rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-....: (1 GPs behind) idle=1224/1/0x4000000000000000 softirq=33989/33990 fqs=2021 rcu: hardirqs softirqs csw/system rcu: number: 1332265 0 0 rcu: cputime: 14966 37523 42 ==> 52520(ms) rcu: (t=10505 jiffies g=41309 q=2964 ncpus=2) CPU: 0 PID: 10783 Comm: syz.0.1727 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:__sanitizer_cov_trace_cmp8+0x7e/0x80 kernel/kcov.c:294 Code: c1 e1 05 4c 8d 51 28 4d 39 ca 77 1e 49 ff c0 4c 89 02 48 c7 44 0a 08 06 00 00 00 48 89 7c 0a 10 48 89 74 0a 18 48 89 44 0a 20 90 f3 0f 1e fa 48 8b 04 24 65 48 8b 15 10 88 7c 7e 65 8b 0d 11 RSP: 0018:ffffc90000005e30 EFLAGS: 00000246 RAX: ffffffff813b3c78 RBX: ffffffff8f06eb8c RCX: ffff888022c41e00 RDX: 0000000000000100 RSI: ffffffff8aa01449 RDI: ffffffff8aa01442 RBP: ffffffff8f06eb80 R08: ffffc90000005fd0 R09: 0000000000000024 R10: 0000000000000004 R11: 0000000000000100 R12: ffffffff8f06eb84 R13: ffffffff8aa01442 R14: ffffffff8aa01449 R15: ffffffff8f06eb88 FS: 00007ffa1a8c36c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000100000000 CR3: 000000005ae4e000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: __orc_find arch/x86/kernel/unwind_orc.c:102 [inline] orc_find arch/x86/kernel/unwind_orc.c:227 [inline] unwind_next_frame+0x4b8/0x2970 arch/x86/kernel/unwind_orc.c:494 arch_stack_walk+0x144/0x190 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xaa/0x100 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4e/0x70 mm/kasan/common.c:53 kasan_save_free_info+0x2e/0x50 mm/kasan/generic.c:522 ____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:237 kasan_slab_free include/linux/kasan.h:164 [inline] slab_free_hook mm/slub.c:1811 [inline] slab_free_freelist_hook+0x130/0x1a0 mm/slub.c:1837 slab_free mm/slub.c:3830 [inline] __kmem_cache_free+0xba/0x1e0 mm/slub.c:3843 skb_kfree_head net/core/skbuff.c:946 [inline] skb_free_head net/core/skbuff.c:958 [inline] skb_release_data+0x5dc/0x7b0 net/core/skbuff.c:988 skb_release_all net/core/skbuff.c:1054 [inline] __kfree_skb net/core/skbuff.c:1068 [inline] kfree_skb_reason+0x10e/0x170 net/core/skbuff.c:1104 dev_kfree_skb_any_reason+0x120/0x130 net/core/dev.c:3241 free_old_xmit_skbs+0x11a/0x3d0 drivers/net/virtio_net.c:780 start_xmit+0x168/0x14a0 drivers/net/virtio_net.c:2420 __netdev_start_xmit include/linux/netdevice.h:4943 [inline] netdev_start_xmit include/linux/netdevice.h:4957 [inline] xmit_one net/core/dev.c:3644 [inline] dev_hard_start_xmit+0x246/0x740 net/core/dev.c:3660 sch_direct_xmit+0x25e/0x4c0 net/sched/sch_generic.c:345 __dev_xmit_skb net/core/dev.c:3881 [inline] __dev_queue_xmit+0x165d/0x3660 net/core/dev.c:4416 dev_queue_xmit include/linux/netdevice.h:3113 [inline] neigh_hh_output include/net/neighbour.h:527 [inline] neigh_output include/net/neighbour.h:541 [inline] ip_finish_output2+0xcec/0x11e0 net/ipv4/ip_output.c:235 NF_HOOK_COND include/linux/netfilter.h:293 [inline] ip_output+0x2a1/0x3b0 net/ipv4/ip_output.c:436 dst_output include/net/dst.h:467 [inline] ip_local_out net/ipv4/ip_output.c:129 [inline] __ip_queue_xmit+0x1049/0x1950 net/ipv4/ip_output.c:540 __tcp_transmit_skb+0x1d6d/0x33f0 net/ipv4/tcp_output.c:1427 tcp_rcv_established+0x1307/0x1d20 net/ipv4/tcp_input.c:6144 tcp_v4_do_rcv+0x4ed/0xb80 net/ipv4/tcp_ipv4.c:1735 tcp_v4_rcv+0x23bf/0x2af0 net/ipv4/tcp_ipv4.c:2167 ip_protocol_deliver_rcu+0x20e/0x3f0 net/ipv4/ip_input.c:205 ip_local_deliver_finish+0x2ca/0x510 net/ipv4/ip_input.c:233 NF_HOOK+0x32d/0x3b0 include/linux/netfilter.h:304 dst_input include/net/dst.h:477 [inline] ip_sublist_rcv_finish net/ipv4/ip_input.c:580 [inline] ip_list_rcv_finish net/ipv4/ip_input.c:631 [inline] ip_sublist_rcv+0xa4c/0xd70 net/ipv4/ip_input.c:639 ip_list_rcv+0x3f2/0x440 net/ipv4/ip_input.c:674 __netif_receive_skb_list_ptype net/core/dev.c:5689 [inline] __netif_receive_skb_list_core+0x583/0x750 net/core/dev.c:5737 __netif_receive_skb_list net/core/dev.c:5789 [inline] netif_receive_skb_list_internal+0x943/0xca0 net/core/dev.c:5880 gro_normal_list include/net/gro.h:451 [inline] gro_normal_one include/net/gro.h:464 [inline] napi_skb_finish net/core/gro.c:580 [inline] napi_gro_receive+0x565/0xb00 net/core/gro.c:610 receive_buf+0x2203/0x3820 drivers/net/virtio_net.c:1870 virtnet_receive drivers/net/virtio_net.c:2155 [inline] virtnet_poll+0x5dd/0x1280 drivers/net/virtio_net.c:2229 __napi_poll+0xc0/0x460 net/core/dev.c:6650 napi_poll net/core/dev.c:6717 [inline] net_rx_action+0x616/0xc40 net/core/dev.c:6853 handle_softirqs+0x280/0x820 kernel/softirq.c:578 __do_softirq kernel/softirq.c:612 [inline] invoke_softirq kernel/softirq.c:452 [inline] __irq_exit_rcu+0xd3/0x190 kernel/softirq.c:661 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline] sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:finish_task_switch+0x26a/0x8f0 kernel/sched/core.c:5255 Code: 0f 84 33 01 00 00 48 85 db 0f 85 52 01 00 00 0f 1f 44 00 00 4c 8b 75 d0 4c 89 e7 e8 e0 94 34 09 e8 1b 2f 30 00 fb 4c 8b 65 c0 <49> 8d bc 24 f8 15 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 28 84 c0 RSP: 0018:ffffc9000c4f75b8 EFLAGS: 00000286 RAX: b8017d97c98f9000 RBX: 0000000000000000 RCX: b8017d97c98f9000 RDX: dffffc0000000000 RSI: ffffffff8acacbe0 RDI: ffffffff8b1c9c20 RBP: ffffc9000c4f7610 R08: ffffffff8e8b666f R09: 1ffffffff1d16ccd R10: dffffc0000000000 R11: fffffbfff1d16cce R12: ffff888022c41e00 R13: dffffc0000000000 R14: ffffffff8ce93440 R15: ffff8880b8e3cb48 context_switch kernel/sched/core.c:5384 [inline] __schedule+0x155b/0x45a0 kernel/sched/core.c:6700 preempt_schedule_irq+0xbf/0x150 kernel/sched/core.c:7010 irqentry_exit+0x67/0x70 kernel/entry/common.c:438 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:692 RIP: 0010:acct_update_integrals+0x394/0x3f0 kernel/tsacct.c:161 Code: 58 fe ff eb 1f e8 dc 58 fe ff e9 32 fe ff ff e8 d2 58 fe ff e8 bd 88 ff 08 4d 85 f6 74 e0 e8 c3 58 fe ff fb 43 c6 44 25 10 f8 <43> c6 44 25 0c f8 48 c7 44 24 20 0e 36 e0 45 4b c7 44 25 00 00 00 RSP: 0018:ffffc9000c4f79a0 EFLAGS: 00000293 RAX: ffffffff8188d2cd RBX: 0000000000000000 RCX: ffff888022c41e00 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc9000c4f7ab0 R08: ffffffff8e8b666f R09: 1ffffffff1d16ccd R10: dffffc0000000000 R11: fffffbfff1d16cce R12: dffffc0000000000 R13: 1ffff9200189ef38 R14: 0000000000000200 R15: 000000000005b5e1 do_exit+0x606/0x2460 kernel/exit.c:836 do_group_exit+0x21b/0x2d0 kernel/exit.c:1026 get_signal+0x12fc/0x13f0 kernel/signal.c:2902 arch_do_signal_or_restart+0xc2/0x800 arch/x86/kernel/signal.c:310 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline] syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302 do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7ffa1999ce59 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffa1a8c30e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: 0000000000000001 RBX: 00007ffa19c15fa8 RCX: 00007ffa1999ce59 RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007ffa19c15fac RBP: 00007ffa19c15fa0 R08: 0000000000745a4d R09: 0000000000000000 R10: 0000000000000009 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffa19c16038 R14: 00007ffe3f901350 R15: 00007ffe3f901438