rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-....: (1 GPs behind) idle=af3c/1/0x4000000000000000 softirq=37466/37467 fqs=2435 rcu: hardirqs softirqs csw/system rcu: number: 1398621 0 0 rcu: cputime: 13354 32576 36 ==> 45970(ms) rcu: (t=10504 jiffies g=39621 q=1788 ncpus=2) CPU: 0 PID: 10838 Comm: syz.2.1645 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:check_kcov_mode kernel/kcov.c:182 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x2e/0x60 kernel/kcov.c:216 Code: 48 8b 04 24 65 48 8b 0d 90 a2 7c 7e 65 8b 15 91 a2 7c 7e 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 1c 16 00 00 00 <74> 2c 8b 91 f8 15 00 00 83 fa 02 75 21 48 8b 91 00 16 00 00 48 8b RSP: 0018:ffffc90000005f18 EFLAGS: 00000246 RAX: ffffffff813b6c79 RBX: ffffc90000006150 RCX: ffff888043cf3c00 RDX: 0000000000000100 RSI: 0000000000000002 RDI: ffffc90000006150 RBP: ffffc90000006150 R08: ffff888043cf3c00 R09: 0000000000000003 R10: 0000000000000004 R11: 0000000000000100 R12: ffffc90000008000 R13: 1ffff92000000c1b R14: ffffc90000000000 R15: dffffc0000000000 FS: 00007f47df9f56c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000100000000 CR3: 000000002380b000 CR4: 00000000003506f0 DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: __read_once_word_nocheck+0x9/0x10 include/asm-generic/rwonce.h:66 deref_stack_reg+0x1bd/0x240 arch/x86/kernel/unwind_orc.c:406 unwind_next_frame+0x1789/0x2970 arch/x86/kernel/unwind_orc.c:648 __unwind_start+0x66a/0x7e0 arch/x86/kernel/unwind_orc.c:760 unwind_start arch/x86/include/asm/unwind.h:64 [inline] arch_stack_walk+0xf8/0x190 arch/x86/kernel/stacktrace.c:24 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+0xf8/0x270 mm/slub.c:3852 packet_rcv+0x16b/0x13d0 net/packet/af_packet.c:2278 dev_queue_xmit_nit+0xb16/0xbb0 net/core/dev.c:2398 xmit_one net/core/dev.c:3641 [inline] dev_hard_start_xmit+0x148/0x740 net/core/dev.c:3661 sch_direct_xmit+0x25e/0x4c0 net/sched/sch_generic.c:345 __dev_xmit_skb net/core/dev.c:3882 [inline] __dev_queue_xmit+0x179c/0x36b0 net/core/dev.c:4417 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+0x1cbd/0x32f0 net/ipv4/tcp_output.c:1422 tcp_rcv_established+0x1307/0x1d20 net/ipv4/tcp_input.c:6134 tcp_v4_do_rcv+0x4ed/0xb80 net/ipv4/tcp_ipv4.c:1734 tcp_v4_rcv+0x23bf/0x2af0 net/ipv4/tcp_ipv4.c:2166 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:5681 [inline] __netif_receive_skb_list_core+0x583/0x750 net/core/dev.c:5729 __netif_receive_skb_list net/core/dev.c:5781 [inline] netif_receive_skb_list_internal+0x943/0xca0 net/core/dev.c:5872 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:573 [inline] napi_gro_receive+0x565/0xb00 net/core/gro.c:603 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:6642 napi_poll net/core/dev.c:6709 [inline] net_rx_action+0x616/0xc50 net/core/dev.c:6846 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:trace_lock_release include/trace/events/lock.h:69 [inline] RIP: 0010:lock_release+0x809/0x8c0 kernel/locking/lockdep.c:5765 Code: 8f 76 00 48 0f a3 1d 0e 2d 22 0d 49 bd 00 00 00 00 00 fc ff df 4c 8b 7c 24 08 4d 89 f4 0f 83 bb f8 ff ff 65 ff 05 cf 08 9b 7e <48> c7 c0 48 cc 75 8e 48 c1 e8 03 42 80 3c 28 00 74 0c 48 c7 c7 48 RSP: 0018:ffffc9000c307b20 EFLAGS: 00000283 RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff8168acd2 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8e8ad9e8 RBP: ffffc9000c307c30 R08: ffffffff8e8ad9ef R09: 1ffffffff1d15b3d R10: dffffc0000000000 R11: fffffbfff1d15b3e R12: ffffffff81af14f8 R13: dffffc0000000000 R14: ffffffff81af14f8 R15: 1ffff92001860f70 __mutex_unlock_slowpath+0xcc/0x6c0 kernel/locking/mutex.c:907 __do_sys_perf_event_open kernel/events/core.c:12927 [inline] __se_sys_perf_event_open+0x19b8/0x1c50 kernel/events/core.c:12567 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f47deb9acb9 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:00007f47df9f5028 EFLAGS: 00000246 ORIG_RAX: 000000000000012a RAX: ffffffffffffffda RBX: 00007f47dee15fa0 RCX: 00007f47deb9acb9 RDX: ffffffffffffffff RSI: 0000000000000000 RDI: 0000200000000480 RBP: 00007f47dec08bf7 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000 R13: 00007f47dee16038 R14: 00007f47dee15fa0 R15: 00007ffdfe8eb638