rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5726/1:b..l rcu: (detected by 1, t=10502 jiffies, g=15061, q=1445746 ncpus=2) task:syz.4.59 state:R running task stack:25656 pid:5726 tgid:5718 ppid:5373 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:lockdep_enabled kernel/locking/lockdep.c:122 [inline] RIP: 0010:lock_release+0x12a/0xa30 kernel/locking/lockdep.c:5838 Code: 7e 85 c0 0f 85 46 05 00 00 65 48 8b 04 25 00 d8 03 00 48 89 44 24 20 48 8d 98 dc 0a 00 00 48 89 d8 48 c1 e8 03 42 0f b6 04 38 <84> c0 0f 85 fb 05 00 00 83 3b 00 0f 85 14 05 00 00 4c 89 f0 48 c1 RSP: 0018:ffffc900037f71e0 EFLAGS: 00000a07 RAX: 0000000000000000 RBX: ffff88802cb628dc RCX: ffffffff81707dc0 RDX: 0000000000000000 RSI: ffffffff8c60fb00 RDI: ffffffff8c60fac0 RBP: ffffc900037f7318 R08: ffffffff901d11af R09: 1ffffffff203a235 R10: dffffc0000000000 R11: fffffbfff203a236 R12: 1ffff920006fee48 R13: ffffffff820b6857 R14: ffffffff8e937de0 R15: dffffc0000000000 rcu_lock_release include/linux/rcupdate.h:347 [inline] rcu_read_unlock include/linux/rcupdate.h:880 [inline] page_ext_put+0xa3/0xc0 mm/page_ext.c:550 page_table_check_alloc include/linux/page_table_check.h:33 [inline] post_alloc_hook+0x206/0x230 mm/page_alloc.c:1538 prep_new_page mm/page_alloc.c:1545 [inline] get_page_from_freelist+0x3045/0x3190 mm/page_alloc.c:3457 __alloc_pages_noprof+0x292/0x710 mm/page_alloc.c:4733 alloc_pages_mpol_noprof+0x3e8/0x680 mm/mempolicy.c:2265 folio_alloc_mpol_noprof+0x36/0x50 mm/mempolicy.c:2283 shmem_alloc_folio mm/shmem.c:1774 [inline] shmem_alloc_and_add_folio+0x49b/0x13d0 mm/shmem.c:1813 shmem_get_folio_gfp+0x5a9/0x20a0 mm/shmem.c:2335 shmem_get_folio mm/shmem.c:2441 [inline] shmem_write_begin+0x17e/0x460 mm/shmem.c:3046 generic_perform_write+0x344/0x6d0 mm/filemap.c:4054 shmem_file_write_iter+0xf9/0x120 mm/shmem.c:3221 new_sync_write fs/read_write.c:590 [inline] vfs_write+0xa6d/0xc90 fs/read_write.c:683 ksys_write+0x183/0x2b0 fs/read_write.c:736 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f50b557dff9 RSP: 002b:00007f50b6393038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f50b5736208 RCX: 00007f50b557dff9 RDX: 00000000ffffff6a RSI: 0000000020000000 RDI: 0000000000000009 RBP: 00007f50b55f0296 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f50b5736208 R15: 00007ffd4ad3ae58 rcu: rcu_preempt kthread starved for 10547 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:25136 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: CPU: 1 UID: 0 PID: 51 Comm: kworker/1:1 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:__orc_find arch/x86/kernel/unwind_orc.c:99 [inline] RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:227 [inline] RIP: 0010:unwind_next_frame+0x6f6/0x22d0 arch/x86/kernel/unwind_orc.c:494 Code: 00 00 fc ff df 0f b6 04 08 84 c0 75 27 48 63 03 48 01 d8 48 8d 4b 04 4c 39 f8 4c 0f 46 f1 48 8d 43 fc 48 0f 47 e8 4c 0f 46 e3 <49> 39 ee 76 a9 e9 55 fb ff ff 89 d9 80 e1 07 80 c1 03 38 c1 7c cd RSP: 0018:ffffc90000a17bb0 EFLAGS: 00000216 RAX: ffffffff9035793c RBX: ffffffff90357940 RCX: ffffffff90357944 RDX: 00000000000b0001 RSI: ffffffff90aec976 RDI: 0000000000000001 RBP: ffffffff9035793c R08: 0000000000000009 R09: ffffc90000a17d70 R10: ffffc90000a17cd0 R11: ffffffff8180a0e0 R12: ffffffff90357930 R13: ffffffff90357930 R14: ffffffff90357930 R15: ffffffff81f2884f FS: 0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020dff000 CR3: 000000006746c000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: 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 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:579 poison_slab_object mm/kasan/common.c:247 [inline] __kasan_slab_free+0x59/0x70 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+0x1a0/0x440 mm/slub.c:4727 skb_kfree_head net/core/skbuff.c:1086 [inline] skb_free_head net/core/skbuff.c:1098 [inline] skb_release_data+0x6a0/0x8a0 net/core/skbuff.c:1125 skb_release_all net/core/skbuff.c:1190 [inline] __kfree_skb net/core/skbuff.c:1204 [inline] consume_skb+0x9f/0xf0 net/core/skbuff.c:1436 nft_synproxy_eval_v4+0x3d2/0x610 net/netfilter/nft_synproxy.c:60 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