rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5613/1:b..l.. P9813/1:b..l.. P5600/3:b..l.. P10521/1:b..l.. rcu: (detected by 0, t=10502 jiffies, g=168333, q=854805 ncpus=1) task:syz-executor state:R running task stack:22288 pid:10521 tgid:10521 ppid:1 task_flags:0x40054c flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5583 [inline] __schedule+0x17dd/0x5830 kernel/sched/core.c:7382 preempt_schedule_common+0x7f/0xd0 kernel/sched/core.c:7561 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:2058 [inline] zap_pmd_range mm/memory.c:2113 [inline] zap_pud_range mm/memory.c:2141 [inline] zap_p4d_range mm/memory.c:2162 [inline] __zap_vma_range+0x3d29/0x4b50 mm/memory.c:2202 unmap_vmas+0x38b/0x550 mm/memory.c:2271 exit_mmap+0x290/0xa40 mm/mmap.c:1315 __mmput+0x118/0x420 kernel/fork.c:1192 exit_mm+0x18e/0x240 kernel/exit.c:586 do_exit+0x6a8/0x2360 kernel/exit.c:967 do_group_exit+0x22d/0x2f0 kernel/exit.c:1123 get_signal+0x1216/0x12c0 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: 0033:0x7f70c819e87c RSP: 002b:00007ffc1381fd70 EFLAGS: 00000206 ORIG_RAX: 0000000000000101 RAX: 0000000000000003 RBX: 000000000000018a RCX: 00007f70c819e87c RDX: 0000000000090800 RSI: 00007f70c8236455 RDI: 00000000ffffff9c RBP: 00007ffc1381fe1c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 000000000000007b R13: 0000000000000000 R14: 000000000006d7ea R15: 00007ffc1381fe70 task:syz-executor state:R running task stack:22184 pid:5600 tgid:5600 ppid:5599 task_flags:0x400100 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5583 [inline] __schedule+0x17dd/0x5830 kernel/sched/core.c:7382 preempt_schedule_common+0x7f/0xd0 kernel/sched/core.c:7561 preempt_schedule_thunk+0x16/0x40 arch/x86/entry/thunk.S:12 __local_bh_enable_ip+0xe9/0x140 kernel/softirq.c:480 local_bh_enable include/linux/bottom_half.h:33 [inline] rcu_read_unlock_bh include/linux/rcupdate.h:923 [inline] __dev_queue_xmit+0x1efb/0x3920 net/core/dev.c:5101 dev_queue_xmit include/linux/netdevice.h:3483 [inline] neigh_hh_output include/net/neighbour.h:538 [inline] neigh_output include/net/neighbour.h:552 [inline] ip_finish_output2+0xbda/0x10b0 net/ipv4/ip_output.c:236 NF_HOOK_COND include/linux/netfilter.h:314 [inline] ip_output+0x29f/0x450 net/ipv4/ip_output.c:437 __ip_queue_xmit+0x10df/0x1b10 net/ipv4/ip_output.c:533 __tcp_transmit_skb+0x2d06/0x47b0 net/ipv4/tcp_output.c:1773 tcp_transmit_skb net/ipv4/tcp_output.c:1790 [inline] tcp_write_xmit+0x1cdf/0x6550 net/ipv4/tcp_output.c:3126 __tcp_push_pending_frames+0x96/0x380 net/ipv4/tcp_output.c:3309 tcp_sendmsg_locked+0x472e/0x5320 net/ipv4/tcp.c:1417 tcp_sendmsg+0x2f/0x50 net/ipv4/tcp.c:1454 sock_sendmsg_nosec+0x10f/0x190 net/socket.c:801 __sock_sendmsg net/socket.c:818 [inline] sock_write_iter+0x2de/0x3e0 net/socket.c:1269 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x612/0xba0 fs/read_write.c:687 ksys_write+0x150/0x270 fs/read_write.c:1036 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f8a0195a6d7 RSP: 002b:00007ffc474aaf00 EFLAGS: 00000202 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000555582cd8540 RCX: 00007f8a0195a6d7 RDX: 0000000000000218 RSI: 00007f89fe9ffde8 RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000218 R13: 0000555582cec710 R14: 00007ffc474ab4e0 R15: 00007f89fe9ffde8 task:syz-executor state:R running task stack:22280 pid:9813 tgid:9813 ppid:9808 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5583 [inline] __schedule+0x17dd/0x5830 kernel/sched/core.c:7382 preempt_schedule_irq+0x4b/0x90 kernel/sched/core.c:7662 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:543 [inline] irqentry_exit+0x14f/0x9b0 kernel/entry/common.c:154 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:lock_acquire+0x232/0x350 kernel/locking/lockdep.c:5947 Code: ff ff ff e8 a0 23 6a 0a f7 44 24 10 00 02 00 00 0f 84 38 ff ff ff 65 48 8b 05 a2 bd 40 13 48 3b 44 24 50 75 33 fb 48 83 c4 58 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 bf 36 6d 0a cc 48 8d 3d 07 4c 1d RSP: 0018:ffffc90003b8f160 EFLAGS: 00000296 RAX: 64d16995f8837700 RBX: 0000000000000000 RCX: 0000000000000046 RDX: 00000000ced074c7 RSI: ffffffff8ea4b2ee RDI: ffffffff8c8fe680 RBP: ffff888028671f40 R08: ffffffff8178898f R09: 0000000000000000 R10: ffffc90003b8f298 R11: ffffffff81b3bd40 R12: ffffffff9015a4a0 R13: 0000000000000002 R14: 0000000000000000 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:309 [inline] rcu_read_lock include/linux/rcupdate.h:849 [inline] class_rcu_constructor include/linux/rcupdate.h:1216 [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 save_stack+0x122/0x230 mm/page_owner.c:183 __reset_page_owner+0x73/0x2a0 mm/page_owner.c:338 reset_page_owner include/linux/page_owner.h:26 [inline] __free_pages_prepare mm/page_alloc.c:1403 [inline] __free_frozen_pages+0xc97/0xd90 mm/page_alloc.c:2954 __slab_free+0x269/0x2c0 mm/slub.c:5926 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:417 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5531 [inline] __kmalloc_noprof+0x366/0x710 mm/slub.c:5556 _kmalloc_noprof include/linux/slab.h:995 [inline] tomoyo_realpath_from_path+0xef/0x640 security/tomoyo/realpath.c:251 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_check_open_permission+0x229/0x470 security/tomoyo/file.c:776 security_file_open+0xa9/0x240 security/security.c:2760 do_dentry_open+0x495/0x1360 fs/open.c:977 vfs_open_consume+0x4a/0x350 fs/open.c:1131 do_open fs/namei.c:4845 [inline] path_openat+0x16fc/0x20f0 fs/namei.c:5010 do_file_open+0x23e/0x4a0 fs/namei.c:5039 do_sys_openat2+0x115/0x200 fs/open.c:1442 do_sys_open fs/open.c:1448 [inline] __do_sys_openat fs/open.c:1788 [inline] __se_sys_openat fs/open.c:1783 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1783 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fde9fb9e87c RSP: 002b:00007ffed94c8720 EFLAGS: 00000206 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 0000000000000250 RCX: 00007fde9fb9e87c RDX: 0000000000090800 RSI: 00007fde9fc36455 RDI: 00000000ffffff9c RBP: 00007ffed94c87cc R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 00000000000000bf R13: 0000000000000000 R14: 000000000006d21f R15: 00007ffed94c8820 task:syz-executor state:R running task stack:21344 pid:5613 tgid:5613 ppid:5607 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5583 [inline] __schedule+0x17dd/0x5830 kernel/sched/core.c:7382 preempt_schedule_irq+0x4b/0x90 kernel/sched/core.c:7662 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:543 [inline] irqentry_exit+0x14f/0x9b0 kernel/entry/common.c:154 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:lock_acquire+0x232/0x350 kernel/locking/lockdep.c:5947 Code: ff ff ff e8 a0 23 6a 0a f7 44 24 10 00 02 00 00 0f 84 38 ff ff ff 65 48 8b 05 a2 bd 40 13 48 3b 44 24 50 75 33 fb 48 83 c4 58 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 bf 36 6d 0a cc 48 8d 3d 07 4c 1d RSP: 0018:ffffc90003e8f120 EFLAGS: 00000292 RAX: d829aba18abaae00 RBX: 0000000000000000 RCX: 0000000000000046 RDX: 00000000ced074c7 RSI: ffffffff8ea4b2ee RDI: ffffffff8c8fe680 RBP: ffff8880768bbe80 R08: ffffffff8178898f R09: 0000000000000000 R10: ffffc90003e8f258 R11: ffffffff81b3bd40 R12: ffffffff9015a4a0 R13: 0000000000000002 R14: 0000000000000000 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:309 [inline] rcu_read_lock include/linux/rcupdate.h:849 [inline] class_rcu_constructor include/linux/rcupdate.h:1216 [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 save_stack+0x122/0x230 mm/page_owner.c:183 __reset_page_owner+0x73/0x2a0 mm/page_owner.c:338 reset_page_owner include/linux/page_owner.h:26 [inline] __free_pages_prepare mm/page_alloc.c:1403 [inline] __free_frozen_pages+0xc97/0xd90 mm/page_alloc.c:2954 __slab_free+0x269/0x2c0 mm/slub.c:5926 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:417 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5531 [inline] __kmalloc_noprof+0x366/0x710 mm/slub.c:5556 _kmalloc_noprof include/linux/slab.h:995 [inline] _kzalloc_noprof include/linux/slab.h:1312 [inline] tomoyo_encode2 security/tomoyo/realpath.c:45 [inline] tomoyo_encode+0x2ad/0x570 security/tomoyo/realpath.c:80 tomoyo_realpath_from_path+0x5fa/0x640 security/tomoyo/realpath.c:283 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_check_open_permission+0x229/0x470 security/tomoyo/file.c:776 security_file_open+0xa9/0x240 security/security.c:2760 do_dentry_open+0x495/0x1360 fs/open.c:977 vfs_open_consume+0x4a/0x350 fs/open.c:1131 do_open fs/namei.c:4845 [inline] path_openat+0x16fc/0x20f0 fs/namei.c:5010 do_file_open+0x23e/0x4a0 fs/namei.c:5039 do_sys_openat2+0x115/0x200 fs/open.c:1442 do_sys_open fs/open.c:1448 [inline] __do_sys_openat fs/open.c:1788 [inline] __se_sys_openat fs/open.c:1783 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1783 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fea6919e87c RSP: 002b:00007ffd984b0d20 EFLAGS: 00000206 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00000000000004cb RCX: 00007fea6919e87c RDX: 0000000000090800 RSI: 00007fea69236455 RDI: 00000000ffffff9c RBP: 00007ffd984b0dcc R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 000000000000019d R13: 0000000000000000 R14: 000000000006cec1 R15: 00007ffd984b0e20 rcu: rcu_preempt kthread starved for 630 jiffies! g168333 f0x2 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:27488 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5583 [inline] __schedule+0x17dd/0x5830 kernel/sched/core.c:7382 __schedule_loop kernel/sched/core.c:7459 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7474 schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x30c/0x1230 kernel/rcu/tree.c:2122 rcu_gp_kthread+0x9c/0x340 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: CPU: 0 UID: 0 PID: 3225 Comm: kworker/R-bat_e Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026 Workqueue: bat_events batadv_dat_purge RIP: 0010:its_return_thunk+0x0/0x10 arch/x86/lib/retpoline.S:437 Code: cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 e9 fb b5 21 f5 cc RSP: 0018:ffffc90000006b70 EFLAGS: 00000292 RAX: 0b188840df950600 RBX: ffffffff8a30a692 RCX: 8000000000000101 RDX: 000000004dbb4af1 RSI: ffffffff8ea4b2ee RDI: ffffffff8c8fe680 RBP: 1ffff92000000d8c R08: ffffffff8178898f R09: 0000000000000000 R10: ffffc90000006c78 R11: ffffffff81b3bd40 R12: dffffc0000000000 R13: ffffffff8178898f R14: ffffc90000006c28 R15: 1ffff92000000d85 FS: 0000000000000000(0000) GS:ffff8881233d1000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000563248daf000 CR3: 000000000ff48000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000009 DR2: 0000000040000004 DR3: 0000000000000004 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: rcu_lock_acquire include/linux/rcupdate.h:309 [inline] rcu_read_lock include/linux/rcupdate.h:849 [inline] class_rcu_constructor include/linux/rcupdate.h:1216 [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 ref_tracker_alloc+0x267/0x530 lib/ref_tracker.c:276 __netdev_tracker_alloc include/linux/netdevice.h:4554 [inline] netdev_hold include/linux/netdevice.h:4583 [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:1690 [inline] __mkroute_output net/ipv4/route.c:2693 [inline] ip_route_output_key_hash_rcu+0x14ac/0x2720 net/ipv4/route.c:2913 ip_route_output_key_hash+0x18d/0x2a0 net/ipv4/route.c:2743 __ip_route_output_key include/net/route.h:175 [inline] ip_route_output_flow+0x2a/0x150 net/ipv4/route.c:2970 ip_route_output_key include/net/route.h:185 [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_ipv4+0x195/0x290 net/netfilter/nft_chain_filter.c:24 nf_hook_entry_hookfn include/linux/netfilter.h:165 [inline] nf_hook_slow+0xc5/0x220 net/netfilter/core.c:633 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:6405 [inline] __netif_receive_skb net/core/dev.c:6518 [inline] process_backlog+0xa6b/0x18b0 net/core/dev.c:6869 __napi_poll+0xaa/0x330 net/core/dev.c:7938 napi_poll net/core/dev.c:8001 [inline] net_rx_action+0x61d/0xf50 net/core/dev.c:8158 handle_softirqs+0x265/0x8d0 kernel/softirq.c:669 do_softirq+0x77/0xd0 kernel/softirq.c:569 __local_bh_enable_ip+0x100/0x140 kernel/softirq.c:473 spin_unlock_bh include/linux/spinlock.h:407 [inline] __batadv_dat_purge net/batman-adv/distributed-arp-table.c:252 [inline] batadv_dat_purge+0x2d7/0x3c0 net/batman-adv/distributed-arp-table.c:271 process_one_work kernel/workqueue.c:3495 [inline] process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3578 rescuer_thread+0x84a/0x12a0 kernel/workqueue.c:3803 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