rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: (detected by 0, t=10502 jiffies, g=62569, q=2882213 ncpus=2) rcu: All QSes seen, last rcu_preempt kthread activity 2249 (4294994384-4294992135), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 2250 jiffies! g62569 f0x2 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:25136 pid:17 tgid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5328 [inline] __schedule+0x18af/0x4bd0 kernel/sched/core.c:6690 __schedule_loop kernel/sched/core.c:6767 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6782 schedule_timeout+0x1be/0x310 kernel/time/timer.c:2615 rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:2045 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2247 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/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: 0 UID: 0 PID: 16 Comm: ksoftirqd/0 Not tainted 6.12.0-rc5-syzkaller-00308-g3e5e6c9900c3 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 RIP: 0010:preempt_count_sub+0x6/0x170 kernel/sched/core.c:5818 Code: c7 c7 00 3c 1d 90 e8 39 69 9b 00 e9 66 ff ff ff 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 41 56 <53> 89 fb 48 c7 c0 40 49 3d 9a 48 c1 e8 03 49 be 00 00 00 00 00 fc RSP: 0018:ffffc90000006580 EFLAGS: 00000246 RAX: 0000000000000001 RBX: ffffffff909e1430 RCX: ffffffff902a53ac RDX: ffffffff909e142c RSI: ffffffff909e13b4 RDI: 0000000000000001 RBP: ffffc900000066b0 R08: 000000000000001b R09: ffffc90000006750 R10: ffffc900000066b0 R11: ffffffff81809280 R12: dffffc0000000000 R13: ffffc90000006660 R14: ffffffff909e1431 R15: ffffffff81005689 FS: 0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f0a7fa00210 CR3: 000000000e734000 CR4: 00000000003526f0 DR0: 00000000ffffa0dd DR1: 0000000000000000 DR2: 0000000000000000 DR3: 00000000d29dafa1 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: unwind_next_frame+0x193b/0x22d0 arch/x86/kernel/unwind_orc.c:679 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x118/0x1d0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:377 [inline] __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:394 kasan_kmalloc include/linux/kasan.h:257 [inline] __kmalloc_cache_noprof+0x19c/0x2c0 mm/slub.c:4295 kmalloc_noprof include/linux/slab.h:878 [inline] slab_free_hook mm/slub.c:2294 [inline] slab_free mm/slub.c:4579 [inline] kmem_cache_free+0x177/0x420 mm/slub.c:4681 nf_conntrack_free+0x2fd/0x390 net/netfilter/nf_conntrack_core.c:1735 nf_ct_put include/net/netfilter/nf_conntrack.h:186 [inline] nf_conntrack_in+0xb51/0x1890 net/netfilter/nf_conntrack_core.c:2061 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline] nf_hook_slow+0xc3/0x220 net/netfilter/core.c:626 nf_hook+0x2c4/0x450 include/linux/netfilter.h:269 __ip_local_out+0x3d9/0x4e0 net/ipv4/ip_output.c:119 ip_local_out+0x26/0x70 net/ipv4/ip_output.c:128 synproxy_send_client_synack+0x8b8/0xf30 net/netfilter/nf_synproxy_core.c:484 nft_synproxy_eval_v4+0x3ca/0x610 net/netfilter/nft_synproxy.c:59 nft_synproxy_do_eval+0x362/0xa60 net/netfilter/nft_synproxy.c:141 expr_call_ops_eval net/netfilter/nf_tables_core.c:240 [inline] nft_do_chain+0x4ad/0x1da0 net/netfilter/nf_tables_core.c:288 nft_do_chain_inet+0x418/0x6b0 net/netfilter/nft_chain_filter.c:161 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline] nf_hook_slow+0xc3/0x220 net/netfilter/core.c:626 nf_hook include/linux/netfilter.h:269 [inline] NF_HOOK+0x29e/0x450 include/linux/netfilter.h:312 NF_HOOK+0x3a4/0x450 include/linux/netfilter.h:314 __netif_receive_skb_one_core net/core/dev.c:5670 [inline] __netif_receive_skb+0x2bf/0x650 net/core/dev.c:5783 process_backlog+0x662/0x15b0 net/core/dev.c:6115 __napi_poll+0xcb/0x490 net/core/dev.c:6779 napi_poll net/core/dev.c:6848 [inline] net_rx_action+0x89b/0x1240 net/core/dev.c:6970 handle_softirqs+0x2c5/0x980 kernel/softirq.c:554 __do_softirq kernel/softirq.c:588 [inline] invoke_softirq kernel/softirq.c:428 [inline] __irq_exit_rcu+0xf4/0x1c0 kernel/softirq.c:637 irq_exit_rcu+0x9/0x30 kernel/softirq.c:649 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1049 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:raw_spin_rq_unlock_irq+0x19/0x90 kernel/sched/sched.h:1518 Code: 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 41 57 41 56 53 48 89 fb 66 90 48 89 df e8 ae 85 6b 0a e8 89 42 37 00 fb 5b <41> 5e 41 5f c3 cc cc cc cc f3 0f 1e fa 49 bf 00 00 00 00 00 fc ff RSP: 0018:ffffc90000157b08 EFLAGS: 00000286 RAX: 31e3bfb087a32100 RBX: ffff8880b863ea80 RCX: ffffffff9a3d4903 RDX: dffffc0000000000 RSI: ffffffff8c0acac0 RDI: ffffffff8c610860 RBP: ffffc90000157d30 R08: ffffffff901d09af R09: 1ffffffff203a135 R10: dffffc0000000000 R11: fffffbfff203a136 R12: ffff8880b863ea80 R13: 0000000000000000 R14: ffff88801ceb5a00 R15: 0000000000000000 __schedule+0x1a69/0x4bd0 kernel/sched/core.c:6694 preempt_schedule_common+0x84/0xd0 kernel/sched/core.c:6869 preempt_schedule+0xe1/0xf0 kernel/sched/core.c:6893 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk.S:12 smpboot_thread_fn+0x65b/0xa30 kernel/smpboot.c:163 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244