=============================
WARNING: suspicious RCU usage
6.15.0-syzkaller-09161-g0f70f5b08a47 #0 Not tainted
-----------------------------
net/ipv6/ip6_fib.c:1393 suspicious rcu_dereference_protected() usage!
other info that might help us debug this:
rcu_scheduler_active = 2, debug_locks = 1
3 locks held by syz.3.4271/5383:
#0: ffffffff90344628 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#0: ffffffff90344628 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
#0: ffffffff90344628 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x600/0x2000 net/core/rtnetlink.c:4054
#1: ffffffff8e5c4780 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#1: ffffffff8e5c4780 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#1: ffffffff8e5c4780 (rcu_read_lock){....}-{1:3}, at: __fib6_clean_all+0x3a/0x2d0 net/ipv6/ip6_fib.c:2316
#2: ffff88806745d430 (&tb->tb6_lock){+...}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:356 [inline]
#2: ffff88806745d430 (&tb->tb6_lock){+...}-{3:3}, at: __fib6_clean_all+0xeb/0x2d0 net/ipv6/ip6_fib.c:2320
stack backtrace:
CPU: 0 UID: 0 PID: 5383 Comm: syz.3.4271 Not tainted 6.15.0-syzkaller-09161-g0f70f5b08a47 #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x16c/0x1f0 lib/dump_stack.c:120
lockdep_rcu_suspicious+0x166/0x260 kernel/locking/lockdep.c:6871
__fib6_update_sernum_upto_root+0x221/0x270 net/ipv6/ip6_fib.c:1393
fib6_ifup+0x19b/0x2a0 net/ipv6/route.c:4871
fib6_clean_node+0x2a4/0x5b0 net/ipv6/ip6_fib.c:2252
fib6_walk_continue+0x44f/0x8d0 net/ipv6/ip6_fib.c:2177
fib6_walk+0x182/0x370 net/ipv6/ip6_fib.c:2225
fib6_clean_tree+0xd4/0x110 net/ipv6/ip6_fib.c:2305
__fib6_clean_all+0x107/0x2d0 net/ipv6/ip6_fib.c:2321
rt6_sync_up+0xc9/0x170 net/ipv6/route.c:4890
addrconf_notify+0x1709/0x19e0 net/ipv6/addrconf.c:3732
notifier_call_chain+0xb9/0x410 kernel/notifier.c:85
call_netdevice_notifiers_info+0xbe/0x140 net/core/dev.c:2230
netif_state_change+0x165/0x3b0 net/core/dev.c:1584
do_setlink.constprop.0+0x3570/0x4380 net/core/rtnetlink.c:3388
rtnl_group_changelink net/core/rtnetlink.c:3773 [inline]
__rtnl_newlink net/core/rtnetlink.c:3927 [inline]
rtnl_newlink+0x18e0/0x2000 net/core/rtnetlink.c:4055
rtnetlink_rcv_msg+0x95b/0xe90 net/core/rtnetlink.c:6944
netlink_rcv_skb+0x155/0x420 net/netlink/af_netlink.c:2534
netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
netlink_unicast+0x53d/0x7f0 net/netlink/af_netlink.c:1339
netlink_sendmsg+0x8d1/0xdd0 net/netlink/af_netlink.c:1883
sock_sendmsg_nosec net/socket.c:712 [inline]
__sock_sendmsg net/socket.c:727 [inline]
____sys_sendmsg+0xa98/0xc70 net/socket.c:2566
___sys_sendmsg+0x134/0x1d0 net/socket.c:2620
__sys_sendmsg+0x16d/0x220 net/socket.c:2652
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7eff3658e969
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:00007eff37336038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007eff367b5fa0 RCX: 00007eff3658e969
RDX: 0000000000000000 RSI: 0000200000000280 RDI: 0000000000000007
RBP: 00007eff36610ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007eff367b5fa0 R15: 00007fff40b9e4f8
=============================
WARNING: suspicious RCU usage
6.15.0-syzkaller-09161-g0f70f5b08a47 #0 Not tainted
-----------------------------
net/ipv6/ip6_fib.c:1400 suspicious rcu_dereference_protected() usage!
other info that might help us debug this:
rcu_scheduler_active = 2, debug_locks = 1
3 locks held by syz.3.4271/5383:
#0: ffffffff90344628 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#0: ffffffff90344628 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
#0: ffffffff90344628 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x600/0x2000 net/core/rtnetlink.c:4054
#1: ffffffff8e5c4780 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#1: ffffffff8e5c4780 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#1: ffffffff8e5c4780 (rcu_read_lock){....}-{1:3}, at: __fib6_clean_all+0x3a/0x2d0 net/ipv6/ip6_fib.c:2316
#2: ffff88806745d430 (&tb->tb6_lock){+...}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:356 [inline]
#2: ffff88806745d430 (&tb->tb6_lock){+...}-{3:3}, at: __fib6_clean_all+0xeb/0x2d0 net/ipv6/ip6_fib.c:2320
stack backtrace:
CPU: 0 UID: 0 PID: 5383 Comm: syz.3.4271 Not tainted 6.15.0-syzkaller-09161-g0f70f5b08a47 #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x16c/0x1f0 lib/dump_stack.c:120
lockdep_rcu_suspicious+0x166/0x260 kernel/locking/lockdep.c:6871
__fib6_update_sernum_upto_root+0x16b/0x270 net/ipv6/ip6_fib.c:1400
fib6_ifup+0x19b/0x2a0 net/ipv6/route.c:4871
fib6_clean_node+0x2a4/0x5b0 net/ipv6/ip6_fib.c:2252
fib6_walk_continue+0x44f/0x8d0 net/ipv6/ip6_fib.c:2177
fib6_walk+0x182/0x370 net/ipv6/ip6_fib.c:2225
fib6_clean_tree+0xd4/0x110 net/ipv6/ip6_fib.c:2305
__fib6_clean_all+0x107/0x2d0 net/ipv6/ip6_fib.c:2321
rt6_sync_up+0xc9/0x170 net/ipv6/route.c:4890
addrconf_notify+0x1709/0x19e0 net/ipv6/addrconf.c:3732
notifier_call_chain+0xb9/0x410 kernel/notifier.c:85
call_netdevice_notifiers_info+0xbe/0x140 net/core/dev.c:2230
netif_state_change+0x165/0x3b0 net/core/dev.c:1584
do_setlink.constprop.0+0x3570/0x4380 net/core/rtnetlink.c:3388
rtnl_group_changelink net/core/rtnetlink.c:3773 [inline]
__rtnl_newlink net/core/rtnetlink.c:3927 [inline]
rtnl_newlink+0x18e0/0x2000 net/core/rtnetlink.c:4055
rtnetlink_rcv_msg+0x95b/0xe90 net/core/rtnetlink.c:6944
netlink_rcv_skb+0x155/0x420 net/netlink/af_netlink.c:2534
netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
netlink_unicast+0x53d/0x7f0 net/netlink/af_netlink.c:1339
netlink_sendmsg+0x8d1/0xdd0 net/netlink/af_netlink.c:1883
sock_sendmsg_nosec net/socket.c:712 [inline]
__sock_sendmsg net/socket.c:727 [inline]
____sys_sendmsg+0xa98/0xc70 net/socket.c:2566
___sys_sendmsg+0x134/0x1d0 net/socket.c:2620
__sys_sendmsg+0x16d/0x220 net/socket.c:2652
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7eff3658e969
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:00007eff37336038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007eff367b5fa0 RCX: 00007eff3658e969
RDX: 0000000000000000 RSI: 0000200000000280 RDI: 0000000000000007
RBP: 00007eff36610ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007eff367b5fa0 R15: 00007fff40b9e4f8
bridge_slave_0: left allmulticast mode
bridge_slave_0: left promiscuous mode
bridge0: port 1(bridge_slave_0) entered disabled state
bridge_slave_1: left allmulticast mode
bridge_slave_1: left promiscuous mode
bridge0: port 2(bridge_slave_1) entered disabled state
bond0: (slave bond_slave_0): Releasing backup interface
bond0: (slave bond_slave_1): Releasing backup interface
team0: Port device team_slave_0 removed
team0: Port device team_slave_1 removed
batman_adv: batadv0: Interface deactivated: batadv_slave_0
batman_adv: batadv0: Removing interface: batadv_slave_0
batman_adv: batadv0: Interface deactivated: batadv_slave_1
batman_adv: batadv0: Removing interface: batadv_slave_1