rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5394/1:b..l rcu: (detected by 1, t=10503 jiffies, g=15061, q=1450262 ncpus=2) task:syz-executor state:R running task stack:23264 pid:5394 tgid:5394 ppid:5390 flags:0x00000002 Call Trace: context_switch kernel/sched/core.c:5328 [inline] __schedule+0xe55/0x5730 kernel/sched/core.c:6690 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7012 irqentry_exit+0x36/0x90 kernel/entry/common.c:354 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:stack_trace_consume_entry+0xe/0x170 kernel/stacktrace.c:83 Code: c4 ea ff ff ff eb c7 e8 40 06 a9 09 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 b8 00 00 00 00 00 fc ff df <55> 53 48 89 fb 48 83 c7 10 48 89 fa 48 83 ec 08 48 c1 ea 03 0f b6 RSP: 0018:ffffc9000441fa00 EFLAGS: 00000286 RAX: dffffc0000000000 RBX: ffffc9000441fa08 RCX: 0000000000000000 RDX: 1ffff92000883f4a RSI: ffffffff8b400130 RDI: ffffc9000441fac8 RBP: ffffc9000441fa98 R08: ffffc9000441fa3c R09: ffffffff91a31498 R10: ffffc9000441fa08 R11: 00000000000a2200 R12: ffffffff81794ad0 R13: ffffc9000441fac8 R14: 0000000000000000 R15: ffff88802d791e00 arch_stack_walk+0x86/0x100 arch/x86/kernel/stacktrace.c:27 stack_trace_save+0x95/0xd0 kernel/stacktrace.c:122 save_stack+0x162/0x1f0 mm/page_owner.c:156 __reset_page_owner+0x8d/0x400 mm/page_owner.c:297 reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1108 [inline] free_unref_page+0x5f4/0xdc0 mm/page_alloc.c:2638 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x4e/0x120 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x192/0x1e0 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:329 kasan_slab_alloc include/linux/kasan.h:247 [inline] slab_post_alloc_hook mm/slub.c:4085 [inline] slab_alloc_node mm/slub.c:4134 [inline] kmem_cache_alloc_noprof+0x121/0x2f0 mm/slub.c:4141 getname_flags.part.0+0x4c/0x550 fs/namei.c:139 getname_flags+0x93/0xf0 include/linux/audit.h:322 user_path_at+0x24/0x60 fs/namei.c:3015 ksys_umount fs/namespace.c:2033 [inline] __do_sys_umount fs/namespace.c:2041 [inline] __se_sys_umount fs/namespace.c:2039 [inline] __x64_sys_umount+0x10b/0x1a0 fs/namespace.c:2039 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f6b4c17f327 RSP: 002b:00007ffd4d27bfc8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f6b4c17f327 RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffd4d27c080 RBP: 00007ffd4d27c080 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffd4d27d100 R13: 00007f6b4c1f0134 R14: 00000000000223a4 R15: 00007ffd4d27d140 rcu: rcu_preempt kthread starved for 3034 jiffies! g15061 f0x2 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:27696 pid:17 tgid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5328 [inline] __schedule+0xe55/0x5730 kernel/sched/core.c:6690 __schedule_loop kernel/sched/core.c:6767 [inline] schedule+0xe7/0x350 kernel/sched/core.c:6782 schedule_timeout+0x136/0x2a0 kernel/time/timer.c:2615 rcu_gp_fqs_loop+0x1eb/0xb00 kernel/rcu/tree.c:2045 rcu_gp_kthread+0x271/0x380 kernel/rcu/tree.c:2247 kthread+0x2c1/0x3a0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 UID: 0 PID: 24 Comm: ksoftirqd/1 Not tainted 6.12.0-rc4-syzkaller-00047-gc2ee9f594da8 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 RIP: 0010:stack_access_ok+0xc/0x200 arch/x86/kernel/unwind_orc.c:389 Code: ff e9 b0 fe ff ff 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 48 b8 00 00 00 00 00 fc ff df 41 57 <41> 56 4c 8d 77 08 41 55 41 54 49 89 d4 4c 89 f2 55 48 c1 ea 03 48 RSP: 0018:ffffc900001e6f68 EFLAGS: 00000283 RAX: dffffc0000000000 RBX: 0000000000000001 RCX: ffffffff918017a8 RDX: 0000000000000008 RSI: ffffc900001e7ae0 RDI: ffffc900001e6fe8 RBP: ffffc900001e7ae0 R08: 0000000000000001 R09: ffffffff918017ac R10: ffffc900001e6fe8 R11: 000000000007fc54 R12: ffffc900001e7038 R13: ffffc900001e6fe8 R14: ffffc900001e7b10 R15: ffffc900001e7b08 FS: 0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fe2fe0c4690 CR3: 0000000032162000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: deref_stack_reg arch/x86/kernel/unwind_orc.c:403 [inline] unwind_next_frame+0x15dd/0x20c0 arch/x86/kernel/unwind_orc.c:648 arch_stack_walk+0x95/0x100 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x95/0xd0 kernel/stacktrace.c:122 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:579 poison_slab_object mm/kasan/common.c:247 [inline] __kasan_slab_free+0x51/0x70 mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:230 [inline] slab_free_hook mm/slub.c:2342 [inline] slab_free mm/slub.c:4579 [inline] kfree+0x14f/0x4b0 mm/slub.c:4727 skb_kfree_head net/core/skbuff.c:1086 [inline] skb_free_head+0x108/0x1d0 net/core/skbuff.c:1098 skb_release_data+0x560/0x730 net/core/skbuff.c:1125 skb_release_all net/core/skbuff.c:1190 [inline] __kfree_skb net/core/skbuff.c:1204 [inline] consume_skb net/core/skbuff.c:1436 [inline] consume_skb+0xbf/0x100 net/core/skbuff.c:1430 nft_synproxy_eval_v4 net/netfilter/nft_synproxy.c:60 [inline] nft_synproxy_do_eval+0xa51/0xd60 net/netfilter/nft_synproxy.c:141 expr_call_ops_eval net/netfilter/nf_tables_core.c:240 [inline] nft_do_chain+0x2e6/0x18f0 net/netfilter/nf_tables_core.c:288 nft_do_chain_inet+0x18b/0x350 net/netfilter/nft_chain_filter.c:161 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline] nf_hook_slow+0xbb/0x200 net/netfilter/core.c:626 nf_hook.constprop.0+0x42e/0x750 include/linux/netfilter.h:269 NF_HOOK include/linux/netfilter.h:312 [inline] ip_local_deliver+0x169/0x1f0 net/ipv4/ip_input.c:254 dst_input include/net/dst.h:460 [inline] ip_rcv_finish net/ipv4/ip_input.c:449 [inline] NF_HOOK include/linux/netfilter.h:314 [inline] NF_HOOK include/linux/netfilter.h:308 [inline] ip_rcv+0x2c3/0x5d0 net/ipv4/ip_input.c:569 __netif_receive_skb_one_core+0x199/0x1e0 net/core/dev.c:5666 __netif_receive_skb+0x1d/0x160 net/core/dev.c:5779 process_backlog+0x443/0x15f0 net/core/dev.c:6111 __napi_poll.constprop.0+0xb7/0x550 net/core/dev.c:6775 napi_poll net/core/dev.c:6844 [inline] net_rx_action+0xa92/0x1010 net/core/dev.c:6966 handle_softirqs+0x213/0x8f0 kernel/softirq.c:554 run_ksoftirqd kernel/softirq.c:927 [inline] run_ksoftirqd+0x3a/0x60 kernel/softirq.c:919 smpboot_thread_fn+0x661/0xa30 kernel/smpboot.c:164 kthread+0x2c1/0x3a0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244