rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-....: (1 GPs behind) idle=6c7c/1/0x4000000000000000 softirq=225044/225045 fqs=5216 rcu: hardirqs softirqs csw/system rcu: number: 8160 0 0 rcu: cputime: 211 52268 5 ==> 52480(ms) rcu: (t=10500 jiffies g=207761 q=2616 ncpus=2) CPU: 0 UID: 0 PID: 8027 Comm: syz.0.10864 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:qdisc_peek_head+0x0/0x40 include/net/sch_generic.h:1180 Code: 4c 89 ff e8 52 c9 c3 f8 e9 95 fe ff ff 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 53 48 89 fb e8 93 a6 5d f8 48 81 c3 40 01 00 00 48 89 RSP: 0018:ffffc90000007c68 EFLAGS: 00000246 RAX: 1ffffffff1f05807 RBX: ffff88807af6e800 RCX: 0000000000000100 RDX: ffff88802595bd00 RSI: 0000000000000000 RDI: ffff88807af6e800 RBP: ffff88808d784000 R08: ffffffff89702936 R09: ffffffff8df41aa0 R10: 0000000000000001 R11: ffffffff89635210 R12: dffffc0000000000 R13: ffff888045fb8000 R14: ffff88807af6e800 R15: ffffffff8f82c038 FS: 00007f1cab5766c0(0000) GS:ffff888125e1c000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00002000000022c0 CR3: 0000000056290000 CR4: 00000000003526f0 Call Trace: taprio_dequeue_from_txq+0x174/0x980 net/sched/sch_taprio.c:726 taprio_dequeue_tc_priority+0x1ac/0x750 net/sched/sch_taprio.c:793 taprio_dequeue+0x186/0x550 net/sched/sch_taprio.c:-1 dequeue_skb net/sched/sch_generic.c:297 [inline] qdisc_restart net/sched/sch_generic.c:402 [inline] __qdisc_run+0x23f/0x1510 net/sched/sch_generic.c:420 qdisc_run+0xc7/0x300 include/net/pkt_sched.h:120 net_tx_action+0x717/0x900 net/core/dev.c:5795 handle_softirqs+0x22b/0x7c0 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0x60/0x150 kernel/softirq.c:723 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1056 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:console_flush_one_record arch/x86/include/asm/irqflags.h:-1 [inline] RIP: 0010:console_flush_all+0x7fc/0xb00 kernel/printk/printk.c:3289 Code: ff ff e8 b7 f9 1f 00 90 0f 0b 90 e9 85 fc ff ff e8 a9 f9 1f 00 e8 14 42 b9 09 48 85 db 74 c0 e8 9a f9 1f 00 fb 48 8b 5c 24 10 <48> 8b 44 24 20 42 80 3c 28 00 4c 8b 74 24 18 74 08 4c 89 f7 e8 6b RSP: 0018:ffffc9000b716fc0 EFLAGS: 00000283 RAX: ffffffff81a0ff16 RBX: ffffc9000b717120 RCX: 0000000000080000 RDX: ffffc90013cb5000 RSI: 0000000000002b2b RDI: 0000000000002b2c RBP: ffffc9000b7170d0 R08: ffffffff8f823877 R09: 1ffffffff1f0470e R10: dffffc0000000000 R11: fffffbfff1f0470f R12: 0000000000000001 R13: dffffc0000000000 R14: 0000000000000000 R15: ffffffff8e792280 __console_flush_and_unlock kernel/printk/printk.c:3319 [inline] console_unlock+0xbb/0x190 kernel/printk/printk.c:3359 vprintk_emit+0x47b/0x550 kernel/printk/printk.c:2426 _printk+0xcf/0x120 kernel/printk/printk.c:2451 validate_nla lib/nlattr.c:414 [inline] __nla_validate_parse+0x1719/0x2d40 lib/nlattr.c:635 __nla_validate+0x40/0x60 lib/nlattr.c:677 nlmsg_validate_deprecated include/net/netlink.h:931 [inline] rtm_to_fib_config+0x91/0x13c0 net/ipv4/fib_frontend.c:743 inet_rtm_newroute+0xf3/0x210 net/ipv4/fib_frontend.c:918 rtnetlink_rcv_msg+0x7cf/0xb70 net/core/rtnetlink.c:6958 netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2550 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg+0x21c/0x270 net/socket.c:742 __sys_sendto+0x3bd/0x520 net/socket.c:2206 __do_sys_sendto net/socket.c:2213 [inline] __se_sys_sendto net/socket.c:2209 [inline] __x64_sys_sendto+0xde/0x100 net/socket.c:2209 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f1caa78f749 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f1cab576038 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007f1caa9e5fa0 RCX: 00007f1caa78f749 RDX: 0000000000000078 RSI: 00002000000022c0 RDI: 0000000000000007 RBP: 00007f1caa813f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f1caa9e6038 R14: 00007f1caa9e5fa0 R15: 00007ffc833046c8 NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 8027 Comm: syz.0.10864 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:taprio_next_tc_txq net/sched/sch_taprio.c:765 [inline] RIP: 0010:taprio_dequeue_tc_priority+0x1bb/0x750 net/sched/sch_taprio.c:796 Code: a6 02 00 00 41 8b 75 00 48 8b 7c 24 48 48 8b 54 24 50 8b 4c 24 1c e8 b4 05 00 00 48 89 44 24 10 48 8b 44 24 58 42 0f b6 04 20 <84> c0 0f 85 96 02 00 00 48 8b 44 24 20 44 0f b7 30 48 8b 44 24 70 RSP: 0018:ffffc90000007cd8 EFLAGS: 00000286 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff88802595bd00 RDX: 0000000000000100 RSI: 0000000000000000 RDI: ffff88807af6e800 RBP: 1ffff11011af086a R08: ffffffff89702936 R09: ffffffff8df41aa0 R10: 0000000000000001 R11: ffffffff89635210 R12: dffffc0000000000 R13: ffff88808d784354 R14: 0000000000000010 R15: 0000000000000002 FS: 00007f1cab5766c0(0000) GS:ffff888125e1c000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00002000000022c0 CR3: 0000000056290000 CR4: 00000000003526f0 Call Trace: taprio_dequeue+0x186/0x550 net/sched/sch_taprio.c:-1 dequeue_skb net/sched/sch_generic.c:297 [inline] qdisc_restart net/sched/sch_generic.c:402 [inline] __qdisc_run+0x23f/0x1510 net/sched/sch_generic.c:420 qdisc_run+0xc7/0x300 include/net/pkt_sched.h:120 net_tx_action+0x717/0x900 net/core/dev.c:5795 handle_softirqs+0x22b/0x7c0 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0x60/0x150 kernel/softirq.c:723 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1056 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:console_flush_one_record arch/x86/include/asm/irqflags.h:-1 [inline] RIP: 0010:console_flush_all+0x7fc/0xb00 kernel/printk/printk.c:3289 Code: ff ff e8 b7 f9 1f 00 90 0f 0b 90 e9 85 fc ff ff e8 a9 f9 1f 00 e8 14 42 b9 09 48 85 db 74 c0 e8 9a f9 1f 00 fb 48 8b 5c 24 10 <48> 8b 44 24 20 42 80 3c 28 00 4c 8b 74 24 18 74 08 4c 89 f7 e8 6b RSP: 0018:ffffc9000b716fc0 EFLAGS: 00000283 RAX: ffffffff81a0ff16 RBX: ffffc9000b717120 RCX: 0000000000080000 RDX: ffffc90013cb5000 RSI: 0000000000002b2b RDI: 0000000000002b2c RBP: ffffc9000b7170d0 R08: ffffffff8f823877 R09: 1ffffffff1f0470e R10: dffffc0000000000 R11: fffffbfff1f0470f R12: 0000000000000001 R13: dffffc0000000000 R14: 0000000000000000 R15: ffffffff8e792280 __console_flush_and_unlock kernel/printk/printk.c:3319 [inline] console_unlock+0xbb/0x190 kernel/printk/printk.c:3359 vprintk_emit+0x47b/0x550 kernel/printk/printk.c:2426 _printk+0xcf/0x120 kernel/printk/printk.c:2451 validate_nla lib/nlattr.c:414 [inline] __nla_validate_parse+0x1719/0x2d40 lib/nlattr.c:635 __nla_validate+0x40/0x60 lib/nlattr.c:677 nlmsg_validate_deprecated include/net/netlink.h:931 [inline] rtm_to_fib_config+0x91/0x13c0 net/ipv4/fib_frontend.c:743 inet_rtm_newroute+0xf3/0x210 net/ipv4/fib_frontend.c:918 rtnetlink_rcv_msg+0x7cf/0xb70 net/core/rtnetlink.c:6958 netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2550 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg+0x21c/0x270 net/socket.c:742 __sys_sendto+0x3bd/0x520 net/socket.c:2206 __do_sys_sendto net/socket.c:2213 [inline] __se_sys_sendto net/socket.c:2209 [inline] __x64_sys_sendto+0xde/0x100 net/socket.c:2209 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f1caa78f749 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f1cab576038 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007f1caa9e5fa0 RCX: 00007f1caa78f749 RDX: 0000000000000078 RSI: 00002000000022c0 RDI: 0000000000000007 RBP: 00007f1caa813f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f1caa9e6038 R14: 00007f1caa9e5fa0 R15: 00007ffc833046c8 watchdog: BUG: soft lockup - CPU#0 stuck for 266s! [syz.0.10864:8027] Modules linked in: irq event stamp: 88215 hardirqs last enabled at (88214): [] irqentry_exit+0x5e8/0x670 kernel/entry/common.c:219 hardirqs last disabled at (88215): [] sysvec_apic_timer_interrupt+0xe/0xc0 arch/x86/kernel/apic/apic.c:1056 softirqs last enabled at (268): [] local_bh_disable include/linux/bottom_half.h:20 [inline] softirqs last enabled at (268): [] rcu_read_lock_bh include/linux/rcupdate.h:918 [inline] softirqs last enabled at (268): [] __dev_queue_xmit+0x280/0x3100 net/core/dev.c:4756 softirqs last disabled at (281): [] __do_softirq kernel/softirq.c:656 [inline] softirqs last disabled at (281): [] invoke_softirq kernel/softirq.c:496 [inline] softirqs last disabled at (281): [] __irq_exit_rcu+0x60/0x150 kernel/softirq.c:723 CPU: 0 UID: 0 PID: 8027 Comm: syz.0.10864 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x20/0x70 kernel/kcov.c:217 Code: 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 8b 04 24 65 48 8b 0c 25 08 40 80 92 65 8b 15 68 47 bf 10 81 e2 00 01 ff 00 74 11 <81> fa 00 01 00 00 75 35 83 b9 6c 16 00 00 00 74 2c 8b 91 48 16 00 RSP: 0018:ffffc90000007cd0 EFLAGS: 00000206 RAX: ffffffff8970d020 RBX: 0000000000000000 RCX: ffff88802595bd00 RDX: 0000000000000100 RSI: 0000000000000010 RDI: 0000000000000008 RBP: 1ffff11011af086a R08: ffffffff89702936 R09: ffffffff8df41aa0 R10: 0000000000000001 R11: ffffffff89635210 R12: dffffc0000000000 R13: ffff88808d784354 R14: 0000000000000010 R15: 0000000000000002 FS: 00007f1cab5766c0(0000) GS:ffff888125e1c000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00002000000022c0 CR3: 0000000056290000 CR4: 00000000003526f0 Call Trace: taprio_dequeue_tc_priority+0x2d0/0x750 net/sched/sch_taprio.c:803 taprio_dequeue+0x186/0x550 net/sched/sch_taprio.c:-1 dequeue_skb net/sched/sch_generic.c:297 [inline] qdisc_restart net/sched/sch_generic.c:402 [inline] __qdisc_run+0x23f/0x1510 net/sched/sch_generic.c:420 qdisc_run+0xc7/0x300 include/net/pkt_sched.h:120 net_tx_action+0x717/0x900 net/core/dev.c:5795 handle_softirqs+0x22b/0x7c0 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0x60/0x150 kernel/softirq.c:723 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1056 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:console_flush_one_record arch/x86/include/asm/irqflags.h:-1 [inline] RIP: 0010:console_flush_all+0x7fc/0xb00 kernel/printk/printk.c:3289 Code: ff ff e8 b7 f9 1f 00 90 0f 0b 90 e9 85 fc ff ff e8 a9 f9 1f 00 e8 14 42 b9 09 48 85 db 74 c0 e8 9a f9 1f 00 fb 48 8b 5c 24 10 <48> 8b 44 24 20 42 80 3c 28 00 4c 8b 74 24 18 74 08 4c 89 f7 e8 6b RSP: 0018:ffffc9000b716fc0 EFLAGS: 00000283 RAX: ffffffff81a0ff16 RBX: ffffc9000b717120 RCX: 0000000000080000 RDX: ffffc90013cb5000 RSI: 0000000000002b2b RDI: 0000000000002b2c RBP: ffffc9000b7170d0 R08: ffffffff8f823877 R09: 1ffffffff1f0470e R10: dffffc0000000000 R11: fffffbfff1f0470f R12: 0000000000000001 R13: dffffc0000000000 R14: 0000000000000000 R15: ffffffff8e792280 __console_flush_and_unlock kernel/printk/printk.c:3319 [inline] console_unlock+0xbb/0x190 kernel/printk/printk.c:3359 vprintk_emit+0x47b/0x550 kernel/printk/printk.c:2426 _printk+0xcf/0x120 kernel/printk/printk.c:2451 validate_nla lib/nlattr.c:414 [inline] __nla_validate_parse+0x1719/0x2d40 lib/nlattr.c:635 __nla_validate+0x40/0x60 lib/nlattr.c:677 nlmsg_validate_deprecated include/net/netlink.h:931 [inline] rtm_to_fib_config+0x91/0x13c0 net/ipv4/fib_frontend.c:743 inet_rtm_newroute+0xf3/0x210 net/ipv4/fib_frontend.c:918 rtnetlink_rcv_msg+0x7cf/0xb70 net/core/rtnetlink.c:6958 netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2550 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg+0x21c/0x270 net/socket.c:742 __sys_sendto+0x3bd/0x520 net/socket.c:2206 __do_sys_sendto net/socket.c:2213 [inline] __se_sys_sendto net/socket.c:2209 [inline] __x64_sys_sendto+0xde/0x100 net/socket.c:2209 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f1caa78f749 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f1cab576038 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007f1caa9e5fa0 RCX: 00007f1caa78f749 RDX: 0000000000000078 RSI: 00002000000022c0 RDI: 0000000000000007 RBP: 00007f1caa813f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f1caa9e6038 R14: 00007f1caa9e5fa0 R15: 00007ffc833046c8 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82 Code: cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 53 11 0e 00 f3 0f 1e fa fb f4 08 e3 02 00 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffc90000197e20 EFLAGS: 000002c6 RAX: 000000000047c991 RBX: ffffffff8197149e RCX: 0000000080000001 RDX: 0000000000000001 RSI: ffffffff8d794248 RDI: ffffffff8bc086e0 RBP: ffffc90000197f10 R08: ffff8880b87336db R09: 1ffff110170e66db R10: dffffc0000000000 R11: ffffed10170e66dc R12: ffffffff8f823870 R13: 1ffff110038dfb70 R14: 0000000000000001 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff888125f1c000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fc9caae249c CR3: 000000000dd3a000 CR4: 00000000003526f0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x73/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:191 [inline] do_idle+0x1be/0x4d0 kernel/sched/idle.c:332 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:430 start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:312 common_startup_64+0x13e/0x147