rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P9027/1:b..l P29/1:b..l P9034/1:b..l rcu: (detected by 0, t=10502 jiffies, g=47133, q=499 ncpus=2) task:sed state:R running task stack:25632 pid:9034 tgid:9034 ppid:9033 task_flags:0x400000 flags:0x00080800 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1821/0x5740 kernel/sched/core.c:7189 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7513 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x14f/0x760 kernel/entry/common.c:164 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:__orc_find arch/x86/kernel/unwind_orc.c:100 [inline] RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:238 [inline] RIP: 0010:unwind_next_frame+0x534/0x2550 arch/x86/kernel/unwind_orc.c:510 Code: 0f b6 04 08 84 c0 75 27 49 63 07 4c 01 f8 49 8d 4f 04 4c 39 e0 48 0f 46 e9 49 8d 47 fc 48 0f 47 d8 4d 0f 46 ef 48 39 dd 76 a2 7b fd ff ff 44 89 f9 80 e1 07 80 c1 03 38 c1 7c cc 4c 89 ff 48 RSP: 0018:ffffc90005886c98 EFLAGS: 00000212 RAX: ffffffff9052b938 RBX: ffffffff9052b93c RCX: ffffffff9052b940 RDX: ffffffff9052b93c RSI: ffffffff90d33678 RDI: ffffffff8c28b780 RBP: ffffffff9052b940 R08: 000000000000000a R09: ffffffff8e95cca0 R10: ffffc90005886db8 R11: ffffffff81b0e040 R12: ffffffff82310858 R13: ffffffff9052b93c R14: ffffc90005886d68 R15: ffffffff9052b93c 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:165 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:320 reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1402 [inline] __free_frozen_pages+0xbc7/0xd30 mm/page_alloc.c:2943 __slab_free+0x274/0x2c0 mm/slub.c:5613 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_slab_alloc+0x22/0x80 mm/kasan/common.c:350 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4570 [inline] slab_alloc_node mm/slub.c:4899 [inline] kmem_cache_alloc_noprof+0x2bc/0x650 mm/slub.c:4906 ptlock_alloc+0x20/0x70 mm/memory.c:7579 ptlock_init include/linux/mm.h:3741 [inline] pagetable_pte_ctor include/linux/mm.h:3790 [inline] __pte_alloc_one_noprof include/asm-generic/pgalloc.h:79 [inline] pte_alloc_one+0x7a/0x370 arch/x86/mm/pgtable.c:18 __pte_alloc+0x25/0x1a0 mm/memory.c:453 move_page_tables+0x186a/0x1c10 mm/mremap.c:870 relocate_vma_down+0x3ab/0x590 mm/vma_exec.c:67 setup_arg_pages+0x70a/0xbd0 fs/exec.c:690 load_elf_binary+0xc5e/0x2980 fs/binfmt_elf.c:1028 search_binary_handler fs/exec.c:1664 [inline] exec_binprm fs/exec.c:1696 [inline] bprm_execve+0x94a/0x1510 fs/exec.c:1748 do_execveat_common+0x50d/0x690 fs/exec.c:1846 __do_sys_execve fs/exec.c:1930 [inline] __se_sys_execve fs/exec.c:1924 [inline] __x64_sys_execve+0x97/0xc0 fs/exec.c:1924 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff564001107 RSP: 002b:00007fff57468a58 EFLAGS: 00000246 ORIG_RAX: 000000000000003b RAX: ffffffffffffffda RBX: 0000559710d1d188 RCX: 00007ff564001107 RDX: 0000559710d1d1b0 RSI: 0000559710d1d188 RDI: 0000559710d1d268 RBP: 0000559710d1d268 R08: 00007fff5746ee10 R09: 0000000000000000 R10: 0000000000000008 R11: 0000000000000246 R12: 0000559710d1d1b0 R13: 00007ff5641c6e8b R14: 0000559710d1d1b0 R15: 0000000000000000 task:kworker/1:1 state:R running task stack:20768 pid:29 tgid:29 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: mld mld_ifc_work Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1821/0x5740 kernel/sched/core.c:7189 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7513 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x14f/0x760 kernel/entry/common.c:164 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:deref_stack_reg+0x13/0x230 arch/x86/kernel/unwind_orc.c:418 Code: fe ff ff 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 41 57 41 56 41 55 41 54 53 48 83 ec 20 48 89 54 24 18 <49> 89 f0 49 89 ff 48 be 00 00 00 00 00 fc ff df 48 8d 5f 08 49 89 RSP: 0018:ffffc90000a571c0 EFLAGS: 00000286 RAX: fffffffffffffff0 RBX: ffffffff90c9d476 RCX: 0000000000000000 RDX: ffffc90000a57328 RSI: ffffc90000a57410 RDI: ffffc90000a572e8 RBP: dffffc0000000000 R08: ffffc90000a57347 R09: 0000000000000000 R10: ffffc90000a57338 R11: fffff5200014ae69 R12: ffffc90000a57410 R13: 1ffff9200014ae5f R14: ffffc90000a572e8 R15: 1ffffffff2193a8f unwind_next_frame+0x19d5/0x2550 arch/x86/kernel/unwind_orc.c:-1 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:165 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:320 reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1402 [inline] __free_frozen_pages+0xbc7/0xd30 mm/page_alloc.c:2943 __slab_free+0x274/0x2c0 mm/slub.c:5613 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:5296 [inline] __kmalloc_node_track_caller_noprof+0x4db/0x7b0 mm/slub.c:5408 kmalloc_reserve net/core/skbuff.c:635 [inline] __alloc_skb+0x2c1/0x7d0 net/core/skbuff.c:713 alloc_skb include/linux/skbuff.h:1383 [inline] mld_newpack+0x14c/0xc90 net/ipv6/mcast.c:1775 add_grhead+0x5a/0x2a0 net/ipv6/mcast.c:1886 add_grec+0x1452/0x1740 net/ipv6/mcast.c:2025 mld_send_cr net/ipv6/mcast.c:2148 [inline] mld_ifc_work+0x6e6/0xe70 net/ipv6/mcast.c:2693 process_one_work kernel/workqueue.c:3314 [inline] process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3397 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3478 kthread+0x389/0x470 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 task:syz.0.1030 state:R running task stack:25280 pid:9027 tgid:9023 ppid:5646 task_flags:0x400040 flags:0x08080002 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1821/0x5740 kernel/sched/core.c:7189 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7513 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x14f/0x760 kernel/entry/common.c:164 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_is_held_type+0x9/0x150 kernel/locking/lockdep.c:5925 Code: d1 19 8e 67 48 0f b9 3a 90 eb ce 66 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 55 41 57 41 56 <41> 55 41 54 53 bb ff ff ff ff 83 3d 56 a6 87 04 00 0f 84 e4 00 00 RSP: 0018:ffffc90002f4f420 EFLAGS: 00000246 RAX: ffffffff8ba2f6ff RBX: dffffc0000000000 RCX: 0000000000080000 RDX: ffffc9000e7fd000 RSI: 00000000ffffffff RDI: ffff88802924d8f8 RBP: ffff88802924d8f8 R08: ffff88802fce1ec0 R09: 0000000000000005 R10: 0000000000000004 R11: 0000000000000002 R12: ffff88804dfab8c0 R13: 0000000080ffffff R14: 0000000000000300 R15: 000000000000000a lock_is_held include/linux/lockdep.h:249 [inline] mt_locked lib/maple_tree.c:-1 [inline] mt_slot lib/maple_tree.c:715 [inline] mtree_range_walk+0x55e/0x8b0 lib/maple_tree.c:2050 mas_state_walk lib/maple_tree.c:2952 [inline] mt_find+0x25f/0x630 lib/maple_tree.c:6271 find_vma+0xed/0x160 mm/mmap.c:908 lock_mm_and_find_vma+0x66/0x340 mm/mmap_lock.c:504 do_user_addr_fault+0x330/0x1340 arch/x86/mm/fault.c:1357 handle_page_fault arch/x86/mm/fault.c:1474 [inline] exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1527 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 RIP: 0010:rep_movs_alternative+0x30/0x90 arch/x86/lib/copy_user_64.S:60 Code: 83 f9 08 73 25 85 c9 74 0f 8a 06 88 07 48 ff c7 48 ff c6 48 ff c9 75 f1 c3 cc cc cc cc 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 <48> 8b 06 48 89 07 48 83 c6 08 48 83 c7 08 83 e9 08 74 db 83 f9 08 RSP: 0018:ffffc90002f4f8b8 EFLAGS: 00050206 RAX: 00007ffffffff001 RBX: 000000000000001c RCX: 000000000000001c RDX: 0000000000000001 RSI: 00000000800af000 RDI: ffffc90002f4f940 RBP: ffffc90002f4f9d0 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff520005e9f2b R12: dffffc0000000000 R13: ffffc90002f4fc80 R14: ffffc90002f4f940 R15: 00000000800af000 copy_user_generic arch/x86/include/asm/uaccess_64.h:126 [inline] raw_copy_from_user arch/x86/include/asm/uaccess_64.h:141 [inline] _inline_copy_from_user include/linux/uaccess.h:185 [inline] _copy_from_user+0x7a/0xb0 lib/usercopy.c:18 copy_from_user include/linux/uaccess.h:223 [inline] get_compat_msghdr+0xb3/0x4c0 net/compat.c:91 recvmsg_copy_msghdr net/socket.c:2882 [inline] ___sys_recvmsg+0x1dd/0x590 net/socket.c:2956 do_recvmmsg+0x3a5/0x800 net/socket.c:3047 __sys_recvmmsg+0x1a5/0x290 net/socket.c:3129 __do_compat_sys_recvmmsg_time32 net/compat.c:418 [inline] __se_compat_sys_recvmmsg_time32 net/compat.c:414 [inline] __ia32_compat_sys_recvmmsg_time32+0xbf/0xe0 net/compat.c:414 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0x229/0x6e0 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x33/0x70 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf70cf01c RSP: 002b:00000000f549c50c EFLAGS: 00000206 ORIG_RAX: 0000000000000151 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000800000c0 RDX: 0000000000010106 RSI: 0000000000000002 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 7202 jiffies! g47133 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:27968 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1821/0x5740 kernel/sched/core.c:7189 __schedule_loop kernel/sched/core.c:7268 [inline] schedule+0x164/0x360 kernel/sched/core.c:7283 schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x312/0x11d0 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2297 kthread+0x389/0x470 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: 0 Comm: swapper/1 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:231 [inline] RIP: 0010:unwind_next_frame+0x24a/0x2550 arch/x86/kernel/unwind_orc.c:510 Code: 8b 6d 00 44 89 f8 ff c0 48 8d 2c 85 f8 6b 71 91 48 89 e8 48 c1 e8 03 0f b6 04 18 84 c0 0f 85 85 1d 00 00 44 8b 45 00 41 ff c0 <4a> 8d 04 6d 00 00 00 00 4c 01 e8 48 8d 34 45 3c 32 bc 90 48 81 fe RSP: 0018:ffffc90000a07698 EFLAGS: 00000206 RAX: 0000000000000000 RBX: dffffc0000000000 RCX: 0000000080000300 RDX: 00000000000aad3e RSI: ffffffff8c28b7c0 RDI: ffffffff8c28b780 RBP: ffffffff919371bc R08: 000000000017fc21 R09: ffffffff8e95cca0 R10: ffffc90000a077b8 R11: ffffffff81b0e040 R12: ffffffff89817046 R13: 000000000017fc20 R14: ffffc90000a07768 R15: 0000000000088170 FS: 0000000000000000(0000) GS:ffff888125387000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000800aa018 CR3: 000000006d5a4000 CR4: 00000000003526f0 Call Trace: 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 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4570 [inline] slab_alloc_node mm/slub.c:4899 [inline] kmem_cache_alloc_noprof+0x2bc/0x650 mm/slub.c:4906 skb_clone+0x212/0x3a0 net/core/skbuff.c:2107 dev_queue_xmit_nit+0x29a/0xad0 net/core/dev.c:2574 xmit_one net/core/dev.c:3884 [inline] dev_hard_start_xmit+0x1c1/0x830 net/core/dev.c:3904 sch_direct_xmit+0x251/0x4c0 net/sched/sch_generic.c:372 qdisc_restart net/sched/sch_generic.c:437 [inline] __qdisc_run+0xa83/0x1560 net/sched/sch_generic.c:445 qdisc_run include/net/pkt_sched.h:120 [inline] __dev_xmit_skb net/core/dev.c:4292 [inline] __dev_queue_xmit+0x1d26/0x3950 net/core/dev.c:4831 dev_queue_xmit include/linux/netdevice.h:3418 [inline] neigh_hh_output include/net/neighbour.h:544 [inline] neigh_output include/net/neighbour.h:558 [inline] ip_finish_output2+0xc68/0x1070 net/ipv4/ip_output.c:237 NF_HOOK_COND include/linux/netfilter.h:307 [inline] ip_output+0x29f/0x450 net/ipv4/ip_output.c:438 synproxy_send_client_synack+0x8c1/0xe30 net/netfilter/nf_synproxy_core.c:485 nft_synproxy_eval_v4+0x34a/0x4e0 net/netfilter/nft_synproxy.c:60 nft_synproxy_do_eval+0x305/0x580 net/netfilter/nft_synproxy.c:142 expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline] nft_do_chain+0x48d/0x1ae0 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:158 [inline] nf_hook_slow+0xc5/0x220 net/netfilter/core.c:619 nf_hook include/linux/netfilter.h:273 [inline] NF_HOOK+0x21f/0x3c0 include/linux/netfilter.h:316 NF_HOOK+0x336/0x3c0 include/linux/netfilter.h:318 __netif_receive_skb_one_core net/core/dev.c:6202 [inline] __netif_receive_skb net/core/dev.c:6315 [inline] process_backlog+0xaa3/0x1950 net/core/dev.c:6666 __napi_poll+0xae/0x340 net/core/dev.c:7733 napi_poll net/core/dev.c:7796 [inline] net_rx_action+0x627/0xf70 net/core/dev.c:7953 handle_softirqs+0x22a/0x840 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0xca/0x220 kernel/softirq.c:735 irq_exit_rcu+0x9/0x30 kernel/softirq.c:752 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1061 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:63 Code: 6b 7d 02 e9 93 f7 02 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d f3 01 20 00 fb f4 cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 RSP: 0018:ffffc90000197e20 EFLAGS: 00000242 RAX: 0000000000e60079 RBX: ffffffff819a858a RCX: 0000000080000001 RDX: 0000000000000001 RSI: ffffffff8dfad387 RDI: ffffffff8c28b7e0 RBP: ffffc90000197f10 R08: ffff8880b87339db R09: 1ffff110170e673b R10: dffffc0000000000 R11: ffffed10170e673c R12: 0000000000000001 R13: 1ffff11003b5b000 R14: 0000000000000001 R15: 1ffff11003b5b000 arch_safe_halt arch/x86/kernel/process.c:766 [inline] default_idle+0x9/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x72/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:199 [inline] do_idle+0x36a/0x5f0 kernel/sched/idle.c:352 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:451 start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:312 common_startup_64+0x13e/0x147