============================================ WARNING: possible recursive locking detected 6.1.128-syzkaller #0 Not tainted -------------------------------------------- kworker/u4:10/4485 is trying to acquire lock: ffffc900059150d8 (&rb->spinlock){-.-.}-{2:2}, at: __bpf_ringbuf_reserve+0x1e6/0x600 kernel/bpf/ringbuf.c:413 but task is already holding lock: ffffc90005ee90d8 (&rb->spinlock){-.-.}-{2:2}, at: __bpf_ringbuf_reserve+0x1e6/0x600 kernel/bpf/ringbuf.c:413 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&rb->spinlock); lock(&rb->spinlock); *** DEADLOCK *** May be due to missing lock nesting notation 7 locks held by kworker/u4:10/4485: #0: ffff888017c79138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x806/0x1260 kernel/workqueue.c:2267 #1: ffffc90004d3fd20 ((work_completion)(&(&nsim_dev->trap_data->trap_report_dw)->work)){+.+.}-{0:0}, at: process_one_work+0x806/0x1260 kernel/workqueue.c:2267 #2: ffff8880770212f8 (&devlink->lock_key#9){+.+.}-{3:3}, at: nsim_dev_trap_report_work+0x53/0xab0 drivers/net/netdevsim/dev.c:838 #3: ffff888059e9b0e0 (&nsim_trap_data->trap_lock){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] #3: ffff888059e9b0e0 (&nsim_trap_data->trap_lock){+.+.}-{2:2}, at: nsim_dev_trap_report drivers/net/netdevsim/dev.c:791 [inline] #3: ffff888059e9b0e0 (&nsim_trap_data->trap_lock){+.+.}-{2:2}, at: nsim_dev_trap_report_work+0x18d/0xab0 drivers/net/netdevsim/dev.c:851 #4: ffffffff8d32e680 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #4: ffffffff8d32e680 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #4: ffffffff8d32e680 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2283 [inline] #4: ffffffff8d32e680 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run3+0x146/0x440 kernel/trace/bpf_trace.c:2324 #5: ffffc90005ee90d8 (&rb->spinlock){-.-.}-{2:2}, at: __bpf_ringbuf_reserve+0x1e6/0x600 kernel/bpf/ringbuf.c:413 #6: ffffffff8d32e680 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #6: ffffffff8d32e680 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #6: ffffffff8d32e680 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2283 [inline] #6: ffffffff8d32e680 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0x110/0x410 kernel/trace/bpf_trace.c:2323 stack backtrace: CPU: 0 PID: 4485 Comm: kworker/u4:10 Not tainted 6.1.128-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 Workqueue: events_unbound nsim_dev_trap_report_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:2983 [inline] check_deadlock kernel/locking/lockdep.c:3026 [inline] validate_chain+0x4711/0x5950 kernel/locking/lockdep.c:3812 __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049 lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162 __bpf_ringbuf_reserve+0x1e6/0x600 kernel/bpf/ringbuf.c:413 ____bpf_ringbuf_output kernel/bpf/ringbuf.c:539 [inline] bpf_ringbuf_output+0x63/0x1e0 kernel/bpf/ringbuf.c:529 bpf_prog_044b88d9c832e6f0+0x45/0x49 bpf_dispatcher_nop_func include/linux/bpf.h:1000 [inline] __bpf_prog_run include/linux/filter.h:596 [inline] bpf_prog_run include/linux/filter.h:610 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2284 [inline] bpf_trace_run2+0x361/0x410 kernel/trace/bpf_trace.c:2323 trace_contention_end+0x14c/0x190 include/trace/events/lock.h:122 __pv_queued_spin_lock_slowpath+0x935/0xc50 kernel/locking/qspinlock.c:560 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+0x269/0x370 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_ringbuf_reserve+0x1e6/0x600 kernel/bpf/ringbuf.c:413 ____bpf_ringbuf_reserve kernel/bpf/ringbuf.c:464 [inline] bpf_ringbuf_reserve+0x58/0x70 kernel/bpf/ringbuf.c:456 bpf_prog_fe0ed97373b08409+0x25/0x42 bpf_dispatcher_nop_func include/linux/bpf.h:1000 [inline] __bpf_prog_run include/linux/filter.h:596 [inline] bpf_prog_run include/linux/filter.h:610 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2284 [inline] bpf_trace_run3+0x3a1/0x440 kernel/trace/bpf_trace.c:2324 __bpf_trace_kmem_cache_free+0x99/0xc0 include/trace/events/kmem.h:114 trace_kmem_cache_free include/trace/events/kmem.h:114 [inline] kmem_cache_free+0x418/0x510 mm/slub.c:3682 nsim_dev_trap_report drivers/net/netdevsim/dev.c:821 [inline] nsim_dev_trap_report_work+0x75d/0xab0 drivers/net/netdevsim/dev.c:851 process_one_work+0x917/0x1260 kernel/workqueue.c:2292 worker_thread+0xa47/0x1200 kernel/workqueue.c:2439 kthread+0x28d/0x320 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295