watchdog: BUG: soft lockup - CPU#0 stuck for 127s! [syz.7.120:6674] Modules linked in: irq event stamp: 21709085 hardirqs last enabled at (21709084): [] irqentry_exit+0x59c/0x620 kernel/entry/common.c:219 hardirqs last disabled at (21709085): [] sysvec_apic_timer_interrupt+0xe/0xc0 arch/x86/kernel/apic/apic.c:1056 softirqs last enabled at (21603030): [] __do_softirq kernel/softirq.c:656 [inline] softirqs last enabled at (21603030): [] invoke_softirq kernel/softirq.c:496 [inline] softirqs last enabled at (21603030): [] __irq_exit_rcu+0x5f/0x150 kernel/softirq.c:723 softirqs last disabled at (21603033): [] __do_softirq kernel/softirq.c:656 [inline] softirqs last disabled at (21603033): [] invoke_softirq kernel/softirq.c:496 [inline] softirqs last disabled at (21603033): [] __irq_exit_rcu+0x5f/0x150 kernel/softirq.c:723 CPU: 0 UID: 0 PID: 6674 Comm: syz.7.120 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 RIP: 0010:do_perf_trace_lock include/trace/events/lock.h:50 [inline] RIP: 0010:perf_trace_lock+0x32a/0x3f0 include/trace/events/lock.h:50 Code: 10 8b 94 24 80 00 00 00 4c 8b 4c 24 60 41 b8 01 00 00 00 44 89 f6 48 8b 4c 24 38 6a 00 ff 74 24 20 e8 5a aa 56 00 48 83 c4 10 <43> c6 44 27 08 f8 43 c6 44 27 04 f8 48 c7 44 24 40 0e 36 e0 45 4b RSP: 0018:ffffc90000007360 EFLAGS: 00000286 RAX: 6429b7a181867800 RBX: ffffe8ffffca4010 RCX: f8f8f8f8f8f8f8f8 RDX: 0000000000000100 RSI: 0000000000000001 RDI: 0000000000000002 RBP: ffffc90000007460 R08: ffffc90000007117 R09: 0000000000000000 R10: ffffc90000007108 R11: fffff52000000e23 R12: dffffc0000000000 R13: dffffc0000000000 R14: 000000000000002c R15: 1ffff92000000e74 FS: 00007f805bc336c0(0000) GS:ffff8881256f3000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb2e6d1f000 CR3: 000000003144e000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: __do_trace_lock_release include/trace/events/lock.h:69 [inline] trace_lock_release include/trace/events/lock.h:69 [inline] lock_release+0x379/0x3a0 kernel/locking/lockdep.c:5879 rcu_lock_release include/linux/rcupdate.h:341 [inline] rcu_read_unlock include/linux/rcupdate.h:897 [inline] class_rcu_destructor include/linux/rcupdate.h:1195 [inline] unwind_next_frame+0x1aaa/0x23c0 arch/x86/kernel/unwind_orc.c:695 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2540 [inline] slab_free mm/slub.c:6674 [inline] kmem_cache_free+0x195/0x610 mm/slub.c:6789 skb_kfree_head net/core/skbuff.c:1066 [inline] skb_free_head net/core/skbuff.c:1080 [inline] skb_release_data+0x688/0x8e0 net/core/skbuff.c:1107 skb_release_all net/core/skbuff.c:1182 [inline] napi_consume_skb+0x1d8/0x290 net/core/skbuff.c:1518 __free_old_xmit+0x2cd/0x680 drivers/net/virtio_net.c:-1 virtnet_free_old_xmit drivers/net/virtio_net.c:636 [inline] free_old_xmit drivers/net/virtio_net.c:1081 [inline] virtnet_poll_tx+0x457/0x16a0 drivers/net/virtio_net.c:3230 __napi_poll+0xae/0x340 net/core/dev.c:7681 napi_poll net/core/dev.c:7744 [inline] net_rx_action+0x627/0xf70 net/core/dev.c:7896 handle_softirqs+0x22a/0x7c0 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0x5f/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:perf_tp_event+0x28db/0x29b0 kernel/events/core.c:11114 Code: 28 08 00 00 00 00 4a c7 44 28 10 00 00 00 00 4a c7 44 28 18 00 00 00 00 4a c7 44 28 20 00 00 00 00 4a c7 44 28 28 00 00 00 00 <4a> c7 44 28 30 00 00 00 00 65 48 8b 05 64 5c fc 10 48 3b 84 24 40 RSP: 0018:ffffc90004a5f200 EFLAGS: 00000246 RAX: 1ffff9200094be50 RBX: ffff88803137efec RCX: f8f8f8f8f8f8f8f8 RDX: ffffc9001fe12000 RSI: 0000000000040e89 RDI: 0000000000040e8a RBP: ffffc90004a5f4c8 R08: ffffc90004a5f2d7 R09: 0000000000000000 R10: ffffc90004a5f2c8 R11: fffff5200094be5b R12: ffffe8ffffc98000 R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8880b8633178 perf_trace_run_bpf_submit+0xee/0x170 kernel/events/core.c:11014 do_perf_trace_lock include/trace/events/lock.h:50 [inline] perf_trace_lock+0x326/0x3f0 include/trace/events/lock.h:50 __do_trace_lock_release include/trace/events/lock.h:69 [inline] trace_lock_release include/trace/events/lock.h:69 [inline] lock_release+0x379/0x3a0 kernel/locking/lockdep.c:5879 rcu_lock_release include/linux/rcupdate.h:341 [inline] rcu_read_unlock include/linux/rcupdate.h:897 [inline] is_bpf_text_address+0x28d/0x2b0 kernel/bpf/core.c:746 kernel_text_address+0xa5/0xe0 kernel/extable.c:125 __kernel_text_address+0xd/0x30 kernel/extable.c:79 unwind_get_return_address+0x4d/0x90 arch/x86/kernel/unwind_orc.c:385 arch_stack_walk+0xfb/0x150 arch/x86/kernel/stacktrace.c:26 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556 __call_rcu_common kernel/rcu/tree.c:3119 [inline] call_rcu+0xee/0x890 kernel/rcu/tree.c:3239 __dentry_kill+0x469/0x5e0 fs/dcache.c:689 shrink_kill+0xa9/0x2c0 fs/dcache.c:1147 shrink_dentry_list+0x2e0/0x5e0 fs/dcache.c:1174 shrink_dcache_sb+0x23f/0x3c0 fs/dcache.c:1295 reconfigure_super+0x62b/0x8a0 fs/super.c:1055 do_remount fs/namespace.c:3264 [inline] path_mount+0xdc5/0x10e0 fs/namespace.c:4014 do_mount fs/namespace.c:4035 [inline] __do_sys_mount fs/namespace.c:4224 [inline] __se_sys_mount+0x31d/0x420 fs/namespace.c:4201 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f805ad9af79 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:00007f805bc33028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007f805b016090 RCX: 00007f805ad9af79 RDX: 0000000000000000 RSI: 0000200000000040 RDI: 0000200000000000 RBP: 00007f805ae316e0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000bc0023 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f805b016128 R14: 00007f805b016090 R15: 00007ffe0cb1d228 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 5833 Comm: kworker/u9:4 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 Workqueue: hci0 hci_cmd_timeout RIP: 0010:io_serial_in+0x77/0xc0 drivers/tty/serial/8250/8250_port.c:400 Code: e8 ae ae 92 fc 44 89 f9 d3 e3 49 83 c6 40 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 4f fe fa fc 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f c3 cc cc cc cc cc 44 89 f9 80 e1 07 RSP: 0018:ffffc9000426f3f8 EFLAGS: 00000006 RAX: 1ffffffff3467005 RBX: 00000000000003f9 RCX: 0000000000000000 RDX: 00000000000003f9 RSI: 0000000000000000 RDI: 0000000000000020 RBP: ffffc9000426f590 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: ffffffff8531cb20 R12: dffffc0000000000 R13: dffffc0000000000 R14: ffffffff9a3382a0 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881257f3000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f67e326896c CR3: 000000003144e000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: serial_port_in include/linux/serial_core.h:806 [inline] serial8250_console_write+0x540/0x1ba0 drivers/tty/serial/8250/8250_port.c:3306 console_emit_next_record kernel/printk/printk.c:3129 [inline] console_flush_one_record kernel/printk/printk.c:3215 [inline] console_flush_all+0x718/0xb20 kernel/printk/printk.c:3289 __console_flush_and_unlock kernel/printk/printk.c:3319 [inline] console_unlock+0xd1/0x1c0 kernel/printk/printk.c:3359 vprintk_emit+0x485/0x560 kernel/printk/printk.c:2426 _printk+0xdd/0x130 kernel/printk/printk.c:2451 bt_err+0x121/0x180 net/bluetooth/lib.c:296 hci_cmd_timeout+0xd8/0x1e0 net/bluetooth/hci_core.c:1469 process_one_work kernel/workqueue.c:3257 [inline] process_scheduled_works+0xaec/0x17a0 kernel/workqueue.c:3340 worker_thread+0xda6/0x1360 kernel/workqueue.c:3421 kthread+0x726/0x8b0 kernel/kthread.c:463 ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: (detected by 1, t=10592 jiffies, g=14921, q=1448 ncpus=2) rcu: All QSes seen, last rcu_preempt kthread activity 91 (4294977071-4294976980), jiffies_till_next_fqs=1, root ->qsmask 0x0