rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5905/1:b..l P5863/1:b..l rcu: (detected by 0, t=10503 jiffies, g=8849, q=1272210 ncpus=2) task:syz.1.185 state:R running task stack:22752 pid:5863 tgid:5859 ppid:5230 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5322 [inline] __schedule+0x1895/0x4b30 kernel/sched/core.c:6682 preempt_schedule_irq+0xfb/0x1c0 kernel/sched/core.c:7004 irqentry_exit+0x5e/0x90 kernel/entry/common.c:354 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:get_stack_info+0x54/0xf0 arch/x86/kernel/dumpstack_64.c:208 Code: 03 00 48 85 ff 74 40 48 89 ee 48 89 da e8 c4 fe 92 0a 84 c0 74 31 45 31 ff 4d 85 f6 74 35 4d 8b 2e 44 8b 23 49 83 fc 40 73 52 <4d> 0f a3 e5 73 66 65 48 8b 04 25 00 d8 03 00 48 39 c5 75 09 80 3d RSP: 0018:ffffc90016e1f488 EFLAGS: 00000283 RAX: 0000000016e1f501 RBX: ffffc90016e1f520 RCX: ffffc90016e18000 RDX: ffffc90016e1f520 RSI: ffffc90016e20000 RDI: ffffc90016e1f4c0 RBP: ffff88802a6a0000 R08: ffffc90016e1f501 R09: 0000000000000000 R10: ffffc90016e1f520 R11: fffff52002dc3eb0 R12: 0000000000000001 R13: 0000000000000000 R14: ffffc90016e1f540 R15: 0000000000000000 __unwind_start+0x434/0x740 arch/x86/kernel/unwind_orc.c:729 unwind_start arch/x86/include/asm/unwind.h:64 [inline] arch_stack_walk+0xe5/0x150 arch/x86/kernel/stacktrace.c:24 stack_trace_save+0x118/0x1d0 kernel/stacktrace.c:122 save_stack+0xfb/0x1f0 mm/page_owner.c:156 __reset_page_owner+0x76/0x430 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+0xcfb/0xf20 mm/page_alloc.c:2638 __slab_free+0x31b/0x3d0 mm/slub.c:4490 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x23/0x80 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+0x135/0x2a0 mm/slub.c:4141 taskstats_tgid_alloc kernel/taskstats.c:582 [inline] taskstats_exit+0x360/0xa60 kernel/taskstats.c:621 do_exit+0x9ad/0x28e0 kernel/exit.c:924 do_group_exit+0x207/0x2c0 kernel/exit.c:1088 get_signal+0x16a3/0x1740 kernel/signal.c:2917 arch_do_signal_or_restart+0x96/0x860 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:328 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0xc9/0x370 kernel/entry/common.c:218 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fa96c57dff9 RSP: 002b:00007fa96d386038 EFLAGS: 00000246 ORIG_RAX: 000000000000002a RAX: fffffffffffffe00 RBX: 00007fa96c735f80 RCX: 00007fa96c57dff9 RDX: 0000000000000010 RSI: 0000000020000000 RDI: 0000000000000004 RBP: 00007fa96c5f0296 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fa96c735f80 R15: 00007ffe24f34538 task:syz.4.197 state:R running task stack:24896 pid:5905 tgid:5901 ppid:5238 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5322 [inline] __schedule+0x1895/0x4b30 kernel/sched/core.c:6682 preempt_schedule_common+0x84/0xd0 kernel/sched/core.c:6861 preempt_schedule+0xe1/0xf0 kernel/sched/core.c:6885 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_unlock+0x3e/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] zap_pte_range mm/memory.c:1691 [inline] zap_pmd_range mm/memory.c:1739 [inline] zap_pud_range mm/memory.c:1768 [inline] zap_p4d_range mm/memory.c:1789 [inline] unmap_page_range+0x36b1/0x40e0 mm/memory.c:1810 unmap_vmas+0x3cc/0x5f0 mm/memory.c:1900 exit_mmap+0x275/0xc40 mm/mmap.c:1864 __mmput+0x115/0x390 kernel/fork.c:1347 exit_mm+0x220/0x310 kernel/exit.c:571 do_exit+0x9b2/0x28e0 kernel/exit.c:926 do_group_exit+0x207/0x2c0 kernel/exit.c:1088 get_signal+0x16a3/0x1740 kernel/signal.c:2917 arch_do_signal_or_restart+0x96/0x860 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:328 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0xc9/0x370 kernel/entry/common.c:218 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f77fdd7dff9 RSP: 002b:00007f77feb0d0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007f77fdf35f88 RCX: 00007f77fdd7dff9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f77fdf35f88 RBP: 00007f77fdf35f80 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f77fdf35f8c R13: 0000000000000000 R14: 00007fff25eda180 R15: 00007fff25eda268 rcu: rcu_preempt kthread starved for 9334 jiffies! g8849 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:25816 pid:17 tgid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5322 [inline] __schedule+0x1895/0x4b30 kernel/sched/core.c:6682 __schedule_loop kernel/sched/core.c:6759 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6774 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: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 25 Comm: kworker/1:0 Not tainted 6.12.0-rc2-syzkaller-00631-g6d858708d465 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Workqueue: events nsim_dev_trap_report_work RIP: 0010:validate_chain+0xcc/0x5920 kernel/locking/lockdep.c:3871 Code: 4a 89 44 21 1f 48 b8 f2 f2 f2 f2 f2 00 f3 f3 4a 89 44 21 2b 48 89 8c 24 c0 00 00 00 42 c6 44 21 33 f3 48 89 b4 24 b0 00 00 00 <4c> 8d 6e 20 4c 89 e8 48 c1 e8 03 48 89 44 24 60 42 0f b6 04 20 84 RSP: 0018:ffffc90000a177c0 EFLAGS: 00000806 RAX: f3f300f2f2f2f2f2 RBX: ffffffff93c46190 RCX: 1ffff92000142f18 RDX: 0000000000000000 RSI: ffff88801d2f29f8 RDI: ffff88801d2f1e00 RBP: ffffc90000a17ac0 R08: ffffffff942cc807 R09: 1ffffffff2859900 R10: dffffc0000000000 R11: fffffbfff2859901 R12: dffffc0000000000 R13: ffff88801d2f28d8 R14: 0c820981093c63e6 R15: ffff88801d2f2a18 FS: 0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000557622e3f000 CR3: 000000000e734000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __lock_acquire+0x1384/0x2050 kernel/locking/lockdep.c:5202 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825 rcu_lock_acquire include/linux/rcupdate.h:337 [inline] rcu_read_lock include/linux/rcupdate.h:849 [inline] net_generic include/net/netns/generic.h:45 [inline] synproxy_pernet+0x40/0x240 include/net/netfilter/nf_synproxy.h:32 ipv4_synproxy_hook+0xb5/0x1040 net/netfilter/nf_synproxy_core.c:643 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 NF_HOOK_COND include/linux/netfilter.h:302 [inline] ip_output+0x185/0x230 net/ipv4/ip_output.c:434 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:5668 [inline] __netif_receive_skb+0x2bf/0x650 net/core/dev.c:5781 process_backlog+0x662/0x15b0 net/core/dev.c:6113 __napi_poll+0xcb/0x490 net/core/dev.c:6834 napi_poll net/core/dev.c:6903 [inline] net_rx_action+0x89b/0x1240 net/core/dev.c:7025 handle_softirqs+0x2c5/0x980 kernel/softirq.c:554 do_softirq+0x11b/0x1e0 kernel/softirq.c:455 __local_bh_enable_ip+0x1bb/0x200 kernel/softirq.c:382 spin_unlock_bh include/linux/spinlock.h:396 [inline] nsim_dev_trap_report drivers/net/netdevsim/dev.c:820 [inline] nsim_dev_trap_report_work+0x75d/0xaa0 drivers/net/netdevsim/dev.c:850 process_one_work kernel/workqueue.c:3229 [inline] process_scheduled_works+0xa63/0x1850 kernel/workqueue.c:3310 worker_thread+0x870/0xd30 kernel/workqueue.c:3391 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