============================================ WARNING: possible recursive locking detected 6.14.0-syzkaller-g8582d9ab3efd #0 Not tainted -------------------------------------------- syz.0.1/5948 is trying to acquire lock: ffffc900045390d8 (&rb->spinlock){-...}-{2:2}, at: __bpf_ringbuf_reserve+0x20e/0x650 kernel/bpf/ringbuf.c:423 but task is already holding lock: ffffc900052310d8 (&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 6 locks held by syz.0.1/5948: #0: ffff88803421dca8 (&ctx->mutex){+.+.}-{4:4}, at: perf_event_ctx_lock_nested+0x418/0x590 kernel/events/core.c:1357 #1: ffffffff8edaab68 (bpf_event_mutex){+.+.}-{4:4}, at: perf_event_attach_bpf_prog+0xe9/0x3c0 kernel/trace/bpf_trace.c:2211 #2: ffff8880b8739b18 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:605 #3: ffffffff8ed3dfe0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #3: ffffffff8ed3dfe0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #3: ffffffff8ed3dfe0 (rcu_read_lock){....}-{1:3}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2362 [inline] #3: ffffffff8ed3dfe0 (rcu_read_lock){....}-{1:3}, at: bpf_trace_run2+0x1fe/0x550 kernel/trace/bpf_trace.c:2404 #4: ffffc900052310d8 (&rb->spinlock){-...}-{2:2}, at: __bpf_ringbuf_reserve+0x20e/0x650 kernel/bpf/ringbuf.c:423 #5: ffffffff8ed3dfe0 (rcu_read_lock){....}-{1:3}, at: trace_call_bpf+0xb9/0x8a0 kernel/trace/bpf_trace.c:-1 stack backtrace: CPU: 1 UID: 0 PID: 5948 Comm: syz.0.1 Not tainted 6.14.0-syzkaller-g8582d9ab3efd #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_ba4789e7f2e155d6+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+0x4c5/0x650 kernel/bpf/ringbuf.c:461 ____bpf_ringbuf_reserve kernel/bpf/ringbuf.c:474 [inline] bpf_ringbuf_reserve+0x5c/0x70 kernel/bpf/ringbuf.c:466 bpf_prog_c6421efbcf8bbe39+0x3f/0xa8 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_notrace+0x103/0x140 kernel/sched/core.c:7040 preempt_schedule_notrace_thunk+0x16/0x30 arch/x86/entry/thunk.S:13 class_preempt_notrace_destructor include/linux/preempt.h:482 [inline] __do_trace_lock_release include/trace/events/lock.h:69 [inline] trace_lock_release include/trace/events/lock.h:69 [inline] lock_release+0x3cc/0x3e0 kernel/locking/lockdep.c:5877 __mutex_unlock_slowpath+0xee/0x800 kernel/locking/mutex.c:907 perf_event_attach_bpf_prog+0x2fa/0x3c0 kernel/trace/bpf_trace.c:2234 _perf_ioctl kernel/events/core.c:6317 [inline] perf_ioctl+0xa75/0x25d0 kernel/events/core.c:6377 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:892 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: 0033:0x7fcfebb8e169 Code: Unable to access opcode bytes at 0x7fcfebb8e13f. RSP: 002b:00007fcfe95d3038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fcfebdb6240 RCX: 00007fcfebb8e169 RDX: 000000000000000f RSI: 0000000040042408 RDI: 0000000000000003 RBP: 00007fcfebc10a68 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fcfebdb6240 R15: 00007fff1d6bf418