syzbot

======================================================
WARNING: possible circular locking dependency detected
6.1.131-syzkaller #0 Not tainted
------------------------------------------------------
syz.4.142/4903 is trying to acquire lock:
ffff888017c43318 (&n->list_lock){-.-.}-{2:2}, at: get_partial_node+0x36/0x450 mm/slub.c:2210

but task is already holding lock:
ffff888077fafa38 (&trie->lock){-.-.}-{2:2}, at: trie_update_elem+0xc6/0xdc0 kernel/bpf/lpm_trie.c:335

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&trie->lock){-.-.}-{2:2}:
       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
       trie_delete_elem+0x90/0x690 kernel/bpf/lpm_trie.c:467
       bpf_prog_8bb90853150cd06d+0x27/0x41
       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
       get_partial_node+0x36/0x450 mm/slub.c:2210
       get_partial mm/slub.c:2325 [inline]
       ___slab_alloc+0x9b2/0x1270 mm/slub.c:3175
       __slab_alloc mm/slub.c:3279 [inline]
       slab_alloc_node mm/slub.c:3364 [inline]
       __kmem_cache_alloc_node+0x19f/0x260 mm/slub.c:3437
       kmalloc_trace+0x26/0xe0 mm/slab_common.c:1026
       kmalloc include/linux/slab.h:563 [inline]
       kzalloc include/linux/slab.h:699 [inline]
       kobject_uevent_env+0x281/0x8c0 lib/kobject_uevent.c:539
       netdev_queue_add_kobject net/core/net-sysfs.c:1675 [inline]
       netdev_queue_update_kobjects+0x22d/0x480 net/core/net-sysfs.c:1716
       register_queue_kobjects net/core/net-sysfs.c:1777 [inline]
       netdev_register_kobject+0x263/0x310 net/core/net-sysfs.c:2017
       register_netdevice+0x12ad/0x1ab0 net/core/dev.c:10192
       cfg80211_register_netdevice+0x14e/0x2e0 net/wireless/core.c:1447
       ieee80211_if_add+0xcc6/0x1940 net/mac80211/iface.c:2297
       ieee80211_register_hw+0x32ff/0x3f10 net/mac80211/main.c:1402
       mac80211_hwsim_new_radio+0x2355/0x41c0 drivers/net/wireless/mac80211_hwsim.c:4582
       hwsim_new_radio_nl+0xc54/0x1190 drivers/net/wireless/mac80211_hwsim.c:5176
       genl_family_rcv_msg_doit net/netlink/genetlink.c:756 [inline]
       genl_family_rcv_msg net/netlink/genetlink.c:833 [inline]
       genl_rcv_msg+0xbfa/0xf50 net/netlink/genetlink.c:850
       netlink_rcv_skb+0x1cd/0x410 net/netlink/af_netlink.c:2493
       genl_rcv+0x24/0x40 net/netlink/genetlink.c:861
       netlink_unicast_kernel net/netlink/af_netlink.c:1311 [inline]
       netlink_unicast+0x7e2/0x970 net/netlink/af_netlink.c:1337
       netlink_sendmsg+0xa26/0xd60 net/netlink/af_netlink.c:1859
       sock_sendmsg_nosec net/socket.c:718 [inline]
       __sock_sendmsg net/socket.c:730 [inline]
       __sys_sendto+0x480/0x600 net/socket.c:2153
       __do_sys_sendto net/socket.c:2165 [inline]
       __se_sys_sendto net/socket.c:2161 [inline]
       __x64_sys_sendto+0xda/0xf0 net/socket.c:2161
       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

-> #0 (&n->list_lock){-.-.}-{2:2}:
       check_prev_add kernel/locking/lockdep.c:3090 [inline]
       check_prevs_add kernel/locking/lockdep.c:3209 [inline]
       validate_chain+0x1661/0x5950 kernel/locking/lockdep.c:3825
       __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
       get_partial_node+0x36/0x450 mm/slub.c:2210
       get_partial mm/slub.c:2325 [inline]
       ___slab_alloc+0x9b2/0x1270 mm/slub.c:3175
       __slab_alloc mm/slub.c:3279 [inline]
       slab_alloc_node mm/slub.c:3364 [inline]
       __kmem_cache_alloc_node+0x19f/0x260 mm/slub.c:3437
       __do_kmalloc_node mm/slab_common.c:935 [inline]
       __kmalloc_node+0xa2/0x230 mm/slab_common.c:943
       kmalloc_node include/linux/slab.h:589 [inline]
       bpf_map_kmalloc_node+0xce/0x1c0 kernel/bpf/syscall.c:452
       lpm_trie_node_alloc kernel/bpf/lpm_trie.c:291 [inline]
       trie_update_elem+0x175/0xdc0 kernel/bpf/lpm_trie.c:338
       bpf_map_update_value+0x5cf/0x6f0 kernel/bpf/syscall.c:226
       map_update_elem+0x503/0x680 kernel/bpf/syscall.c:1463
       __sys_bpf+0x337/0x6c0 kernel/bpf/syscall.c:5005
       __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

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&trie->lock);
                               lock(&n->list_lock);
                               lock(&trie->lock);
  lock(&n->list_lock);

 *** DEADLOCK ***

2 locks held by syz.4.142/4903:
 #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_map_update_value+0x207/0x6f0 kernel/bpf/syscall.c:225
 #1: ffff888077fafa38 (&trie->lock){-.-.}-{2:2}, at: trie_update_elem+0xc6/0xdc0 kernel/bpf/lpm_trie.c:335

stack backtrace:
CPU: 1 PID: 4903 Comm: syz.4.142 Not tainted 6.1.131-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 check_noncircular+0x2fa/0x3b0 kernel/locking/lockdep.c:2170
 check_prev_add kernel/locking/lockdep.c:3090 [inline]
 check_prevs_add kernel/locking/lockdep.c:3209 [inline]
 validate_chain+0x1661/0x5950 kernel/locking/lockdep.c:3825
 __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
 get_partial_node+0x36/0x450 mm/slub.c:2210
 get_partial mm/slub.c:2325 [inline]
 ___slab_alloc+0x9b2/0x1270 mm/slub.c:3175
 __slab_alloc mm/slub.c:3279 [inline]
 slab_alloc_node mm/slub.c:3364 [inline]
 __kmem_cache_alloc_node+0x19f/0x260 mm/slub.c:3437
 __do_kmalloc_node mm/slab_common.c:935 [inline]
 __kmalloc_node+0xa2/0x230 mm/slab_common.c:943
 kmalloc_node include/linux/slab.h:589 [inline]
 bpf_map_kmalloc_node+0xce/0x1c0 kernel/bpf/syscall.c:452
 lpm_trie_node_alloc kernel/bpf/lpm_trie.c:291 [inline]
 trie_update_elem+0x175/0xdc0 kernel/bpf/lpm_trie.c:338
 bpf_map_update_value+0x5cf/0x6f0 kernel/bpf/syscall.c:226
 map_update_elem+0x503/0x680 kernel/bpf/syscall.c:1463
 __sys_bpf+0x337/0x6c0 kernel/bpf/syscall.c:5005
 __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: 0033:0x7f922d98d169
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:00007f922e798038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007f922dba5fa0 RCX: 00007f922d98d169
RDX: 0000000000000020 RSI: 00002000000004c0 RDI: 0000000000000002
RBP: 00007f922da0e2a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f922dba5fa0 R15: 00007ffd681b0ec8
 </TASK>