watchdog: BUG: soft lockup - CPU#1 stuck for 143s! [syz.2.796:9132] Modules linked in: irq event stamp: 14534849 hardirqs last enabled at (14534848): [] irqentry_exit+0x59e/0x620 kernel/entry/common.c:242 hardirqs last disabled at (14534849): [] sysvec_apic_timer_interrupt+0xe/0xc0 arch/x86/kernel/apic/apic.c:1056 softirqs last enabled at (13727104): [] __do_softirq kernel/softirq.c:656 [inline] softirqs last enabled at (13727104): [] invoke_softirq kernel/softirq.c:496 [inline] softirqs last enabled at (13727104): [] __irq_exit_rcu+0x5f/0x150 kernel/softirq.c:723 softirqs last disabled at (13727107): [] __do_softirq kernel/softirq.c:656 [inline] softirqs last disabled at (13727107): [] invoke_softirq kernel/softirq.c:496 [inline] softirqs last disabled at (13727107): [] __irq_exit_rcu+0x5f/0x150 kernel/softirq.c:723 CPU: 1 UID: 0 PID: 9132 Comm: syz.2.796 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 RIP: 0010:preempt_count kernel/rcu/tree_plugin.h:726 [inline] RIP: 0010:rcu_read_unlock_special+0x1/0x480 kernel/rcu/tree_plugin.h:730 Code: 4c 89 f7 e8 61 94 84 00 4c 89 ef e9 7a ff ff ff 66 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 <41> 57 41 56 41 55 41 54 53 48 83 ec 10 65 8b 2d 0b d4 70 11 f7 c5 RSP: 0018:ffffc90000a08878 EFLAGS: 00000206 RAX: 0000000000000000 RBX: ffff88806f226044 RCX: 0000000000000101 RDX: 0000000000000002 RSI: ffffffff8e169c78 RDI: ffff88806f225b80 RBP: dffffc0000000000 R08: ffffc90000a08d00 R09: 0000000000000000 R10: ffffc90000a089d8 R11: fffff5200014113d R12: 1ffff1100de44c08 R13: ffffc90000a01000 R14: ffff88806f226048 R15: dffffc0000000000 FS: 00007f7ab15eb6c0(0000) GS:ffff88812555c000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000020000000f000 CR3: 000000007feb0000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: __rcu_read_unlock+0x83/0xe0 kernel/rcu/tree_plugin.h:438 rcu_read_unlock include/linux/rcupdate.h:883 [inline] class_rcu_destructor include/linux/rcupdate.h:1193 [inline] unwind_next_frame+0x1aaf/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:2685 [inline] slab_free mm/slub.c:6165 [inline] kfree+0x1c1/0x630 mm/slub.c:6483 slab_free_after_rcu_debug+0x5e/0x220 mm/slub.c:6217 rcu_do_batch kernel/rcu/tree.c:2617 [inline] rcu_core+0x7cd/0x1070 kernel/rcu/tree.c:2869 handle_softirqs+0x22a/0x870 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:lock_acquire+0x20b/0x2e0 kernel/locking/lockdep.c:5872 Code: e9 30 ff ff ff e8 45 45 0d 0a f7 c3 00 02 00 00 0f 84 38 ff ff ff 65 48 8b 05 c1 b2 7a 11 48 3b 44 24 30 75 33 fb 48 83 c4 38 <5b> 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc 48 8d 3d fe 79 73 RSP: 0018:ffffc90002e9f7b8 EFLAGS: 00000286 RAX: faab4c28fde50700 RBX: 0000000000000246 RCX: 0000000080000001 RDX: 0000000066675a99 RSI: ffffffff8e169c78 RDI: ffffffff8c27c800 RBP: 0000000000000001 R08: ffffffff8224042e R09: ffff8880b87431d0 R10: ffffc90002e9f408 R11: fffff520005d3e83 R12: 0000000000000000 R13: ffff8880b87431d0 R14: 0000000000000000 R15: 0000000000000001 local_trylock_acquire include/linux/local_lock_internal.h:53 [inline] alloc_from_pcs mm/slub.c:4711 [inline] slab_alloc_node mm/slub.c:4851 [inline] kmem_cache_alloc_node_noprof+0x25a/0x690 mm/slub.c:4918 kmalloc_reserve net/core/skbuff.c:613 [inline] __alloc_skb+0x27d/0x7d0 net/core/skbuff.c:713 netlink_sendmsg+0x5d4/0xb40 net/netlink/af_netlink.c:1869 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0x972/0x9f0 net/socket.c:2592 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2646 __sys_sendmsg net/socket.c:2678 [inline] __do_sys_sendmsg net/socket.c:2683 [inline] __se_sys_sendmsg net/socket.c:2681 [inline] __x64_sys_sendmsg+0x1bd/0x2a0 net/socket.c:2681 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f7ab079c799 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:00007f7ab15eb028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f7ab0a16090 RCX: 00007f7ab079c799 RDX: 0000000000000000 RSI: 0000200000000180 RDI: 000000000000000e RBP: 00007f7ab0832c99 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f7ab0a16128 R14: 00007f7ab0a16090 R15: 00007ffcf9d2f398 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 5827 Comm: kworker/u9:3 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 Workqueue: hci5 hci_cmd_timeout RIP: 0010:univ8250_console_write+0x0/0xa0 drivers/tty/serial/8250/8250_core.c:395 Code: ff 4c 89 f7 e8 f1 3a f0 fc e9 ad fc ff ff 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 41 57 41 56 53 89 d3 49 89 f6 49 89 ff e8 ca dc 85 fc RSP: 0000:ffffc9000425f5f8 EFLAGS: 00000046 RAX: 1ffffffff1e0169a RBX: 0000000000000200 RCX: 0000000080000001 RDX: 0000000000000031 RSI: ffffffff9a2baa40 RDI: ffffffff8f00b4c0 RBP: ffffc9000425f710 R08: ffffffff81a4aad3 R09: ffffffff8e750b40 R10: dffffc0000000000 R11: ffffffff853fc550 R12: dffffc0000000000 R13: 0000000000000001 R14: ffffffff81a4aad3 R15: ffffffff8f00b4c0 FS: 0000000000000000(0000) GS:ffff88812545c000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fd54e886078 CR3: 000000007feb0000 CR4: 00000000003526f0 DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000200000000300 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: console_emit_next_record kernel/printk/printk.c:3183 [inline] console_flush_one_record kernel/printk/printk.c:3269 [inline] console_flush_all+0x718/0xb20 kernel/printk/printk.c:3343 __console_flush_and_unlock kernel/printk/printk.c:3373 [inline] console_unlock+0xd1/0x1c0 kernel/printk/printk.c:3413 vprintk_emit+0x485/0x560 kernel/printk/printk.c:2479 _printk+0xdd/0x130 kernel/printk/printk.c:2504 bt_err+0x121/0x180 net/bluetooth/lib.c:296 hci_cmd_timeout+0xff/0x1e0 net/bluetooth/hci_core.c:1474 process_one_work kernel/workqueue.c:3276 [inline] process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245