======================================================
WARNING: possible circular locking dependency detected
5.15.173-syzkaller #0 Not tainted
------------------------------------------------------
syz.0.20/4303 is trying to acquire lock:
ffff8880b8f27e78 (krc.lock){..-.}-{2:2}, at: krc_this_cpu_lock kernel/rcu/tree.c:3199 [inline]
ffff8880b8f27e78 (krc.lock){..-.}-{2:2}, at: add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3506 [inline]
ffff8880b8f27e78 (krc.lock){..-.}-{2:2}, at: kvfree_call_rcu+0x1b5/0x8a0 kernel/rcu/tree.c:3597

but task is already holding lock:
ffff88805e45f9b8 (&trie->lock){-.-.}-{2:2}, at: trie_delete_elem+0x90/0x690 kernel/bpf/lpm_trie.c:450

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&trie->lock){-.-.}-{2:2}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       __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:450
       0xffffffffa0028e75
       bpf_dispatcher_nop_func include/linux/bpf.h:790 [inline]
       __bpf_prog_run include/linux/filter.h:628 [inline]
       bpf_prog_run include/linux/filter.h:635 [inline]
       __bpf_trace_run kernel/trace/bpf_trace.c:1878 [inline]
       bpf_trace_run3+0x1d1/0x380 kernel/trace/bpf_trace.c:1916
       trace_timer_start include/trace/events/timer.h:52 [inline]
       enqueue_timer+0x3ae/0x540 kernel/time/timer.c:586
       internal_add_timer kernel/time/timer.c:611 [inline]
       __mod_timer+0xa60/0xeb0 kernel/time/timer.c:1062
       queue_delayed_work_on+0x156/0x250 kernel/workqueue.c:1715
       process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310
       worker_thread+0xaca/0x1280 kernel/workqueue.c:2457
       kthread+0x3f6/0x4f0 kernel/kthread.c:334
       ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

-> #1 (&base->lock){-.-.}-{2:2}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162
       lock_timer_base+0x120/0x260 kernel/time/timer.c:946
       __mod_timer+0x1d6/0xeb0 kernel/time/timer.c:1019
       queue_delayed_work_on+0x156/0x250 kernel/workqueue.c:1715
       queue_delayed_work include/linux/workqueue.h:527 [inline]
       schedule_delayed_work include/linux/workqueue.h:631 [inline]
       kvfree_call_rcu+0x50e/0x8a0 kernel/rcu/tree.c:3625
       rtnl_register_internal+0x443/0x530 net/core/rtnetlink.c:223
       rtnl_register+0x32/0x70 net/core/rtnetlink.c:273
       ip_rt_init+0x2e6/0x390 net/ipv4/route.c:3750
       ip_init+0xa/0x20 net/ipv4/ip_output.c:1749
       inet_init+0x27c/0x390 net/ipv4/af_inet.c:2009
       do_one_initcall+0x22b/0x7a0 init/main.c:1302
       do_initcall_level+0x157/0x210 init/main.c:1375
       do_initcalls+0x49/0x90 init/main.c:1391
       kernel_init_freeable+0x425/0x5c0 init/main.c:1615
       kernel_init+0x19/0x290 init/main.c:1506
       ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

-> #0 (krc.lock){..-.}-{2:2}:
       check_prev_add kernel/locking/lockdep.c:3053 [inline]
       check_prevs_add kernel/locking/lockdep.c:3172 [inline]
       validate_chain+0x1649/0x5930 kernel/locking/lockdep.c:3788
       __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
       _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154
       krc_this_cpu_lock kernel/rcu/tree.c:3199 [inline]
       add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3506 [inline]
       kvfree_call_rcu+0x1b5/0x8a0 kernel/rcu/tree.c:3597
       trie_delete_elem+0x520/0x690
       bpf_prog_8c8ab8634bca3061+0x3a/0x380
       bpf_dispatcher_nop_func include/linux/bpf.h:790 [inline]
       __bpf_prog_run include/linux/filter.h:628 [inline]
       bpf_prog_run include/linux/filter.h:635 [inline]
       __bpf_trace_run kernel/trace/bpf_trace.c:1878 [inline]
       bpf_trace_run3+0x1d1/0x380 kernel/trace/bpf_trace.c:1916
       __bpf_trace_kmem_cache_free+0x99/0xc0 include/trace/events/kmem.h:138
       __traceiter_kmem_cache_free+0x2e/0x50 include/trace/events/kmem.h:138
       trace_kmem_cache_free include/trace/events/kmem.h:138 [inline]
       kmem_cache_free+0x1ce/0x1f0 mm/slub.c:3516
       netlink_broadcast_filtered+0x1083/0x11a0 net/netlink/af_netlink.c:1536
       netlink_broadcast net/netlink/af_netlink.c:1558 [inline]
       nlmsg_multicast include/net/netlink.h:1033 [inline]
       nlmsg_notify+0xf7/0x1b0 net/netlink/af_netlink.c:2547
       fib6_del_route net/ipv6/ip6_fib.c:1996 [inline]
       fib6_del+0x109b/0x1570 net/ipv6/ip6_fib.c:2031
       fib6_clean_node+0x2ed/0x5d0 net/ipv6/ip6_fib.c:2193
       fib6_walk_continue+0x636/0x8c0 net/ipv6/ip6_fib.c:2115
       fib6_walk+0x168/0x2b0 net/ipv6/ip6_fib.c:2163
       fib6_clean_tree net/ipv6/ip6_fib.c:2243 [inline]
       __fib6_clean_all+0x2f8/0x480 net/ipv6/ip6_fib.c:2259
       rt6_sync_down_dev net/ipv6/route.c:4907 [inline]
       rt6_disable_ip+0x15d/0x6c0 net/ipv6/route.c:4912
       addrconf_ifdown+0x161/0x1bb0 net/ipv6/addrconf.c:3778
       addrconf_notify+0x432/0xf30
       notifier_call_chain kernel/notifier.c:83 [inline]
       raw_notifier_call_chain+0xd0/0x170 kernel/notifier.c:391
       call_netdevice_notifiers_info net/core/dev.c:2018 [inline]
       call_netdevice_notifiers_extack net/core/dev.c:2030 [inline]
       call_netdevice_notifiers net/core/dev.c:2044 [inline]
       dev_close_many+0x37c/0x530 net/core/dev.c:1619
       vlan_device_event+0x168d/0x1dd0 net/8021q/vlan.c:450
       notifier_call_chain kernel/notifier.c:83 [inline]
       raw_notifier_call_chain+0xd0/0x170 kernel/notifier.c:391
       __dev_notify_flags+0x304/0x610
       dev_change_flags+0xe7/0x190 net/core/dev.c:8897
       dev_ifsioc+0x147/0x10c0 net/core/dev_ioctl.c:324
       dev_ioctl+0x504/0xf60 net/core/dev_ioctl.c:587
       sock_do_ioctl+0x34f/0x5a0 net/socket.c:1154
       sock_ioctl+0x47f/0x770 net/socket.c:1257
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:874 [inline]
       __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:860
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

other info that might help us debug this:

Chain exists of:
  krc.lock --> &base->lock --> &trie->lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&trie->lock);
                               lock(&base->lock);
                               lock(&trie->lock);
  lock(krc.lock);

 *** DEADLOCK ***

5 locks held by syz.0.20/4303:
 #0: ffffffff8dc41388 (rtnl_mutex){+.+.}-{3:3}, at: dev_ioctl+0x4f1/0xf60 net/core/dev_ioctl.c:586
 #1: ffffffff8cb1fc60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:312
 #2: ffff8880291d1030 (&tb->tb6_lock){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:368 [inline]
 #2: ffff8880291d1030 (&tb->tb6_lock){+...}-{2:2}, at: __fib6_clean_all+0x1e1/0x480 net/ipv6/ip6_fib.c:2258
 #3: ffffffff8cb1fc60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:311
 #4: ffff88805e45f9b8 (&trie->lock){-.-.}-{2:2}, at: trie_delete_elem+0x90/0x690 kernel/bpf/lpm_trie.c:450

stack backtrace:
CPU: 1 PID: 4303 Comm: syz.0.20 Not tainted 5.15.173-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106
 check_noncircular+0x2f8/0x3b0 kernel/locking/lockdep.c:2133
 check_prev_add kernel/locking/lockdep.c:3053 [inline]
 check_prevs_add kernel/locking/lockdep.c:3172 [inline]
 validate_chain+0x1649/0x5930 kernel/locking/lockdep.c:3788
 __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012
 lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
 _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154
 krc_this_cpu_lock kernel/rcu/tree.c:3199 [inline]
 add_ptr_to_bulk_krc_lock kernel/rcu/tree.c:3506 [inline]
 kvfree_call_rcu+0x1b5/0x8a0 kernel/rcu/tree.c:3597
 trie_delete_elem+0x520/0x690
 bpf_prog_8c8ab8634bca3061+0x3a/0x380
 bpf_dispatcher_nop_func include/linux/bpf.h:790 [inline]
 __bpf_prog_run include/linux/filter.h:628 [inline]
 bpf_prog_run include/linux/filter.h:635 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:1878 [inline]
 bpf_trace_run3+0x1d1/0x380 kernel/trace/bpf_trace.c:1916
 __bpf_trace_kmem_cache_free+0x99/0xc0 include/trace/events/kmem.h:138
 __traceiter_kmem_cache_free+0x2e/0x50 include/trace/events/kmem.h:138
 trace_kmem_cache_free include/trace/events/kmem.h:138 [inline]
 kmem_cache_free+0x1ce/0x1f0 mm/slub.c:3516
 netlink_broadcast_filtered+0x1083/0x11a0 net/netlink/af_netlink.c:1536
 netlink_broadcast net/netlink/af_netlink.c:1558 [inline]
 nlmsg_multicast include/net/netlink.h:1033 [inline]
 nlmsg_notify+0xf7/0x1b0 net/netlink/af_netlink.c:2547
 fib6_del_route net/ipv6/ip6_fib.c:1996 [inline]
 fib6_del+0x109b/0x1570 net/ipv6/ip6_fib.c:2031
 fib6_clean_node+0x2ed/0x5d0 net/ipv6/ip6_fib.c:2193
 fib6_walk_continue+0x636/0x8c0 net/ipv6/ip6_fib.c:2115
 fib6_walk+0x168/0x2b0 net/ipv6/ip6_fib.c:2163
 fib6_clean_tree net/ipv6/ip6_fib.c:2243 [inline]
 __fib6_clean_all+0x2f8/0x480 net/ipv6/ip6_fib.c:2259
 rt6_sync_down_dev net/ipv6/route.c:4907 [inline]
 rt6_disable_ip+0x15d/0x6c0 net/ipv6/route.c:4912
 addrconf_ifdown+0x161/0x1bb0 net/ipv6/addrconf.c:3778
 addrconf_notify+0x432/0xf30
 notifier_call_chain kernel/notifier.c:83 [inline]
 raw_notifier_call_chain+0xd0/0x170 kernel/notifier.c:391
 call_netdevice_notifiers_info net/core/dev.c:2018 [inline]
 call_netdevice_notifiers_extack net/core/dev.c:2030 [inline]
 call_netdevice_notifiers net/core/dev.c:2044 [inline]
 dev_close_many+0x37c/0x530 net/core/dev.c:1619
 vlan_device_event+0x168d/0x1dd0 net/8021q/vlan.c:450
 notifier_call_chain kernel/notifier.c:83 [inline]
 raw_notifier_call_chain+0xd0/0x170 kernel/notifier.c:391
 __dev_notify_flags+0x304/0x610
 dev_change_flags+0xe7/0x190 net/core/dev.c:8897
 dev_ifsioc+0x147/0x10c0 net/core/dev_ioctl.c:324
 dev_ioctl+0x504/0xf60 net/core/dev_ioctl.c:587
 sock_do_ioctl+0x34f/0x5a0 net/socket.c:1154
 sock_ioctl+0x47f/0x770 net/socket.c:1257
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:860
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f20146b0d19
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:00007f2012521038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f20148a0fa0 RCX: 00007f20146b0d19
RDX: 0000000020000000 RSI: 0000000000008914 RDI: 0000000000000004
RBP: 00007f201472ca20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f20148a0fa0 R15: 00007ffd89ae36a8
 </TASK>