============================================ WARNING: possible recursive locking detected 6.1.131-syzkaller #0 Not tainted -------------------------------------------- syz.7.1321/8664 is trying to acquire lock: ffff888077a16218 (&qs->lock){-.-.}-{2:2}, at: __queue_map_get+0x146/0x4b0 kernel/bpf/queue_stack_maps.c:109 but task is already holding lock: ffff888054098218 (&qs->lock){-.-.}-{2:2}, at: __queue_map_get+0x146/0x4b0 kernel/bpf/queue_stack_maps.c:109 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&qs->lock); lock(&qs->lock); *** DEADLOCK *** May be due to missing lock nesting notation 5 locks held by syz.7.1321/8664: #0: ffffffff8d32e6c0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #0: ffffffff8d32e6c0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #0: ffffffff8d32e6c0 (rcu_read_lock){....}-{1:2}, at: bpf_test_timer_enter+0x19/0x140 net/bpf/test_run.c:36 #1: ffffffff8d32e720 (rcu_read_lock_bh){....}-{1:2}, at: local_bh_disable include/linux/bottom_half.h:20 [inline] #1: ffffffff8d32e720 (rcu_read_lock_bh){....}-{1:2}, at: rcu_read_lock_bh include/linux/rcupdate.h:843 [inline] #1: ffffffff8d32e720 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x2d6/0x3d50 net/core/dev.c:4257 #2: ffffffff8d32e6c0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #2: ffffffff8d32e6c0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #2: ffffffff8d32e6c0 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2283 [inline] #2: ffffffff8d32e6c0 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0x110/0x410 kernel/trace/bpf_trace.c:2323 #3: ffff888054098218 (&qs->lock){-.-.}-{2:2}, at: __queue_map_get+0x146/0x4b0 kernel/bpf/queue_stack_maps.c:109 #4: ffffffff8d32e6c0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #4: ffffffff8d32e6c0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #4: ffffffff8d32e6c0 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2283 [inline] #4: ffffffff8d32e6c0 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0x110/0x410 kernel/trace/bpf_trace.c:2323 stack backtrace: CPU: 0 PID: 8664 Comm: syz.7.1321 Not tainted 6.1.131-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 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 __queue_map_get+0x146/0x4b0 kernel/bpf/queue_stack_maps.c:109 bpf_prog_00798911c748094f+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_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 __queue_map_get+0x146/0x4b0 kernel/bpf/queue_stack_maps.c:109 bpf_prog_94b194d4ebfffdd5+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 __bpf_trace_kfree+0x6e/0x90 include/trace/events/kmem.h:94 trace_kfree include/trace/events/kmem.h:94 [inline] kfree+0xf6/0x190 mm/slab_common.c:975 skb_free_head net/core/skbuff.c:762 [inline] pskb_expand_head+0x450/0x1350 net/core/skbuff.c:1880 __skb_cow include/linux/skbuff.h:3585 [inline] skb_cow_head include/linux/skbuff.h:3619 [inline] ip_tunnel_xmit+0x183d/0x2550 net/ipv4/ip_tunnel.c:849 __gre_xmit net/ipv4/ip_gre.c:474 [inline] ipgre_xmit+0x82f/0xbe0 net/ipv4/ip_gre.c:669 __netdev_start_xmit include/linux/netdevice.h:4896 [inline] netdev_start_xmit include/linux/netdevice.h:4910 [inline] xmit_one net/core/dev.c:3658 [inline] dev_hard_start_xmit+0x261/0x8c0 net/core/dev.c:3674 __dev_queue_xmit+0x1b5d/0x3d50 net/core/dev.c:4334 dev_queue_xmit include/linux/netdevice.h:3051 [inline] __bpf_tx_skb net/core/filter.c:2125 [inline] __bpf_redirect_no_mac net/core/filter.c:2159 [inline] __bpf_redirect+0x907/0x1190 net/core/filter.c:2182 ____bpf_clone_redirect net/core/filter.c:2455 [inline] bpf_clone_redirect+0x26b/0x3c0 net/core/filter.c:2425 bpf_prog_973cd02a7a0e8181+0x56/0x5b 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_test_run+0x40f/0x8b0 net/bpf/test_run.c:402 bpf_prog_test_run_skb+0xaf1/0x13a0 net/bpf/test_run.c:1183 bpf_prog_test_run+0x32f/0x3a0 kernel/bpf/syscall.c:3682 __sys_bpf+0x3eb/0x6c0 kernel/bpf/syscall.c:5035 __do_sys_bpf kernel/bpf/syscall.c:5121 [inline] __se_sys_bpf kernel/bpf/syscall.c:5119 [inline] __x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:5119 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fad5958d169 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:00007fad5a306038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007fad597a5fa0 RCX: 00007fad5958d169 RDX: 000000000000002c RSI: 0000400000000080 RDI: 000000000000000a RBP: 00007fad5960e2a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fad597a5fa0 R15: 00007ffec54b9738