rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5919/1:b..l rcu: (detected by 0, t=10502 jiffies, g=46525, q=74 ncpus=2) task:syz-executor state:R running task stack:21160 pid:5919 ppid:5911 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x1553/0x45a0 kernel/sched/core.c:6700 preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6867 preempt_schedule+0xc0/0xd0 kernel/sched/core.c:6891 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45 unwind_next_frame+0x200f/0x2970 arch/x86/kernel/unwind_orc.c:672 arch_stack_walk+0x144/0x190 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xaa/0x100 kernel/stacktrace.c:122 save_stack+0x125/0x230 mm/page_owner.c:128 __reset_page_owner+0x4e/0x190 mm/page_owner.c:149 reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1181 [inline] free_unref_page_prepare+0x7b2/0x8c0 mm/page_alloc.c:2365 free_unref_page_list+0xbe/0x860 mm/page_alloc.c:2504 release_pages+0x1f7a/0x2200 mm/swap.c:1022 __folio_batch_release+0x71/0xe0 mm/swap.c:1042 folio_batch_release include/linux/pagevec.h:83 [inline] shmem_undo_range+0x630/0x1b20 mm/shmem.c:1026 shmem_truncate_range mm/shmem.c:1135 [inline] shmem_evict_inode+0x245/0x9e0 mm/shmem.c:1264 evict+0x4ca/0x8d0 fs/inode.c:705 do_unlinkat+0x38c/0x590 fs/namei.c:4406 __do_sys_unlink fs/namei.c:4447 [inline] __se_sys_unlink fs/namei.c:4445 [inline] __x64_sys_unlink+0x49/0x50 fs/namei.c:4445 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f9e5739bf47 RSP: 002b:00007ffe831acf28 EFLAGS: 00000206 ORIG_RAX: 0000000000000057 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f9e5739bf47 RDX: 00007ffe831acf50 RSI: 00007ffe831acfe0 RDI: 00007ffe831acfe0 RBP: 00007ffe831acfe0 R08: 00007ffe831adfe0 R09: 00000000ffffffff R10: 0000000000000100 R11: 0000000000000206 R12: 00007ffe831ae070 R13: 00007f9e574321ca R14: 0000000000084065 R15: 00007ffe831ae0b0 rcu: rcu_preempt kthread starved for 10543 jiffies! g46525 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:27720 pid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x1553/0x45a0 kernel/sched/core.c:6700 schedule+0xbd/0x170 kernel/sched/core.c:6774 schedule_timeout+0x188/0x2d0 kernel/time/timer.c:2168 rcu_gp_fqs_loop+0x313/0x1590 kernel/rcu/tree.c:1667 rcu_gp_kthread+0x9d/0x3b0 kernel/rcu/tree.c:1866 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 12096 Comm: syz.1.1623 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:unwind_next_frame+0x12b/0x2970 arch/x86/kernel/unwind_orc.c:482 Code: 00 41 0f b7 1e 89 de 83 e6 03 31 ff e8 ee f1 4b 00 83 e3 03 74 1b e8 c4 ee 4b 00 e9 f7 20 00 00 e8 ba ee 4b 00 e9 26 21 00 00 b0 ee 4b 00 eb 05 e8 a9 ee 4b 00 4c 89 7c 24 78 4d 8d 74 24 35 RSP: 0018:ffffc900001efb38 EFLAGS: 00000246 RAX: 1ffff9200003df8b RBX: 1ffff9200003df81 RCX: ffffffff972ce403 RDX: ffff8880454e8000 RSI: 0000000000000001 RDI: 0000000000000001 RBP: ffffc900001efc58 R08: ffffc900001efcd0 R09: 0000000000000017 R10: 0000000000000004 R11: 0000000000000100 R12: ffffc900001efc08 R13: dffffc0000000000 R14: 0000000000000000 R15: ffffffff8aa0144a FS: 00007f44e545e6c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c30185c CR3: 000000002cf2e000 CR4: 00000000003506e0 Call Trace: arch_stack_walk+0x144/0x190 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xaa/0x100 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4e/0x70 mm/kasan/common.c:53 kasan_save_free_info+0x2e/0x50 mm/kasan/generic.c:522 ____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:237 kasan_slab_free include/linux/kasan.h:164 [inline] slab_free_hook mm/slub.c:1811 [inline] slab_free_freelist_hook+0x130/0x1a0 mm/slub.c:1837 slab_free mm/slub.c:3830 [inline] __kmem_cache_free+0xba/0x1e0 mm/slub.c:3843 skb_kfree_head net/core/skbuff.c:946 [inline] skb_free_head net/core/skbuff.c:958 [inline] skb_release_data+0x5dc/0x7b0 net/core/skbuff.c:988 skb_release_all net/core/skbuff.c:1054 [inline] kfree_skb_add_bulk net/core/skbuff.c:1125 [inline] kfree_skb_list_reason+0x264/0x460 net/core/skbuff.c:1147 __dev_xmit_skb net/core/dev.c:3950 [inline] __dev_queue_xmit+0x1fbe/0x3660 net/core/dev.c:4416 dev_queue_xmit include/linux/netdevice.h:3113 [inline] neigh_hh_output include/net/neighbour.h:527 [inline] neigh_output include/net/neighbour.h:541 [inline] ip_finish_output2+0xcec/0x11e0 net/ipv4/ip_output.c:235 NF_HOOK_COND include/linux/netfilter.h:293 [inline] ip_output+0x2a1/0x3b0 net/ipv4/ip_output.c:436 iptunnel_xmit+0x4f0/0x920 net/ipv4/ip_tunnel_core.c:82 udp_tunnel_xmit_skb+0x249/0x390 net/ipv4/udp_tunnel_core.c:172 tipc_udp_xmit+0x861/0xb40 net/tipc/udp_media.c:198 tipc_udp_send_msg+0x27e/0x3e0 net/tipc/udp_media.c:271 tipc_bearer_xmit_skb+0x2ad/0x3f0 net/tipc/bearer.c:575 tipc_disc_timeout+0x596/0x6f0 net/tipc/discover.c:338 call_timer_fn+0x189/0x540 kernel/time/timer.c:1701 expire_timers kernel/time/timer.c:1752 [inline] __run_timers+0x542/0x800 kernel/time/timer.c:2023 run_timer_softirq+0x67/0xf0 kernel/time/timer.c:2036 handle_softirqs+0x280/0x820 kernel/softirq.c:578 __do_softirq kernel/softirq.c:612 [inline] invoke_softirq kernel/softirq.c:452 [inline] __irq_exit_rcu+0xd3/0x190 kernel/softirq.c:661 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline] sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline] RIP: 0010:_raw_spin_unlock_irq+0x29/0x50 kernel/locking/spinlock.c:202 Code: 00 f3 0f 1e fa 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 8a 1d d8 f6 48 89 df e8 42 f2 d8 f6 e8 cd 04 fd f6 fb bf 01 00 00 00 22 f9 cb f6 65 8b 05 73 20 73 75 85 c0 74 02 5b c3 e8 f0 07 70 RSP: 0018:ffffc9000c58fc78 EFLAGS: 00000286 RAX: 46e415a8aa81ed00 RBX: ffff88805aca5c80 RCX: 46e415a8aa81ed00 RDX: dffffc0000000000 RSI: ffffffff8acacbe0 RDI: 0000000000000001 RBP: ffff88805aca6118 R08: ffffffff8e8b2fef R09: 1ffffffff1d165fd R10: dffffc0000000000 R11: fffffbfff1d165fe R12: 1ffff1100b594c23 R13: 0000000000000021 R14: dffffc0000000000 R15: 0000000000000000 spin_unlock_irq include/linux/spinlock.h:401 [inline] get_signal+0x11f5/0x13f0 kernel/signal.c:2905 arch_do_signal_or_restart+0xc2/0x800 arch/x86/kernel/signal.c:310 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline] syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302 do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f44e459ce57 Code: 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 <0f> 05 48 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 RSP: 002b:00007f44e545e0e8 EFLAGS: 00000246 RAX: 00000000000000ca RBX: 00007f44e4816188 RCX: 00007f44e459ce59 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f44e4816188 RBP: 00007f44e4816180 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f44e4816218 R14: 00007ffeef346e70 R15: 00007ffeef346f58 GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog