============================================ WARNING: possible recursive locking detected 6.14.0-syzkaller-ga27a97f71394 #0 Not tainted -------------------------------------------- syz.7.5644/17733 is trying to acquire lock: ffffc900172db0d8 (&rb->spinlock){-.-.}-{2:2}, at: __bpf_ringbuf_reserve+0x20e/0x650 kernel/bpf/ringbuf.c:423 but task is already holding lock: ffffc900171ad0d8 (&rb->spinlock){-.-.}-{2:2}, at: __bpf_ringbuf_reserve+0x20e/0x650 kernel/bpf/ringbuf.c:423 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 4 locks held by syz.7.5644/17733: #0: ffff8880b8639b18 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:605 #1: ffffffff8ed3dfe0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #1: ffffffff8ed3dfe0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #1: ffffffff8ed3dfe0 (rcu_read_lock){....}-{1:3}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2362 [inline] #1: ffffffff8ed3dfe0 (rcu_read_lock){....}-{1:3}, at: bpf_trace_run2+0x1fe/0x550 kernel/trace/bpf_trace.c:2404 #2: ffffc900171ad0d8 (&rb->spinlock){-.-.}-{2:2}, at: __bpf_ringbuf_reserve+0x20e/0x650 kernel/bpf/ringbuf.c:423 #3: ffffffff8ed3dfe0 (rcu_read_lock){....}-{1:3}, at: trace_call_bpf+0xb9/0x8a0 kernel/trace/bpf_trace.c:-1 stack backtrace: CPU: 0 UID: 0 PID: 17733 Comm: syz.7.5644 Not tainted 6.14.0-syzkaller-ga27a97f71394 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_deadlock_bug+0x2be/0x2d0 kernel/locking/lockdep.c:3042 check_deadlock kernel/locking/lockdep.c:3094 [inline] validate_chain+0x928/0x24e0 kernel/locking/lockdep.c:3896 __lock_acquire+0xad5/0xd80 kernel/locking/lockdep.c:5235 lock_acquire+0x116/0x2f0 kernel/locking/lockdep.c:5866 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd8/0x130 kernel/locking/spinlock.c:162 __bpf_ringbuf_reserve+0x20e/0x650 kernel/bpf/ringbuf.c:423 ____bpf_ringbuf_reserve kernel/bpf/ringbuf.c:474 [inline] bpf_ringbuf_reserve+0x5c/0x70 kernel/bpf/ringbuf.c:466 bpf_prog_020e6543638c60de+0x36/0x53 bpf_dispatcher_nop_func include/linux/bpf.h:1316 [inline] __bpf_prog_run include/linux/filter.h:718 [inline] bpf_prog_run include/linux/filter.h:725 [inline] bpf_prog_run_array include/linux/bpf.h:2215 [inline] trace_call_bpf+0x36a/0x8a0 kernel/trace/bpf_trace.c:146 perf_trace_run_bpf_submit+0x82/0x180 kernel/events/core.c:10807 do_perf_trace_lock include/trace/events/lock.h:50 [inline] perf_trace_lock+0x39c/0x4a0 include/trace/events/lock.h:50 __do_trace_lock_release include/trace/events/lock.h:69 [inline] trace_lock_release include/trace/events/lock.h:69 [inline] lock_release+0x3b4/0x3e0 kernel/locking/lockdep.c:5877 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:149 [inline] _raw_spin_unlock_irqrestore+0x7a/0x140 kernel/locking/spinlock.c:194 __bpf_ringbuf_reserve+0x4f8/0x650 kernel/bpf/ringbuf.c:449 ____bpf_ringbuf_reserve kernel/bpf/ringbuf.c:474 [inline] bpf_ringbuf_reserve+0x5c/0x70 kernel/bpf/ringbuf.c:466 bpf_prog_76e427a82e237c93+0x36/0x62 bpf_dispatcher_nop_func include/linux/bpf.h:1316 [inline] __bpf_prog_run include/linux/filter.h:718 [inline] bpf_prog_run include/linux/filter.h:725 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2363 [inline] bpf_trace_run2+0x2ee/0x550 kernel/trace/bpf_trace.c:2404 __bpf_trace_tlb_flush+0x176/0x230 include/trace/events/tlb.h:38 __do_trace_tlb_flush include/trace/events/tlb.h:38 [inline] trace_tlb_flush+0x11c/0x140 include/trace/events/tlb.h:38 switch_mm_irqs_off+0x5da/0xb00 arch/x86/mm/tlb.c:-1 context_switch kernel/sched/core.c:5366 [inline] __schedule+0x13a1/0x5240 kernel/sched/core.c:6767 preempt_schedule_common+0x84/0xd0 kernel/sched/core.c:6947 preempt_schedule+0xe4/0xf0 kernel/sched/core.c:6971 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 class_preempt_destructor include/linux/preempt.h:481 [inline] try_to_wake_up+0xa93/0x15d0 kernel/sched/core.c:4335 wake_up_process kernel/sched/core.c:4461 [inline] wake_up_q+0xc8/0x120 kernel/sched/core.c:1080 futex_wake+0x525/0x5d0 kernel/futex/waitwake.c:199 do_futex+0x3d5/0x5a0 kernel/futex/syscalls.c:107 __do_sys_futex kernel/futex/syscalls.c:179 [inline] __se_sys_futex+0x436/0x4c0 kernel/futex/syscalls.c:160 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f93c038e169 Code: Unable to access opcode bytes at 0x7f93c038e13f. RSP: 002b:00007ffcd0558c48 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: ffffffffffffffda RBX: 00007f93c05b5fa8 RCX: 00007f93c038e169 RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007f93c05b5fa8 RBP: 0000000000000000 R08: 0000000000000001 R09: 00000004d0558f3f R10: 00007f93c05b5fa0 R11: 0000000000000246 R12: 00007f93c05b5fac R13: 00007f93c05b5fa0 R14: 00000000000007fa R15: 0000000000000003