rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6091/1:b..l P5206/1:b..l rcu: (detected by 1, t=10503 jiffies, g=14669, q=1758306 ncpus=2) task:udevd state:R running task stack:23872 pid:5206 tgid:5206 ppid:1 flags:0x00000002 Call Trace: context_switch kernel/sched/core.c:5371 [inline] __schedule+0x189f/0x4c80 kernel/sched/core.c:6758 preempt_schedule_irq+0xfb/0x1c0 kernel/sched/core.c:7080 irqentry_exit+0x5e/0x90 kernel/entry/common.c:354 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:__kernel_text_address+0x26/0x40 kernel/extable.c:79 Code: 90 90 90 90 66 0f 1f 00 53 48 89 fb e8 43 00 00 00 85 c0 0f 95 c0 48 c7 c1 00 b0 7a 91 48 39 cb 0f 93 c1 48 c7 c2 0f b9 95 91 <48> 39 d3 0f 92 c2 20 ca 08 c2 0f b6 c2 5b c3 cc cc cc cc 0f 1f 80 RSP: 0018:ffffc90003907270 EFLAGS: 00000287 RAX: 0000000000000001 RBX: ffffffff823822cc RCX: ffffffff917ab000 RDX: ffffffff9195b90f RSI: ffffc90003900000 RDI: ffffffff823822cc RBP: ffffc90003907330 R08: ffffc90003907c30 R09: 0000000000000000 R10: ffffc900039072f0 R11: fffff52000720e60 R12: ffff88806b66bc00 R13: ffffffff81aae620 R14: dffffc0000000000 R15: 1ffff92000720e5d unwind_get_return_address+0x4d/0x90 arch/x86/kernel/unwind_orc.c:369 arch_stack_walk+0xfd/0x150 arch/x86/kernel/stacktrace.c:26 stack_trace_save+0x118/0x1d0 kernel/stacktrace.c:122 save_stack+0xfb/0x1f0 mm/page_owner.c:156 __reset_page_owner+0x76/0x430 mm/page_owner.c:297 reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1127 [inline] free_frozen_pages+0xe0d/0x10e0 mm/page_alloc.c:2660 discard_slab mm/slub.c:2684 [inline] __put_partials+0x160/0x1c0 mm/slub.c:3153 put_cpu_partial+0x17c/0x250 mm/slub.c:3228 __slab_free+0x290/0x380 mm/slub.c:4479 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x23/0x80 mm/kasan/common.c:329 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4115 [inline] slab_alloc_node mm/slub.c:4164 [inline] __do_kmalloc_node mm/slub.c:4293 [inline] __kmalloc_noprof+0x236/0x4c0 mm/slub.c:4306 kmalloc_noprof include/linux/slab.h:905 [inline] kzalloc_noprof include/linux/slab.h:1037 [inline] tomoyo_encode2 security/tomoyo/realpath.c:45 [inline] tomoyo_encode+0x26f/0x540 security/tomoyo/realpath.c:80 tomoyo_realpath_from_path+0x59e/0x5e0 security/tomoyo/realpath.c:283 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_path_perm+0x2b7/0x740 security/tomoyo/file.c:822 security_inode_getattr+0x130/0x330 security/security.c:2377 vfs_getattr+0x2a/0x3a0 fs/stat.c:243 vfs_statx_path fs/stat.c:283 [inline] vfs_statx+0x18c/0x490 fs/stat.c:347 vfs_fstatat+0xe5/0x130 fs/stat.c:366 __do_sys_newfstatat fs/stat.c:530 [inline] __se_sys_newfstatat fs/stat.c:524 [inline] __x64_sys_newfstatat+0x11d/0x1a0 fs/stat.c:524 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f119fd165f4 RSP: 002b:00007ffec9c11938 EFLAGS: 00000246 ORIG_RAX: 0000000000000106 RAX: ffffffffffffffda RBX: 000055586eb096d8 RCX: 00007f119fd165f4 RDX: 00007ffec9c11948 RSI: 000055586eaf9897 RDI: 00000000ffffff9c RBP: 000055588f6f8c28 R08: 00062a6a1a3814aa R09: 7fffffffffffffff R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000001 R14: 00062a6a1a3814aa R15: 000055586eafddca task:syz.3.33 state:R running task stack:25328 pid:6091 tgid:6079 ppid:5834 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5371 [inline] __schedule+0x189f/0x4c80 kernel/sched/core.c:6758 preempt_schedule_notrace+0x100/0x140 kernel/sched/core.c:7030 preempt_schedule_notrace_thunk+0x1a/0x30 arch/x86/entry/thunk.S:13 rcu_is_watching+0x7e/0xb0 kernel/rcu/tree.c:717 rcu_read_lock include/linux/rcupdate.h:850 [inline] page_ext_get+0x5a/0x2a0 mm/page_ext.c:525 __page_table_check_zero+0xb1/0x350 mm/page_table_check.c:148 page_table_check_free include/linux/page_table_check.h:41 [inline] free_pages_prepare mm/page_alloc.c:1128 [inline] free_frozen_pages+0xe21/0x10e0 mm/page_alloc.c:2660 vfree+0x1c3/0x360 mm/vmalloc.c:3383 kcov_put kernel/kcov.c:439 [inline] kcov_close+0x28/0x50 kernel/kcov.c:535 __fput+0x3e9/0x9f0 fs/file_table.c:450 task_work_run+0x24f/0x310 kernel/task_work.c:227 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0xa2f/0x28e0 kernel/exit.c:938 do_group_exit+0x207/0x2c0 kernel/exit.c:1087 get_signal+0x16b2/0x1750 kernel/signal.c:3017 arch_do_signal_or_restart+0x96/0x860 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop kernel/entry/common.c:111 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0xce/0x340 kernel/entry/common.c:218 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe5e3d85d29 RSP: 002b:00007fe5e4af2038 EFLAGS: 00000246 ORIG_RAX: 0000000000000036 RAX: ffffffffffffff97 RBX: 00007fe5e3f76240 RCX: 00007fe5e3d85d29 RDX: 0000000000000029 RSI: 0000000000000000 RDI: 000000000000000a RBP: 00007fe5e3e01b08 R08: 0000000000000018 R09: 0000000000000000 R10: 0000000020000080 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000001 R14: 00007fe5e3f76240 R15: 00007ffe1fc13248 rcu: rcu_preempt kthread starved for 10584 jiffies! g14669 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:25624 pid:17 tgid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5371 [inline] __schedule+0x189f/0x4c80 kernel/sched/core.c:6758 __schedule_loop kernel/sched/core.c:6835 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6850 schedule_timeout+0x15a/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:2024 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2226 kthread+0x7a9/0x920 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 9 Comm: kworker/0:1 Not tainted 6.13.0-rc3-next-20241220-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Workqueue: events_power_efficient neigh_periodic_work RIP: 0010:skb_reset_mac_header include/linux/skbuff.h:3077 [inline] RIP: 0010:eth_type_trans+0x143/0x7b0 net/ethernet/eth.c:162 Code: 49 81 fc ff ff 00 00 48 89 5c 24 30 0f 87 e2 02 00 00 e8 d0 9f e4 f7 49 8d 9e ba 00 00 00 48 89 d8 48 c1 e8 03 48 89 44 24 20 <42> 0f b6 04 28 84 c0 0f 85 db 03 00 00 66 44 89 23 48 8b 44 24 40 RSP: 0018:ffffc900000069e0 EFLAGS: 00000a06 RAX: 1ffff110439983cf RBX: ffff88821ccc1e7a RCX: ffff88801d2c0000 RDX: 0000000000000100 RSI: 0000000000000132 RDI: 0000000000010000 RBP: ffffc90000006ac8 R08: ffffffff89da8439 R09: 1ffffffff203563e R10: dffffc0000000000 R11: ffffffff86a37c50 R12: 0000000000000132 R13: dffffc0000000000 R14: ffff88821ccc1dc0 R15: ffff88821ccc1e90 FS: 0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c2724d8 CR3: 000000002c220000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: loopback_xmit+0x40b/0x6b0 drivers/net/loopback.c:86 __netdev_start_xmit include/linux/netdevice.h:5049 [inline] netdev_start_xmit include/linux/netdevice.h:5058 [inline] xmit_one net/core/dev.c:3590 [inline] dev_hard_start_xmit+0x27a/0x7d0 net/core/dev.c:3606 __dev_queue_xmit+0x1b73/0x3f50 net/core/dev.c:4434 dev_queue_xmit include/linux/netdevice.h:3212 [inline] neigh_hh_output include/net/neighbour.h:523 [inline] neigh_output include/net/neighbour.h:537 [inline] ip_finish_output2+0xd76/0x12b0 net/ipv4/ip_output.c:236 synproxy_send_client_synack+0x8a4/0xe20 net/netfilter/nf_synproxy_core.c:484 nft_synproxy_eval_v4+0x3ca/0x610 net/netfilter/nft_synproxy.c:59 nft_synproxy_do_eval+0x362/0xa60 net/netfilter/nft_synproxy.c:141 expr_call_ops_eval net/netfilter/nf_tables_core.c:240 [inline] nft_do_chain+0x4ad/0x1da0 net/netfilter/nf_tables_core.c:288 nft_do_chain_inet+0x418/0x6b0 net/netfilter/nft_chain_filter.c:161 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline] nf_hook_slow+0xc3/0x220 net/netfilter/core.c:626 nf_hook include/linux/netfilter.h:269 [inline] NF_HOOK+0x29e/0x450 include/linux/netfilter.h:312 NF_HOOK+0x3a4/0x450 include/linux/netfilter.h:314 __netif_receive_skb_one_core net/core/dev.c:5672 [inline] __netif_receive_skb+0x2bf/0x650 net/core/dev.c:5785 process_backlog+0x662/0x15b0 net/core/dev.c:6117 __napi_poll+0xcb/0x490 net/core/dev.c:6883 napi_poll net/core/dev.c:6952 [inline] net_rx_action+0x89b/0x1240 net/core/dev.c:7074 handle_softirqs+0x2d4/0x9b0 kernel/softirq.c:561 do_softirq+0x11b/0x1e0 kernel/softirq.c:462 __local_bh_enable_ip+0x1bb/0x200 kernel/softirq.c:389 neigh_periodic_work+0xbcb/0xde0 net/core/neighbour.c:968 process_one_work kernel/workqueue.c:3229 [inline] process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3310 worker_thread+0x870/0xd30 kernel/workqueue.c:3391 kthread+0x7a9/0x920 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244