============================================ WARNING: possible recursive locking detected 6.12.0-rc4-syzkaller-g2ed7316a506c #0 Not tainted -------------------------------------------- syz.2.84/6152 is trying to acquire lock: ffffc9000bf010d8 (&rb->spinlock){-.-.}-{2:2}, at: __bpf_ringbuf_reserve+0x1ea/0x600 kernel/bpf/ringbuf.c:427 but task is already holding lock: ffffc9000b8f70d8 (&rb->spinlock){-.-.}-{2:2}, at: __bpf_ringbuf_reserve+0x1ea/0x600 kernel/bpf/ringbuf.c:427 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 3 locks held by syz.2.84/6152: #0: ffffffff8e939de0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #0: ffffffff8e939de0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffffffff8e939de0 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2339 [inline] #0: ffffffff8e939de0 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run3+0x24c/0x5a0 kernel/trace/bpf_trace.c:2382 #1: ffffc9000b8f70d8 (&rb->spinlock){-.-.}-{2:2}, at: __bpf_ringbuf_reserve+0x1ea/0x600 kernel/bpf/ringbuf.c:427 #2: ffffffff8e939de0 (rcu_read_lock){....}-{1:2}, at: trace_call_bpf+0xbc/0x8a0 stack backtrace: CPU: 1 UID: 0 PID: 6152 Comm: syz.2.84 Not tainted 6.12.0-rc4-syzkaller-g2ed7316a506c #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_deadlock_bug+0x483/0x620 kernel/locking/lockdep.c:3037 check_deadlock kernel/locking/lockdep.c:3089 [inline] validate_chain+0x15e2/0x5920 kernel/locking/lockdep.c:3891 __lock_acquire+0x1384/0x2050 kernel/locking/lockdep.c:5202 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162 __bpf_ringbuf_reserve+0x1ea/0x600 kernel/bpf/ringbuf.c:427 ____bpf_ringbuf_output kernel/bpf/ringbuf.c:553 [inline] bpf_ringbuf_output+0x67/0x1e0 kernel/bpf/ringbuf.c:543 bpf_prog_4aaef4562453526c+0x43/0x47 bpf_dispatcher_nop_func include/linux/bpf.h:1290 [inline] __bpf_prog_run include/linux/filter.h:701 [inline] bpf_prog_run include/linux/filter.h:708 [inline] bpf_prog_run_array include/linux/bpf.h:2165 [inline] trace_call_bpf+0x369/0x8a0 kernel/trace/bpf_trace.c:146 perf_trace_run_bpf_submit+0x82/0x180 kernel/events/core.c:10416 perf_trace_lock_acquire+0x3c3/0x4f0 include/trace/events/lock.h:24 trace_lock_acquire include/trace/events/lock.h:24 [inline] lock_acquire+0x51b/0x550 kernel/locking/lockdep.c:5796 rcu_lock_acquire include/linux/rcupdate.h:337 [inline] rcu_read_lock include/linux/rcupdate.h:849 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2339 [inline] bpf_trace_run2+0x219/0x540 kernel/trace/bpf_trace.c:2381 trace_contention_end+0x114/0x140 include/trace/events/lock.h:122 __pv_queued_spin_lock_slowpath+0xb7e/0xdb0 kernel/locking/qspinlock.c:557 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:584 [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+0x272/0x370 kernel/locking/spinlock_debug.c:116 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline] _raw_spin_lock_irqsave+0xe1/0x120 kernel/locking/spinlock.c:162 __bpf_ringbuf_reserve+0x1ea/0x600 kernel/bpf/ringbuf.c:427 ____bpf_ringbuf_output kernel/bpf/ringbuf.c:553 [inline] bpf_ringbuf_output+0x67/0x1e0 kernel/bpf/ringbuf.c:543 bpf_prog_a3e2825f60354855+0x46/0x4a bpf_dispatcher_nop_func include/linux/bpf.h:1290 [inline] __bpf_prog_run include/linux/filter.h:701 [inline] bpf_prog_run include/linux/filter.h:708 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2340 [inline] bpf_trace_run3+0x33a/0x5a0 kernel/trace/bpf_trace.c:2382 trace_kmem_cache_free include/trace/events/kmem.h:114 [inline] kmem_cache_free+0x355/0x420 mm/slub.c:4680 kfree_skb_reason include/linux/skbuff.h:1262 [inline] __skb_queue_purge_reason include/linux/skbuff.h:3305 [inline] skb_queue_purge_reason+0x3c5/0x500 net/core/skbuff.c:3945 skb_queue_purge include/linux/skbuff.h:3318 [inline] packet_release+0xb15/0xcd0 net/packet/af_packet.c:3246 __sock_release net/socket.c:658 [inline] sock_release+0x82/0x150 net/socket.c:686 __sys_socketpair+0x6d1/0x720 __do_sys_socketpair net/socket.c:1832 [inline] __se_sys_socketpair net/socket.c:1829 [inline] __x64_sys_socketpair+0x9b/0xb0 net/socket.c:1829 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f9a1a17e719 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f9a1b013038 EFLAGS: 00000246 ORIG_RAX: 0000000000000035 RAX: ffffffffffffffda RBX: 00007f9a1a336058 RCX: 00007f9a1a17e719 RDX: 0000000000000300 RSI: 000000000000000a RDI: 0000000000000011 RBP: 00007f9a1a1f139e R08: 0000000000000000 R09: 0000000000000000 R10: 0000000020000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000001 R14: 00007f9a1a336058 R15: 00007ffe8da79078