rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4376/1:b..l rcu: (detected by 0, t=10502 jiffies, g=31457, q=2182 ncpus=1) task:udevd state:R running task stack:0 pid:4376 tgid:4376 ppid:1 task_flags:0x400140 flags:0x00000000 Call trace: __switch_to+0x2b4/0x6e4 arch/arm64/kernel/process.c:775 (T) context_switch kernel/sched/core.c:5533 [inline] __schedule+0x135c/0x2b00 kernel/sched/core.c:7284 preempt_schedule_irq+0x74/0x174 kernel/sched/core.c:7606 raw_irqentry_exit_cond_resched+0x30/0x40 kernel/entry/common.c:145 irqentry_exit_to_kernel_mode_preempt+0x44/0x54 include/linux/irq-entry-common.h:468 arm64_exit_to_kernel_mode_preempt+0x1c/0x38 arch/arm64/kernel/entry-common.c:107 __el1_irq arch/arm64/kernel/entry-common.c:571 [inline] el1_interrupt+0x4c/0x60 arch/arm64/kernel/entry-common.c:581 el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:586 el1h_64_irq+0x78/0x7c arch/arm64/kernel/entry.S:602 bytes_is_nonzero mm/kasan/generic.c:98 [inline] (P) memory_is_nonzero mm/kasan/generic.c:115 [inline] (P) memory_is_poisoned_n mm/kasan/generic.c:140 [inline] (P) memory_is_poisoned mm/kasan/generic.c:172 [inline] (P) check_region_inline mm/kasan/generic.c:191 [inline] (P) kasan_check_range+0x7c/0x1ac mm/kasan/generic.c:200 (P) __kasan_check_read+0x20/0x30 mm/kasan/shadow.c:31 instrument_atomic_read include/linux/instrumented.h:82 [inline] atomic_read include/linux/atomic/atomic-instrumented.h:32 [inline] __page_table_check_zero+0x1d0/0x40c mm/page_table_check.c:142 page_table_check_free include/linux/page_table_check.h:46 [inline] __free_pages_prepare mm/page_alloc.c:1419 [inline] __free_frozen_pages+0xb00/0xbd0 mm/page_alloc.c:2962 free_frozen_pages+0x14/0x20 mm/page_alloc.c:2999 __free_slab+0x11c/0x1b4 mm/slub.c:3528 free_slab+0x2c/0x154 mm/slub.c:3562 discard_slab+0x48/0x90 mm/slub.c:3568 __slab_free+0x1a0/0x1d0 mm/slub.c:5823 ___cache_free+0x80/0x94 mm/slub.c:6581 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0xb4/0x120 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x118/0x124 mm/kasan/quarantine.c:286 __kasan_kmalloc+0x2c/0xb4 mm/kasan/common.c:417 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5414 [inline] __kmalloc_noprof+0x34c/0x6c8 mm/slub.c:5439 _kmalloc_noprof include/linux/slab.h:995 [inline] _kzalloc_noprof include/linux/slab.h:1312 [inline] tomoyo_encode2+0x10c/0x330 security/tomoyo/realpath.c:45 tomoyo_encode+0x34/0x50 security/tomoyo/realpath.c:80 tomoyo_realpath_from_path+0x488/0x4dc security/tomoyo/realpath.c:283 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_path_perm+0x218/0x460 security/tomoyo/file.c:827 tomoyo_inode_getattr+0x28/0x38 security/tomoyo/tomoyo.c:123 security_inode_getattr+0x114/0x2c0 security/security.c:1895 vfs_getattr fs/stat.c:259 [inline] vfs_statx_path+0x34/0x22c fs/stat.c:299 vfs_statx+0x124/0x1d8 fs/stat.c:356 vfs_fstatat+0xa4/0xd0 fs/stat.c:373 __do_sys_newfstatat fs/stat.c:538 [inline] __se_sys_newfstatat fs/stat.c:532 [inline] __arm64_sys_newfstatat+0x134/0x1c8 fs/stat.c:532 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xec/0x23c arch/arm64/kernel/syscall.c:121 do_el0_svc+0x4c/0x5c arch/arm64/kernel/syscall.c:140 el0_svc+0x60/0x1d8 arch/arm64/kernel/entry-common.c:796 el0t_64_sync_handler+0x44/0x104 arch/arm64/kernel/entry-common.c:815 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:606 rcu: rcu_preempt kthread starved for 288 jiffies! g31457 f0x0 RCU_GP_WAIT_FQS(5) ->state=R ->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:R running task stack:0 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00000010 Call trace: __switch_to+0x2b4/0x6e4 arch/arm64/kernel/process.c:775 (T) context_switch kernel/sched/core.c:5533 [inline] __schedule+0x135c/0x2b00 kernel/sched/core.c:7284 __schedule_loop kernel/sched/core.c:7361 [inline] schedule+0x13c/0x20c kernel/sched/core.c:7376 schedule_timeout+0x13c/0x28c kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x260/0xde8 kernel/rcu/tree.c:2122 rcu_gp_kthread+0x148/0x230 kernel/rcu/tree.c:2330 kthread+0x304/0x3d4 kernel/kthread.c:436 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:854 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 UID: 0 PID: 1945 Comm: kworker/u8:11 Tainted: G L syzkaller #0 PREEMPT Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/23/2026 Workqueue: events_unbound cfg80211_wiphy_work pstate: 03400005 (nzcv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=--) pc : in_softirq_really kernel/kcov.c:167 [inline] pc : check_kcov_mode+0x18/0x54 kernel/kcov.c:179 lr : write_comp_data+0x38/0x84 kernel/kcov.c:242 sp : ffff80008f856e90 x29: ffff80008f856e90 x28: ffff0000f3275490 x27: 1fffe0001e64ea80 x26: dfff800000000000 x25: 0000000000000001 x24: ffff80008ab74e40 x23: ffff0000cafe0000 x22: 0000000000000001 x21: 0000000000000000 x20: 0000000000000001 x19: ffff80008503d05c x18: ffff8001237ae000 x17: ffff0001acf6ce07 x16: 00000000002b9a91 x15: 00000000002b9a92 x14: 0000000000c032ec x13: 0000000000000004 x12: 0000000000000003 x11: ffff700011f0adc4 x10: 000000000000000f x9 : 0000000000000101 x8 : ffff0000cafe0000 x7 : 0000000000000000 x6 : 0000000000000000 x5 : 0000000000000001 x4 : 0000000000000008 x3 : ffff80008503d05c x2 : 0000000000000001 x1 : ffff0000cafe0000 x0 : 0000000000000003 Call trace: preempt_count arch/arm64/include/asm/preempt.h:12 [inline] (P) in_softirq_really kernel/kcov.c:167 [inline] (P) check_kcov_mode+0x18/0x54 kernel/kcov.c:179 (P) __sanitizer_cov_trace_switch+0x74/0x94 kernel/kcov.c:347 nf_hook_slow+0xd8/0x224 net/netfilter/core.c:620 nf_hook+0x1f0/0x364 include/linux/netfilter.h:280 __ip_local_out+0x4e8/0x5c8 net/ipv4/ip_output.c:120 ip_local_out+0x3c/0x148 net/ipv4/ip_output.c:129 synproxy_send_tcp+0x3ec/0x5a4 net/netfilter/nf_synproxy_core.c:442 synproxy_send_client_synack+0x3b0/0x640 net/netfilter/nf_synproxy_core.c:487 nft_synproxy_eval_v4+0x16c/0x278 net/netfilter/nft_synproxy.c:59 nft_synproxy_do_eval+0x2e8/0x4dc net/netfilter/nft_synproxy.c:142 nft_synproxy_eval+0x34/0x48 net/netfilter/nft_synproxy.c:248 expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline] nft_do_chain+0x418/0x13c8 net/netfilter/nf_tables_core.c:285 nft_do_chain_inet+0x284/0x3d4 net/netfilter/nft_chain_filter.c:162 nf_hook_entry_hookfn include/linux/netfilter.h:165 [inline] nf_hook_slow+0xc8/0x224 net/netfilter/core.c:619 nf_hook include/linux/netfilter.h:280 [inline] NF_HOOK+0x1f0/0x398 include/linux/netfilter.h:323 ip_local_deliver+0x128/0x188 net/ipv4/ip_input.c:262 dst_input include/net/dst.h:481 [inline] ip_rcv_finish+0x20c/0x230 net/ipv4/ip_input.c:492 NF_HOOK+0x308/0x398 include/linux/netfilter.h:325 ip_rcv+0x7c/0x9c net/ipv4/ip_input.c:612 __netif_receive_skb_one_core+0xc8/0x110 net/core/dev.c:6297 __netif_receive_skb+0x34/0x128 net/core/dev.c:6410 process_backlog+0x588/0x14e0 net/core/dev.c:6761 __napi_poll+0xb4/0x328 net/core/dev.c:7830 napi_poll net/core/dev.c:7893 [inline] net_rx_action+0x5b0/0xc14 net/core/dev.c:8050 handle_softirqs+0x324/0xcbc kernel/softirq.c:645 __do_softirq+0x14/0x20 kernel/softirq.c:679 ____do_softirq+0x10/0x1c arch/arm64/kernel/irq.c:78 call_on_irq_stack+0x30/0x48 arch/arm64/kernel/entry.S:901 do_softirq_own_stack+0x1c/0x28 arch/arm64/kernel/irq.c:83 do_softirq+0x90/0xf8 kernel/softirq.c:546 __local_bh_enable_ip+0x190/0x234 kernel/softirq.c:473 __raw_spin_unlock_bh include/linux/spinlock_api_smp.h:237 [inline] _raw_spin_unlock_bh+0x3c/0x4c kernel/locking/spinlock.c:245 spin_unlock_bh include/linux/spinlock.h:407 [inline] cfg80211_inform_single_bss_data+0x1048/0x17a0 net/wireless/scan.c:2462 cfg80211_inform_bss_data+0x1ec/0x2d04 net/wireless/scan.c:3302 cfg80211_inform_bss_frame_data+0x348/0x714 net/wireless/scan.c:3394 ieee80211_bss_info_update+0x5d0/0x944 net/mac80211/scan.c:230 ieee80211_rx_bss_info net/mac80211/ibss.c:1065 [inline] ieee80211_rx_mgmt_probe_beacon net/mac80211/ibss.c:1546 [inline] ieee80211_ibss_rx_queued_mgmt+0x830/0x242c net/mac80211/ibss.c:1573 ieee80211_iface_process_skb net/mac80211/iface.c:1809 [inline] ieee80211_iface_work+0x600/0xd3c net/mac80211/iface.c:1863 cfg80211_wiphy_work+0x278/0x464 net/wireless/core.c:564 process_one_work kernel/workqueue.c:3396 [inline] process_scheduled_works+0x91c/0x1250 kernel/workqueue.c:3479 worker_thread+0x798/0xbd0 kernel/workqueue.c:3560 kthread+0x304/0x3d4 kernel/kthread.c:436 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:854