syzbot

watchdog: BUG: soft lockup - CPU#0 stuck for 23s! [kworker/0:0:8]
Modules linked in:
irq event stamp: 48533
hardirqs last  enabled at (48532): [<ffff80008b545ee4>] __exit_to_kernel_mode arch/arm64/kernel/entry-common.c:85 [inline]
hardirqs last  enabled at (48532): [<ffff80008b545ee4>] exit_to_kernel_mode+0xdc/0x10c arch/arm64/kernel/entry-common.c:95
hardirqs last disabled at (48533): [<ffff80008b54395c>] __el1_irq arch/arm64/kernel/entry-common.c:557 [inline]
hardirqs last disabled at (48533): [<ffff80008b54395c>] el1_interrupt+0x24/0x68 arch/arm64/kernel/entry-common.c:575
softirqs last  enabled at (41020): [<ffff8000860049d0>] pppoe_flush_dev drivers/net/ppp/pppoe.c:327 [inline]
softirqs last  enabled at (41020): [<ffff8000860049d0>] pppoe_device_event+0x464/0x4a0 drivers/net/ppp/pppoe.c:346
softirqs last disabled at (41024): [<ffff80008987a614>] local_bh_disable+0x10/0x34 include/linux/bottom_half.h:19
CPU: 0 UID: 0 PID: 8 Comm: kworker/0:0 Not tainted 6.12.0-syzkaller-g7b1d1d4cfac0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Workqueue: events ser_release
pstate: 00400005 (nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : queued_spin_lock_slowpath+0x15c/0xd00 kernel/locking/qspinlock.c:380
lr : queued_spin_lock_slowpath+0x168/0xd00 kernel/locking/qspinlock.c:380
sp : ffff800097977520
x29: ffff8000979775c0 x28: 1fffe0001ad2c420 x27: 1ffff00012f2eeb0
x26: dfff800000000000 x25: 1fffe0001833ab5a x24: ffff800097977540
x23: ffff800097977580 x22: ffff700012f2eea8 x21: 0000000000000001
x20: 0000000000000001 x19: ffff0000d6962100 x18: ffff800097977400
x17: 000000000002b14e x16: ffff800080aca118 x15: 0000000000000001
x14: 1fffe0001ad2c420 x13: 0000000000000000 x12: 0000000000000000
x11: ffff60001ad2c421 x10: 1fffe0001ad2c420 x9 : 0000000000000000
x8 : 0000000000000001 x7 : 0000000000000000 x6 : 0000000000000000
x5 : ffff800093604598 x4 : 0000000000000008 x3 : ffff80008b63a244
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+0x15c/0xd00 kernel/locking/qspinlock.c:380 (P)
 queued_spin_lock_slowpath+0x168/0xd00 kernel/locking/qspinlock.c:380 (L)
 queued_spin_lock include/asm-generic/qspinlock.h:114 [inline]
 do_raw_spin_lock+0x2ec/0x334 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:4371 [inline]
 netif_freeze_queues net/sched/sch_generic.c:460 [inline]
 netif_tx_lock+0x9c/0x1d8 net/sched/sch_generic.c:469
 netif_tx_lock_bh include/linux/netdevice.h:4455 [inline]
 dev_watchdog_down net/sched/sch_generic.c:574 [inline]
 dev_deactivate_many+0x274/0xa8c net/sched/sch_generic.c:1369
 __dev_close_many+0x270/0x3c8 net/core/dev.c:1547
 dev_close_many+0x1e0/0x474 net/core/dev.c:1585
 dev_close+0x174/0x250 net/core/dev.c:1611
 ser_release+0x188/0x238 drivers/net/caif/caif_serial.c:309
 process_one_work+0x7bc/0x1600 kernel/workqueue.c:3229
 process_scheduled_works kernel/workqueue.c:3310 [inline]
 worker_thread+0x97c/0xeec kernel/workqueue.c:3391
 kthread+0x288/0x310 kernel/kthread.c:389
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:862
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 2346 Comm: aoe_tx0 Not tainted 6.12.0-syzkaller-g7b1d1d4cfac0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
pstate: 80400005 (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 : ffff8000a1ac7730
x29: ffff8000a1ac7730 x28: ffff0000cdc8b0b0 x27: dfff800000000000
x26: 0000000000000000 x25: ffff800091292c00 x24: ffff0000c9228f48
x23: 0000000000000003 x22: 0000000000000000 x21: ffff800091292c00
x20: ffff80009776cde0 x19: 0000000000000000 x18: ffff8000a1ac73e0
x17: 000000000002b0e8 x16: ffff800080355c58 x15: 0000000000000001
x14: 1ffff00012eed9bc x13: ffff8000a1ac8000 x12: 0000000000000003
x11: 0000000000000202 x10: 0000000000000003 x9 : 0000000000000000
x8 : 00000000000000c0 x7 : ffff800083ec1ff0 x6 : 0000000000000000
x5 : 0000000000000001 x4 : 0000000000000001 x3 : 0000000000000000
x2 : 0000000000000002 x1 : ffff80008b6c4000 x0 : ffff800123e21000
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)
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline] (L)
 _raw_spin_unlock_irqrestore+0x38/0x98 kernel/locking/spinlock.c:194 (L)
 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
 uart_port_unlock_irqrestore include/linux/serial_core.h:782 [inline]
 uart_write+0x4b0/0x9b4 drivers/tty/serial/serial_core.c:628
 handle_tx+0x200/0x604 drivers/net/caif/caif_serial.c:236
 caif_xmit+0x108/0x150 drivers/net/caif/caif_serial.c:282
 __netdev_start_xmit include/linux/netdevice.h:4928 [inline]
 netdev_start_xmit include/linux/netdevice.h:4937 [inline]
 xmit_one net/core/dev.c:3588 [inline]
 dev_hard_start_xmit+0x260/0x904 net/core/dev.c:3604
 __dev_queue_xmit+0x1638/0x3548 net/core/dev.c:4432
 dev_queue_xmit include/linux/netdevice.h:3094 [inline]
 tx+0x9c/0x1cc drivers/block/aoe/aoenet.c:62
 kthread+0x1ac/0x374 drivers/block/aoe/aoecmd.c:1237
 kthread+0x288/0x310 kernel/kthread.c:389
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:862