000000000000002 RDI: ffffc90005347290 RBP: 1ffffffff2241518 R08: ffffc900053476a0 R09: 0000000000000000 R10: ffffc900053472d8 R11: ffffffff81b293f0 R12: dffffc0000000000 R13: ffffffff9120a8be R14: ffffc90005347288 R15: 1ffff92000a68e51 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 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:338 reset_page_owner include/linux/page_owner.h:26 [inline] __free_pages_prepare mm/page_alloc.c:1418 [inline] __free_frozen_pages+0xc93/0xd90 mm/page_alloc.c:2962 __slab_free+0x274/0x2c0 mm/slub.c:5823 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_kmalloc+0x22/0xb0 mm/kasan/common.c:406 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5414 [inline] __kmalloc_noprof+0x36b/0x720 mm/slub.c:5439 _kmalloc_noprof include/linux/slab.h:995 [inline] _kzalloc_noprof include/linux/slab.h:1312 [inline] lsm_blob_alloc security/security.c:218 [inline] lsm_sock_alloc security/security.c:4477 [inline] security_sk_alloc+0x52/0x360 security/security.c:4493 sk_prot_alloc+0x101/0x210 net/core/sock.c:2255 sk_alloc+0x3a/0x390 net/core/sock.c:2308 inet_create+0x7a9/0xff0 net/ipv4/af_inet.c:333 __sock_create+0x4b3/0x9d0 net/socket.c:1676 rds_tcp_conn_path_connect+0x2d8/0x920 net/rds/tcp_connect.c:-1 rds_connect_worker+0x1d8/0x290 net/rds/threads.c:176 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