syzbot

watchdog: BUG: soft lockup - CPU#0 stuck for 23s! [kworker/0:4:6633]
Modules linked in:
irq event stamp: 190839
hardirqs last  enabled at (190838): [<ffff80008af960cc>] irqentry_exit+0x1b4/0x2f4 kernel/entry/common.c:219
hardirqs last disabled at (190839): [<ffff80008af941ac>] enter_from_kernel_mode+0x14/0x34 arch/arm64/kernel/entry-common.c:42
softirqs last  enabled at (184066): [<ffff8000899305ac>] local_bh_enable+0x10/0x34 include/linux/bottom_half.h:32
softirqs last disabled at (184088): [<ffff8000893f2ca8>] local_bh_disable+0x10/0x34 include/linux/bottom_half.h:19
CPU: 0 UID: 0 PID: 6633 Comm: kworker/0:4 Tainted: G             L      syzkaller #0 PREEMPT 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/03/2025
Workqueue: events ser_release
pstate: 03400005 (nzcv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=--)
pc : queued_spin_lock_slowpath+0x138/0xae8 kernel/locking/qspinlock.c:197
lr : queued_spin_lock_slowpath+0x144/0xae8 kernel/locking/qspinlock.c:197
sp : ffff8000a4af7460
x29: ffff8000a4af7500 x28: 1fffe0001a93dda9 x27: 1fffe00018d41722
x26: ffff0000c6a0b900 x25: dfff800000000000 x24: ffff70001495ee90
x23: 0000000000000001 x22: ffff0000c6a0b910 x21: ffff0000d49eed48
x20: ffff0000d49eed50 x19: ffff0000d49eed40 x18: 00000000ffffffff
x17: ffff800093598000 x16: ffff80008054435c x15: 0000000000000001
x14: 1fffe0001a93dda8 x13: 0000000000000000 x12: 0000000000000000
x11: ffff60001a93dda9 x10: dfff800000000000 x9 : 0000000000000000
x8 : 0000000000000001 x7 : ffff8000893e7794 x6 : 0000000000000000
x5 : 0000000000000020 x4 : ffff8000a4af7420 x3 : ffff80008afb9c10
x2 : 0000000000000000 x1 : 0000000000000001 x0 : 0000000000000001
Call trace:
 __cmpwait_case_8 arch/arm64/include/asm/cmpxchg.h:229 [inline] (P)
 __cmpwait arch/arm64/include/asm/cmpxchg.h:257 [inline] (P)
 queued_spin_lock_slowpath+0x138/0xae8 kernel/locking/qspinlock.c:197 (P)
 queued_spin_lock include/asm-generic/qspinlock.h:114 [inline]
 do_raw_spin_lock+0x2a8/0x2cc kernel/locking/spinlock_debug.c:116
 __raw_spin_lock include/linux/spinlock_api_smp.h:134 [inline]
 _raw_spin_lock+0x50/0x60 kernel/locking/spinlock.c:154
 spin_lock include/linux/spinlock.h:351 [inline]
 __netif_tx_lock include/linux/netdevice.h:4710 [inline]
 netif_freeze_queues net/sched/sch_generic.c:464 [inline]
 netif_tx_lock+0x9c/0x1d8 net/sched/sch_generic.c:473
 netif_tx_lock_bh include/linux/netdevice.h:4795 [inline]
 netdev_watchdog_down net/sched/sch_generic.c:573 [inline]
 dev_deactivate_many+0x274/0xac0 net/sched/sch_generic.c:1366
 __dev_close_many+0x220/0x704 net/core/dev.c:1740
 netif_close_many+0x1e8/0x448 net/core/dev.c:1781
 netif_close+0x148/0x1f8 net/core/dev.c:1798
 dev_close+0xf8/0x1e4 net/core/dev_api.c:220
 ser_release+0x150/0x1ec drivers/net/caif/caif_serial.c:295
 process_one_work+0x7c0/0x1558 kernel/workqueue.c:3257
 process_scheduled_works kernel/workqueue.c:3340 [inline]
 worker_thread+0x958/0xed8 kernel/workqueue.c:3421
 kthread+0x5fc/0x75c kernel/kthread.c:463
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:844
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 2469 Comm: aoe_tx0 Tainted: G             L      syzkaller #0 PREEMPT 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/03/2025
pstate: 83400005 (Nzcv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=--)
pc : __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
pc : _raw_spin_unlock_irqrestore+0x44/0x98 kernel/locking/spinlock.c:194
lr : __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline]
lr : _raw_spin_unlock_irqrestore+0x38/0x98 kernel/locking/spinlock.c:194
sp : ffff8000a20a7700
x29: ffff8000a20a7700 x28: ffff0000f118a1b0 x27: 0000000000000000
x26: ffff0000f118a140 x25: ffff0000c9be0238 x24: dfff800000000000
x23: 0000000000000003 x22: 0000000000000000 x21: ffff8000914d0160
x20: ffff80009794c8e0 x19: 0000000000000000 x18: 00000000ffffffff
x17: ffff800093598000 x16: ffff80008053826c x15: 0000000000000001
x14: 1ffff00012f2991c x13: 0000000000000000 x12: 0000000000000000
x11: ffff800093397d48 x10: 0000000000000003 x9 : 0000000000000000
x8 : 00000000000000c0 x7 : ffff800083bc188c x6 : 0000000000000000
x5 : 0000000000000001 x4 : 0000000000000001 x3 : 0000000000000010
x2 : 0000000000000002 x1 : ffff80008ee5b741 x0 : ffff80010c451000
Call trace:
 __daif_local_irq_restore arch/arm64/include/asm/irqflags.h:175 [inline] (P)
 arch_local_irq_restore arch/arm64/include/asm/irqflags.h:195 [inline] (P)
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline] (P)
 _raw_spin_unlock_irqrestore+0x44/0x98 kernel/locking/spinlock.c:194 (P)
 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
 uart_port_unlock_irqrestore include/linux/serial_core.h:788 [inline]
 uart_port_unlock_deref+0x108/0x2ec drivers/tty/serial/serial_core.c:91
 uart_write_room+0xa4/0x15c drivers/tty/serial/serial_core.c:647
 tty_write_room+0x6c/0x8c drivers/tty/tty_ioctl.c:69
 handle_tx+0x128/0x5fc drivers/net/caif/caif_serial.c:212
 caif_xmit+0x108/0x150 drivers/net/caif/caif_serial.c:268
 __netdev_start_xmit include/linux/netdevice.h:5273 [inline]
 netdev_start_xmit include/linux/netdevice.h:5282 [inline]
 xmit_one net/core/dev.c:3853 [inline]
 dev_hard_start_xmit+0x298/0x890 net/core/dev.c:3869
 __dev_queue_xmit+0x10c4/0x2a68 net/core/dev.c:4817
 dev_queue_xmit include/linux/netdevice.h:3381 [inline]
 tx+0x9c/0x1cc drivers/block/aoe/aoenet.c:62
 kthread+0x164/0x354 drivers/block/aoe/aoecmd.c:1241
 kthread+0x5fc/0x75c kernel/kthread.c:463
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:844