watchdog: BUG: soft lockup - CPU#0 stuck for 26s! [kworker/0:2:20588] Modules linked in: irq event stamp: 1068677 hardirqs last enabled at (1068676): [] __exit_to_kernel_mode arch/arm64/kernel/entry-common.c:84 [inline] hardirqs last enabled at (1068676): [] exit_to_kernel_mode+0xdc/0x10c arch/arm64/kernel/entry-common.c:94 hardirqs last disabled at (1068677): [] __el1_irq arch/arm64/kernel/entry-common.c:470 [inline] hardirqs last disabled at (1068677): [] el1_interrupt+0x24/0x68 arch/arm64/kernel/entry-common.c:488 softirqs last enabled at (1063232): [] pppoe_flush_dev drivers/net/ppp/pppoe.c:327 [inline] softirqs last enabled at (1063232): [] pppoe_device_event+0x45c/0x498 drivers/net/ppp/pppoe.c:346 softirqs last disabled at (1063234): [] local_bh_disable+0x10/0x34 include/linux/bottom_half.h:19 CPU: 0 PID: 20588 Comm: kworker/0:2 Not tainted 6.4.0-rc5-syzkaller-g45010c64f1e4 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/25/2023 Workqueue: events ser_release pstate: 00400005 (nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : queued_spin_lock_slowpath+0x15c/0xcf8 kernel/locking/qspinlock.c:383 lr : queued_spin_lock_slowpath+0x168/0xcf8 kernel/locking/qspinlock.c:383 sp : ffff8000a4e07560 x29: ffff8000a4e07600 x28: 1fffe00019f70f18 x27: 1ffff000149c0eb8 x26: dfff800000000000 x25: 1fffe00019f70f1a x24: ffff8000a4e07580 x23: ffff8000a4e075c0 x22: ffff7000149c0eb0 x21: 0000000000000001 x20: 0000000000000001 x19: ffff0000cfb878c0 x18: 000000006d3937a8 x17: 000000006bcd35a8 x16: ffff800080997a00 x15: 0000000000000000 x14: 1ffff00011bd80ac x13: dfff800000000000 x12: 0000000000000001 x11: 1fffe00019f70f18 x10: 0000000000000000 x9 : 0000000000000000 x8 : 0000000000000001 x7 : ffff80008883b014 x6 : 0000000000000000 x5 : 0000000000000000 x4 : 0000000000000001 x3 : ffff80008a522638 x2 : 0000000000000000 x1 : 0000000000000001 x0 : 0000000000000001 Call trace: __cmpwait_case_8 arch/arm64/include/asm/cmpxchg.h:249 [inline] __cmpwait arch/arm64/include/asm/cmpxchg.h:277 [inline] queued_spin_lock_slowpath+0x15c/0xcf8 kernel/locking/qspinlock.c:383 queued_spin_lock include/asm-generic/qspinlock.h:114 [inline] do_raw_spin_lock+0x320/0x348 kernel/locking/spinlock_debug.c:115 __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:350 [inline] __netif_tx_lock include/linux/netdevice.h:4366 [inline] netif_freeze_queues net/sched/sch_generic.c:459 [inline] netif_tx_lock+0x9c/0x1d8 net/sched/sch_generic.c:468 netif_tx_lock_bh include/linux/netdevice.h:4450 [inline] dev_watchdog_down net/sched/sch_generic.c:563 [inline] dev_deactivate_many+0x274/0x9fc net/sched/sch_generic.c:1340 __dev_close_many+0x26c/0x3c4 net/core/dev.c:1486 dev_close_many+0x1e0/0x470 net/core/dev.c:1524 dev_close+0x174/0x250 net/core/dev.c:1550 ser_release+0x188/0x238 drivers/net/caif/caif_serial.c:309 process_one_work+0x788/0x12d4 kernel/workqueue.c:2405 worker_thread+0x8e0/0xfe8 kernel/workqueue.c:2552 kthread+0x288/0x310 kernel/kthread.c:379 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:853