watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [syz.3.1282:10210] Modules linked in: irq event stamp: 5563 hardirqs last enabled at (5562): [] irqentry_exit_to_kernel_mode_after_preempt include/linux/irq-entry-common.h:507 [inline] hardirqs last enabled at (5562): [] arm64_exit_to_kernel_mode+0x80/0x94 arch/arm64/kernel/entry-common.c:62 hardirqs last disabled at (5563): [] __el1_irq arch/arm64/kernel/entry-common.c:506 [inline] hardirqs last disabled at (5563): [] el1_interrupt+0x28/0x60 arch/arm64/kernel/entry-common.c:522 softirqs last enabled at (778): [] __alloc_skb+0x1c0/0x610 net/core/skbuff.c:698 softirqs last disabled at (780): [] local_bh_disable include/linux/bottom_half.h:20 [inline] softirqs last disabled at (780): [] rcu_read_lock_bh include/linux/rcupdate.h:893 [inline] softirqs last disabled at (780): [] __dev_queue_xmit+0x1fc/0x2bc0 net/core/dev.c:4796 CPU: 0 UID: 0 PID: 10210 Comm: syz.3.1282 Tainted: G L syzkaller #0 PREEMPT Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/02/2026 pstate: 43400005 (nZcv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=--) pc : check_kcov_mode+0x44/0x54 kernel/kcov.c:185 lr : __sanitizer_cov_trace_pc+0x28/0x5c kernel/kcov.c:217 sp : ffff800097546f40 x29: ffff800097546f40 x28: ffff00011d5bb8c0 x27: dfff800000000000 x26: 0000000000000008 x25: dfff800000000000 x24: ffff0000d0fec100 x23: ffff0000f94e1d40 x22: ffff800086cf89c0 x21: ffff8000878ca080 x20: ffff0000f94e1d40 x19: ffff80008199cab8 x18: 0000000000000000 x17: 0000000000000000 x16: 0000000000000000 x15: 00000000200022c0 x14: 00000000ffff8000 x13: 00000000fff10000 x12: ffff0000f3007290 x11: 0000000000000000 x10: 0000000000080000 x9 : 0000000000000200 x8 : ffff0000f94e1d40 x7 : 00000000fff10000 x6 : ffff0000f3007290 x5 : ffff800097547150 x4 : 0000000000000000 x3 : ffff800084f8e3c8 x2 : 0000000000000001 x1 : ffff0000f94e1d40 x0 : 0000000000000002 Call trace: check_kcov_mode+0x44/0x54 kernel/kcov.c:183 (P) preempt_count+0x14/0x68 arch/arm64/include/asm/preempt.h:11 check_preemption_disabled+0x30/0xe0 lib/smp_processor_id.c:16 __this_cpu_preempt_check+0x1c/0x28 lib/smp_processor_id.c:64 basic_classify+0xc0/0x310 net/sched/cls_basic.c:49 tc_classify include/net/tc_wrapper.h:260 [inline] __tcf_classify net/sched/cls_api.c:1764 [inline] tcf_classify+0x448/0xdc0 net/sched/cls_api.c:1860 hfsc_classify net/sched/sch_hfsc.c:1146 [inline] hfsc_enqueue+0x2b4/0xd3c net/sched/sch_hfsc.c:1545 dev_qdisc_enqueue+0x60/0x450 net/core/dev.c:4179 __dev_xmit_skb net/core/dev.c:4294 [inline] __dev_queue_xmit+0x13f0/0x2bc0 net/core/dev.c:4836 dev_queue_xmit include/linux/netdevice.h:3446 [inline] packet_xmit+0x6c/0x314 net/packet/af_packet.c:276 packet_snd net/packet/af_packet.c:3082 [inline] packet_sendmsg+0x319c/0x4110 net/packet/af_packet.c:3114 sock_sendmsg_nosec net/socket.c:775 [inline] __sock_sendmsg+0xc8/0x17c net/socket.c:790 ____sys_sendmsg+0x3d0/0x6c8 net/socket.c:2684 ___sys_sendmsg+0x198/0x224 net/socket.c:2738 __sys_sendmsg+0x158/0x204 net/socket.c:2770 __do_sys_sendmsg net/socket.c:2775 [inline] __se_sys_sendmsg net/socket.c:2773 [inline] __arm64_sys_sendmsg+0x80/0x94 net/socket.c:2773 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49 el0_svc_common+0xec/0x23c arch/arm64/kernel/syscall.c:121 do_el0_svc+0x4c/0x5c arch/arm64/kernel/syscall.c:140 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:736 el0t_64_sync_handler+0x48/0x148 arch/arm64/kernel/entry-common.c:755 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:594 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 skipped: idling at __daif_local_irq_enable arch/arm64/include/asm/irqflags.h:26 [inline] NMI backtrace for cpu 1 skipped: idling at arch_local_irq_enable arch/arm64/include/asm/irqflags.h:48 [inline] NMI backtrace for cpu 1 skipped: idling at default_idle_call+0xd0/0xfc kernel/sched/idle.c:129