============================================ WARNING: possible recursive locking detected 6.1.131-syzkaller #0 Not tainted -------------------------------------------- kworker/u4:4/75 is trying to acquire lock: ffffc9000515d0d8 (&rb->spinlock){..-.}-{2:2}, at: __bpf_ringbuf_reserve+0x1e6/0x600 kernel/bpf/ringbuf.c:413 but task is already holding lock: ffffc900050f10d8 (&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 6 locks held by kworker/u4:4/75: #0: ffff888017c79138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x806/0x1260 kernel/workqueue.c:2267 #1: ffffc900020dfd20 ((reaper_work).work){+.+.}-{0:0}, at: process_one_work+0x806/0x1260 kernel/workqueue.c:2267 #2: ffff8880b8e3a9d8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:537 #3: ffffffff8d32e6c0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #3: ffffffff8d32e6c0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #3: ffffffff8d32e6c0 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2283 [inline] #3: ffffffff8d32e6c0 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run4+0x16a/0x470 kernel/trace/bpf_trace.c:2325 #4: ffffc900050f10d8 (&rb->spinlock){..-.}-{2:2}, at: __bpf_ringbuf_reserve+0x1e6/0x600 kernel/bpf/ringbuf.c:413 #5: ffffffff8d32e6c0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #5: ffffffff8d32e6c0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #5: ffffffff8d32e6c0 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2283 [inline] #5: ffffffff8d32e6c0 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0x110/0x410 kernel/trace/bpf_trace.c:2323 stack backtrace: CPU: 0 PID: 75 Comm: kworker/u4:4 Not tainted 6.1.131-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Workqueue: events_unbound fsnotify_mark_destroy_workfn 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_a3e2825f60354855+0x3d/0x41 bpf_dispatcher_nop_func include/linux/bpf.h:1000 [inline] __bpf_prog_run include/linux/filter.h:603 [inline] bpf_prog_run include/linux/filter.h:610 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2284 [inline] bpf_trace_run2+0x1fd/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_output kernel/bpf/ringbuf.c:539 [inline] bpf_ringbuf_output+0x63/0x1e0 kernel/bpf/ringbuf.c:529 bpf_prog_918f90024333f9ff+0x3a/0x3e bpf_dispatcher_nop_func include/linux/bpf.h:1000 [inline] __bpf_prog_run include/linux/filter.h:603 [inline] bpf_prog_run include/linux/filter.h:610 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2284 [inline] bpf_trace_run4+0x253/0x470 kernel/trace/bpf_trace.c:2325 __traceiter_sched_switch+0x91/0xc0 include/trace/events/sched.h:222 trace_sched_switch include/trace/events/sched.h:222 [inline] __schedule+0x2128/0x4570 kernel/sched/core.c:6557 schedule+0xbf/0x180 kernel/sched/core.c:6636 schedule_timeout+0xac/0x300 kernel/time/timer.c:1941 do_wait_for_common kernel/sched/completion.c:85 [inline] __wait_for_common kernel/sched/completion.c:106 [inline] wait_for_common kernel/sched/completion.c:117 [inline] wait_for_completion+0x350/0x610 kernel/sched/completion.c:138 __synchronize_srcu+0x2b7/0x360 kernel/rcu/srcutree.c:1243 fsnotify_mark_destroy_workfn+0x142/0x340 fs/notify/mark.c:924 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