rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5825/1:b..l rcu: (detected by 1, t=10503 jiffies, g=57021, q=355 ncpus=2) task:syz-executor state:R running task stack:24232 pid:5825 tgid:5825 ppid:1 task_flags:0x40054c flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x116f/0x5de0 kernel/sched/core.c:6767 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7090 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:on_stack arch/x86/include/asm/stacktrace.h:60 [inline] RIP: 0010:stack_access_ok+0x9c/0x200 arch/x86/kernel/unwind_orc.c:393 Code: 84 c0 74 08 3c 03 0f 8e 0b 01 00 00 8b 13 85 d2 74 23 49 39 ef 77 1e 48 39 e9 76 19 4a 8d 54 25 00 49 39 d7 0f 92 c0 48 39 d1 <0f> 93 c2 20 d0 0f 85 ba 00 00 00 48 8d 7b 28 48 8d 4b 20 48 b8 00 RSP: 0018:ffffc90003f8f4f8 EFLAGS: 00000202 RAX: 0000000000000001 RBX: ffffc90003f8f5a8 RCX: ffffc90003f90000 RDX: ffffc90003f8fbc0 RSI: ffffc90003f8fbb8 RDI: ffffc90003f8f5a8 RBP: ffffc90003f8fbb8 R08: ffffffff911aeb30 R09: 0000000000000000 R10: 0000000000000001 R11: 00000000000079fe R12: 0000000000000008 R13: ffffc90003f8f5b8 R14: ffffc90003f8f5b0 R15: ffffc90003f88000 deref_stack_reg arch/x86/kernel/unwind_orc.c:403 [inline] unwind_next_frame+0xb7d/0x20a0 arch/x86/kernel/unwind_orc.c:585 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_record_aux_stack+0xb8/0xd0 mm/kasan/generic.c:548 __call_rcu_common.constprop.0+0x9a/0x9f0 kernel/rcu/tree.c:3082 slab_free_hook mm/slub.c:2353 [inline] slab_free mm/slub.c:4646 [inline] kmem_cache_free+0x173/0x4d0 mm/slub.c:4748 exit_mmap+0x511/0xb90 mm/mmap.c:1309 __mmput+0x12a/0x410 kernel/fork.c:1379 mmput+0x62/0x70 kernel/fork.c:1401 exit_mm kernel/exit.c:586 [inline] do_exit+0x9d1/0x2d10 kernel/exit.c:941 do_group_exit+0xd3/0x2a0 kernel/exit.c:1103 get_signal+0x2673/0x26d0 kernel/signal.c:3036 arch_do_signal_or_restart+0x8f/0x7d0 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+0x150/0x2a0 kernel/entry/common.c:218 do_syscall_64+0xda/0x260 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fbef0d8ca61 RSP: 002b:00007fff21d10e70 EFLAGS: 00000287 ORIG_RAX: 0000000000000101 RAX: 0000000000000003 RBX: 00000000000005c8 RCX: 00007fbef0d8ca61 RDX: 0000000000090800 RSI: 00007fbef0e0e5c0 RDI: 00000000ffffff9c RBP: 00007fff21d10f1c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000287 R12: 00000000000001aa R13: 0000000000000000 R14: 00000000000c5f3f R15: 00007fff21d10f70 rcu: rcu_preempt kthread starved for 9820 jiffies! g57021 f0x0 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:27688 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x116f/0x5de0 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6860 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2046 rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2248 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153 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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.14.0-syzkaller-12508-g92b71befc349 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:separate_irq_context kernel/locking/lockdep.c:4704 [inline] RIP: 0010:__lock_acquire+0x4f5/0x1ba0 kernel/locking/lockdep.c:5219 Code: 0a 48 83 f9 ff 0f 85 56 05 00 00 c7 44 24 2c 01 00 00 00 48 89 0b 41 8b 86 e8 0a 00 00 85 c0 74 14 48 8d 04 80 0f b6 44 c5 f9 <32> 43 21 a8 60 0f 85 6e 05 00 00 48 89 c8 89 4c 24 10 48 c1 e8 20 RSP: 0018:ffffc90000006ff0 EFLAGS: 00000002 RAX: 0000000000000020 RBX: ffffffff8e098280 RCX: f501fefe41178ce3 RDX: 0000000000000000 RSI: ffffffff8e098280 RDI: ffffffff8e097740 RBP: ffffffff8e098230 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: ffffffff8e3c15c0 R12: 0000000000000003 R13: 0000000000000001 R14: ffffffff8e097740 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881249bb000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f0042377d38 CR3: 0000000034d1a000 CR4: 00000000003526f0 DR0: 0000000000000001 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: lock_acquire kernel/locking/lockdep.c:5866 [inline] lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5823 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:841 [inline] class_rcu_constructor include/linux/rcupdate.h:1155 [inline] unwind_next_frame+0xd1/0x20a0 arch/x86/kernel/unwind_orc.c:479 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 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:576 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:233 [inline] slab_free_hook mm/slub.c:2389 [inline] slab_free mm/slub.c:4646 [inline] kmem_cache_free+0x2d4/0x4d0 mm/slub.c:4748 kfree_skbmem+0x1a4/0x1f0 net/core/skbuff.c:1120 __kfree_skb net/core/skbuff.c:1177 [inline] consume_skb net/core/skbuff.c:1408 [inline] consume_skb+0xcc/0x100 net/core/skbuff.c:1402 nft_synproxy_eval_v4 net/netfilter/nft_synproxy.c:60 [inline] nft_synproxy_do_eval+0xa6b/0xd80 net/netfilter/nft_synproxy.c:141 expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline] nft_do_chain+0x2e6/0x1920 net/netfilter/nf_tables_core.c:285 nft_do_chain_inet+0x18a/0x340 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+0x422/0x750 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:469 [inline] ip_rcv_finish net/ipv4/ip_input.c:447 [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:567 __netif_receive_skb_one_core+0x197/0x1e0 net/core/dev.c:5891 __netif_receive_skb+0x1d/0x160 net/core/dev.c:6004 process_backlog+0x442/0x15e0 net/core/dev.c:6356 __napi_poll.constprop.0+0xb7/0x550 net/core/dev.c:7328 napi_poll net/core/dev.c:7392 [inline] net_rx_action+0xa97/0x1010 net/core/dev.c:7514 handle_softirqs+0x216/0x8e0 kernel/softirq.c:579 __do_softirq kernel/softirq.c:613 [inline] invoke_softirq kernel/softirq.c:453 [inline] __irq_exit_rcu+0x109/0x170 kernel/softirq.c:680 irq_exit_rcu+0x9/0x30 kernel/softirq.c:696 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1049 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:native_irq_disable arch/x86/include/asm/irqflags.h:37 [inline] RIP: 0010:arch_local_irq_disable arch/x86/include/asm/irqflags.h:92 [inline] RIP: 0010:acpi_safe_halt+0x1a/0x20 drivers/acpi/processor_idle.c:112 Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 65 48 8b 05 50 bf 34 08 48 8b 00 a8 08 75 0c 66 90 0f 00 2d 28 2f 8e 00 fb f4 c3 cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffffff8e007d68 EFLAGS: 00000246 RAX: 0000000000004000 RBX: 0000000000000001 RCX: ffffffff8b7173e9 RDX: 0000000000000001 RSI: ffff888141692800 RDI: ffff888141692864 RBP: ffff888141692864 R08: 0000000000000001 R09: ffffed10170865bd R10: ffff8880b8432deb R11: 0000000000000000 R12: ffff888020721800 R13: ffffffff8f0496a0 R14: 0000000000000000 R15: 0000000000000000 acpi_idle_enter+0xc5/0x160 drivers/acpi/processor_idle.c:701 cpuidle_enter_state+0xb2/0x510 drivers/cpuidle/cpuidle.c:268 cpuidle_enter+0x4e/0xa0 drivers/cpuidle/cpuidle.c:389 call_cpuidle kernel/sched/idle.c:155 [inline] cpuidle_idle_call kernel/sched/idle.c:230 [inline] do_idle+0x378/0x510 kernel/sched/idle.c:325 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:423 rest_init+0x16b/0x2b0 init/main.c:743 start_kernel+0x3e9/0x4d0 init/main.c:1099 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:513 x86_64_start_kernel+0xb0/0xc0 arch/x86/kernel/head64.c:494 common_startup_64+0x13e/0x148