=============================
WARNING: suspicious RCU usage
6.15.0-rc5-syzkaller-00022-g01f95500a162 #0 Not tainted
-----------------------------
net/ipv6/ip6_fib.c:1351 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.3.3561/20581:
#0: ffffffff8f2f4808 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#0: ffffffff8f2f4808 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
#0: ffffffff8f2f4808 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8db/0x1c70 net/core/rtnetlink.c:4064
#1: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#1: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#1: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: __fib6_clean_all+0x9b/0x380 net/ipv6/ip6_fib.c:2263
#2: ffff888059ab1c30 (&tb->tb6_lock){+...}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:356 [inline]
#2: ffff888059ab1c30 (&tb->tb6_lock){+...}-{3:3}, at: __fib6_clean_all+0x1ce/0x380 net/ipv6/ip6_fib.c:2267
stack backtrace:
CPU: 0 UID: 0 PID: 20581 Comm: syz.3.3561 Not tainted 6.15.0-rc5-syzkaller-00022-g01f95500a162 #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/29/2025
Call Trace:
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
lockdep_rcu_suspicious+0x140/0x1d0 kernel/locking/lockdep.c:6865
__fib6_update_sernum_upto_root+0x223/0x230 net/ipv6/ip6_fib.c:1350
fib6_update_sernum_upto_root+0x125/0x190 net/ipv6/ip6_fib.c:1364
fib6_ifup+0x142/0x180 net/ipv6/route.c:4818
fib6_clean_node+0x24a/0x590 net/ipv6/ip6_fib.c:2199
fib6_walk_continue+0x678/0x910 net/ipv6/ip6_fib.c:2124
fib6_walk+0x149/0x290 net/ipv6/ip6_fib.c:2172
fib6_clean_tree net/ipv6/ip6_fib.c:2252 [inline]
__fib6_clean_all+0x234/0x380 net/ipv6/ip6_fib.c:2268
rt6_sync_up+0x128/0x160 net/ipv6/route.c:4837
addrconf_notify+0xd55/0x1010 net/ipv6/addrconf.c:3729
notifier_call_chain+0x1b3/0x3e0 kernel/notifier.c:85
netif_state_change+0x284/0x3a0 net/core/dev.c:1530
do_setlink+0x2eb6/0x40d0 net/core/rtnetlink.c:3399
rtnl_group_changelink net/core/rtnetlink.c:3783 [inline]
__rtnl_newlink net/core/rtnetlink.c:3937 [inline]
rtnl_newlink+0x149f/0x1c70 net/core/rtnetlink.c:4065
rtnetlink_rcv_msg+0x7cc/0xb70 net/core/rtnetlink.c:6955
netlink_rcv_skb+0x219/0x490 net/netlink/af_netlink.c:2534
netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
netlink_unicast+0x758/0x8d0 net/netlink/af_netlink.c:1339
netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1883
sock_sendmsg_nosec net/socket.c:712 [inline]
__sock_sendmsg+0x219/0x270 net/socket.c:727
____sys_sendmsg+0x505/0x830 net/socket.c:2566
___sys_sendmsg+0x21f/0x2a0 net/socket.c:2620
__sys_sendmsg+0x164/0x220 net/socket.c:2652
do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
__do_fast_syscall_32+0xb4/0x110 arch/x86/entry/syscall_32.c:306
do_fast_syscall_32+0x34/0x80 arch/x86/entry/syscall_32.c:331
entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf707e539
Code: 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 002b:00000000f4c0955c EFLAGS: 00000206 ORIG_RAX: 0000000000000172
RAX: ffffffffffffffda RBX: 0000000000000007 RCX: 0000000080000380
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
=============================
WARNING: suspicious RCU usage
6.15.0-rc5-syzkaller-00022-g01f95500a162 #0 Not tainted
-----------------------------
net/ipv6/ip6_fib.c:1358 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.3.3561/20581:
#0: ffffffff8f2f4808 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#0: ffffffff8f2f4808 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
#0: ffffffff8f2f4808 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8db/0x1c70 net/core/rtnetlink.c:4064
#1: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#1: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#1: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: __fib6_clean_all+0x9b/0x380 net/ipv6/ip6_fib.c:2263
#2: ffff888059ab1c30 (&tb->tb6_lock){+...}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:356 [inline]
#2: ffff888059ab1c30 (&tb->tb6_lock){+...}-{3:3}, at: __fib6_clean_all+0x1ce/0x380 net/ipv6/ip6_fib.c:2267
stack backtrace:
CPU: 0 UID: 0 PID: 20581 Comm: syz.3.3561 Not tainted 6.15.0-rc5-syzkaller-00022-g01f95500a162 #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/29/2025
Call Trace:
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
lockdep_rcu_suspicious+0x140/0x1d0 kernel/locking/lockdep.c:6865
__fib6_update_sernum_upto_root+0x18e/0x230 net/ipv6/ip6_fib.c:1357
fib6_update_sernum_upto_root+0x125/0x190 net/ipv6/ip6_fib.c:1364
fib6_ifup+0x142/0x180 net/ipv6/route.c:4818
fib6_clean_node+0x24a/0x590 net/ipv6/ip6_fib.c:2199
fib6_walk_continue+0x678/0x910 net/ipv6/ip6_fib.c:2124
fib6_walk+0x149/0x290 net/ipv6/ip6_fib.c:2172
fib6_clean_tree net/ipv6/ip6_fib.c:2252 [inline]
__fib6_clean_all+0x234/0x380 net/ipv6/ip6_fib.c:2268
rt6_sync_up+0x128/0x160 net/ipv6/route.c:4837
addrconf_notify+0xd55/0x1010 net/ipv6/addrconf.c:3729
notifier_call_chain+0x1b3/0x3e0 kernel/notifier.c:85
netif_state_change+0x284/0x3a0 net/core/dev.c:1530
do_setlink+0x2eb6/0x40d0 net/core/rtnetlink.c:3399
rtnl_group_changelink net/core/rtnetlink.c:3783 [inline]
__rtnl_newlink net/core/rtnetlink.c:3937 [inline]
rtnl_newlink+0x149f/0x1c70 net/core/rtnetlink.c:4065
rtnetlink_rcv_msg+0x7cc/0xb70 net/core/rtnetlink.c:6955
netlink_rcv_skb+0x219/0x490 net/netlink/af_netlink.c:2534
netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
netlink_unicast+0x758/0x8d0 net/netlink/af_netlink.c:1339
netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1883
sock_sendmsg_nosec net/socket.c:712 [inline]
__sock_sendmsg+0x219/0x270 net/socket.c:727
____sys_sendmsg+0x505/0x830 net/socket.c:2566
___sys_sendmsg+0x21f/0x2a0 net/socket.c:2620
__sys_sendmsg+0x164/0x220 net/socket.c:2652
do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
__do_fast_syscall_32+0xb4/0x110 arch/x86/entry/syscall_32.c:306
do_fast_syscall_32+0x34/0x80 arch/x86/entry/syscall_32.c:331
entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf707e539
Code: 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 002b:00000000f4c0955c EFLAGS: 00000206 ORIG_RAX: 0000000000000172
RAX: ffffffffffffffda RBX: 0000000000000007 RCX: 0000000080000380
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
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
bond_slave_0: left allmulticast mode
bond0: (slave bond_slave_1): Releasing backup interface
bond_slave_1: left allmulticast mode
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
----------------
Code disassembly (best guess):
0: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi
4: 10 07 adc %al,(%rdi)
6: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi
a: 10 08 adc %cl,(%rax)
c: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi
20: 00 51 52 add %dl,0x52(%rcx)
23: 55 push %rbp
24: 89 e5 mov %esp,%ebp
26: 0f 34 sysenter
28: cd 80 int $0x80
* 2a: 5d pop %rbp <-- trapping instruction
2b: 5a pop %rdx
2c: 59 pop %rcx
2d: c3 ret
2e: 90 nop
2f: 90 nop
30: 90 nop
31: 90 nop
32: 90 nop
33: 90 nop
34: 90 nop
35: 90 nop
36: 90 nop
37: 90 nop
38: 90 nop
39: 90 nop
3a: 90 nop
3b: 90 nop
3c: 90 nop
3d: 90 nop
3e: 90 nop
3f: 90 nop