============================================ WARNING: possible recursive locking detected 6.0.0-rc1-syzkaller-00160-g4c2d0b039c5c #0 Not tainted -------------------------------------------- kworker/0:2/26458 is trying to acquire lock: ffffffff8cd7d238 (trace_printk_lock){....}-{2:2}, at: ____bpf_trace_printk kernel/trace/bpf_trace.c:388 [inline] ffffffff8cd7d238 (trace_printk_lock){....}-{2:2}, at: bpf_trace_printk+0x151/0x200 kernel/trace/bpf_trace.c:374 but task is already holding lock: ffffffff8cd7d238 (trace_printk_lock){....}-{2:2}, at: ____bpf_trace_printk kernel/trace/bpf_trace.c:388 [inline] ffffffff8cd7d238 (trace_printk_lock){....}-{2:2}, at: bpf_trace_printk+0x151/0x200 kernel/trace/bpf_trace.c:374 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(trace_printk_lock); lock(trace_printk_lock); *** DEADLOCK *** May be due to missing lock nesting notation 6 locks held by kworker/0:2/26458: #0: ffff888012064d38 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x796/0xd10 kernel/workqueue.c:2262 #1: ffffc90007a2fd00 ((work_completion)(&(&hwstats->traffic_dw)->work)){+.+.}-{0:0}, at: process_one_work+0x7d0/0xd10 kernel/workqueue.c:2264 #2: ffff88803b16a510 (&hwstats->hwsdev_list_lock){+.+.}-{3:3}, at: nsim_dev_hwstats_traffic_work+0x2f/0x1c0 drivers/net/netdevsim/hwstats.c:47 #3: ffffffff8cd207a0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:279 #4: ffffffff8cd7d238 (trace_printk_lock){....}-{2:2}, at: ____bpf_trace_printk kernel/trace/bpf_trace.c:388 [inline] #4: ffffffff8cd7d238 (trace_printk_lock){....}-{2:2}, at: bpf_trace_printk+0x151/0x200 kernel/trace/bpf_trace.c:374 #5: ffffffff8cd207a0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:279 stack backtrace: CPU: 0 PID: 26458 Comm: kworker/0:2 Not tainted 6.0.0-rc1-syzkaller-00160-g4c2d0b039c5c #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022 Workqueue: events nsim_dev_hwstats_traffic_work Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106 print_deadlock_bug kernel/locking/lockdep.c:2988 [inline] check_deadlock kernel/locking/lockdep.c:3031 [inline] validate_chain+0x4897/0x6600 kernel/locking/lockdep.c:3816 __lock_acquire+0x1292/0x1f60 kernel/locking/lockdep.c:5053 lock_acquire+0x1a7/0x400 kernel/locking/lockdep.c:5666 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162 ____bpf_trace_printk kernel/trace/bpf_trace.c:388 [inline] bpf_trace_printk+0x151/0x200 kernel/trace/bpf_trace.c:374 bpf_prog_0605f9f479290f07+0x2f/0x33 bpf_dispatcher_nop_func include/linux/bpf.h:903 [inline] __bpf_prog_run include/linux/filter.h:594 [inline] bpf_prog_run include/linux/filter.h:601 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2046 [inline] bpf_trace_run2+0x18a/0x320 kernel/trace/bpf_trace.c:2083 trace_contention_begin+0x16b/0x190 include/trace/events/lock.h:95 __pv_queued_spin_lock_slowpath+0x10f/0xc60 kernel/locking/qspinlock.c:405 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:591 [inline] queued_spin_lock_slowpath+0x42/0x50 arch/x86/include/asm/qspinlock.h:51 queued_spin_lock include/asm-generic/qspinlock.h:114 [inline] do_raw_spin_lock+0x264/0x360 kernel/locking/spinlock_debug.c:115 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline] _raw_spin_lock_irqsave+0xdd/0x120 kernel/locking/spinlock.c:162 ____bpf_trace_printk kernel/trace/bpf_trace.c:388 [inline] bpf_trace_printk+0x151/0x200 kernel/trace/bpf_trace.c:374 bpf_prog_0605f9f479290f07+0x2f/0x33 bpf_dispatcher_nop_func include/linux/bpf.h:903 [inline] __bpf_prog_run include/linux/filter.h:594 [inline] bpf_prog_run include/linux/filter.h:601 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2046 [inline] bpf_trace_run2+0x18a/0x320 kernel/trace/bpf_trace.c:2083 trace_contention_begin+0x122/0x140 include/trace/events/lock.h:95 __mutex_lock_common+0x1ef/0x26c0 kernel/locking/mutex.c:605 __mutex_lock kernel/locking/mutex.c:747 [inline] mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:799 nsim_dev_hwstats_traffic_work+0x2f/0x1c0 drivers/net/netdevsim/hwstats.c:47 process_one_work+0x81c/0xd10 kernel/workqueue.c:2289 worker_thread+0xb14/0x1330 kernel/workqueue.c:2436 kthread+0x266/0x300 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 usb 2-1: USB disconnect, device number 90 sierra ttyUSB0: Sierra USB modem converter now disconnected from ttyUSB0 sierra 2-1:0.0: device disconnected usb 3-1: USB disconnect, device number 4 sierra ttyUSB0: Sierra USB modem converter now disconnected from ttyUSB0 sierra ttyUSB1: Sierra USB modem converter now disconnected from ttyUSB1 sierra 3-1:0.241: device disconnected