============================================
WARNING: possible recursive locking detected
syzkaller #0 Tainted: G L
--------------------------------------------
syz.7.6635/32054 is trying to acquire lock:
ffff8880339a1588 (&br->multicast_lock){+.-.}-{3:3}, at: spin_lock include/linux/spinlock.h:341 [inline]
ffff8880339a1588 (&br->multicast_lock){+.-.}-{3:3}, at: br_ip6_multicast_query net/bridge/br_multicast.c:3583 [inline]
ffff8880339a1588 (&br->multicast_lock){+.-.}-{3:3}, at: br_multicast_ipv6_rcv net/bridge/br_multicast.c:3979 [inline]
ffff8880339a1588 (&br->multicast_lock){+.-.}-{3:3}, at: br_multicast_rcv+0x2dda/0x7650 net/bridge/br_multicast.c:4034
but task is already holding lock:
ffff888054eb9588 (&br->multicast_lock){+.-.}-{3:3}, at: spin_lock include/linux/spinlock.h:341 [inline]
ffff888054eb9588 (&br->multicast_lock){+.-.}-{3:3}, at: br_multicast_port_query_expired net/bridge/br_multicast.c:1903 [inline]
ffff888054eb9588 (&br->multicast_lock){+.-.}-{3:3}, at: br_ip6_multicast_port_query_expired+0x6b/0x380 net/bridge/br_multicast.c:1931
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(&br->multicast_lock);
lock(&br->multicast_lock);
*** DEADLOCK ***
May be due to missing lock nesting notation
7 locks held by syz.7.6635/32054:
#0: ffffffff8f30bfc8 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#0: ffffffff8f30bfc8 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#0: ffffffff8f30bfc8 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570
#1: ffffffff8fbd0888 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#1: ffffffff8fbd0888 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
#1: ffffffff8fbd0888 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8a1/0x1be0 net/core/rtnetlink.c:4093
#2: ffffc90000a08ce0 ((&pmctx->ip6_own_query.timer)){+.-.}-{0:0}, at: call_timer_fn+0xd4/0x640 kernel/time/timer.c:1745
#3: ffff888054eb9588 (&br->multicast_lock){+.-.}-{3:3}, at: spin_lock include/linux/spinlock.h:341 [inline]
#3: ffff888054eb9588 (&br->multicast_lock){+.-.}-{3:3}, at: br_multicast_port_query_expired net/bridge/br_multicast.c:1903 [inline]
#3: ffff888054eb9588 (&br->multicast_lock){+.-.}-{3:3}, at: br_ip6_multicast_port_query_expired+0x6b/0x380 net/bridge/br_multicast.c:1931
#4: ffffffff8e75e600 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline]
#4: ffffffff8e75e600 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:903 [inline]
#4: ffffffff8e75e600 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x277/0x3890 net/core/dev.c:4778
#5: ffffffff8e75e600 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline]
#5: ffffffff8e75e600 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:903 [inline]
#5: ffffffff8e75e600 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x277/0x3890 net/core/dev.c:4778
#6: ffffffff8e75e5a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#6: ffffffff8e75e5a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#6: ffffffff8e75e5a0 (rcu_read_lock){....}-{1:3}, at: br_dev_xmit+0x193/0x1980 net/bridge/br_device.c:52
stack backtrace:
CPU: 1 UID: 0 PID: 32054 Comm: syz.7.6635 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
print_deadlock_bug+0x279/0x290 kernel/locking/lockdep.c:3041
check_deadlock kernel/locking/lockdep.c:3093 [inline]
validate_chain kernel/locking/lockdep.c:3895 [inline]
__lock_acquire+0x253f/0x2cf0 kernel/locking/lockdep.c:5237
lock_acquire+0xf0/0x2e0 kernel/locking/lockdep.c:5868
__raw_spin_lock include/linux/spinlock_api_smp.h:158 [inline]
_raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
spin_lock include/linux/spinlock.h:341 [inline]
br_ip6_multicast_query net/bridge/br_multicast.c:3583 [inline]
br_multicast_ipv6_rcv net/bridge/br_multicast.c:3979 [inline]
br_multicast_rcv+0x2dda/0x7650 net/bridge/br_multicast.c:4034
br_dev_xmit+0xb67/0x1980 net/bridge/br_device.c:98
__netdev_start_xmit include/linux/netdevice.h:5325 [inline]
netdev_start_xmit include/linux/netdevice.h:5334 [inline]
xmit_one net/core/dev.c:3888 [inline]
dev_hard_start_xmit+0x2d8/0x870 net/core/dev.c:3904
__dev_queue_xmit+0x16d1/0x3890 net/core/dev.c:4854
dev_queue_xmit_accel include/linux/netdevice.h:3391 [inline]
macvlan_queue_xmit drivers/net/macvlan.c:563 [inline]
macvlan_start_xmit+0x3ba/0x600 drivers/net/macvlan.c:587
__netdev_start_xmit include/linux/netdevice.h:5325 [inline]
netdev_start_xmit include/linux/netdevice.h:5334 [inline]
xmit_one net/core/dev.c:3888 [inline]
dev_hard_start_xmit+0x2d8/0x870 net/core/dev.c:3904
__dev_queue_xmit+0x16d1/0x3890 net/core/dev.c:4854
dev_queue_xmit include/linux/netdevice.h:3385 [inline]
br_dev_queue_push_xmit+0x370/0x4a0 net/bridge/br_forward.c:53
NF_HOOK include/linux/netfilter.h:318 [inline]
__br_multicast_send_query+0x2f4a/0x4630 net/bridge/br_multicast.c:1807
br_multicast_send_query+0x509/0x6b0 net/bridge/br_multicast.c:1886
br_multicast_port_query_expired net/bridge/br_multicast.c:1911 [inline]
br_ip6_multicast_port_query_expired+0x2b5/0x380 net/bridge/br_multicast.c:1931
call_timer_fn+0x192/0x640 kernel/time/timer.c:1748
expire_timers kernel/time/timer.c:1799 [inline]
__run_timers kernel/time/timer.c:2373 [inline]
__run_timer_base+0x652/0x8b0 kernel/time/timer.c:2385
run_timer_base kernel/time/timer.c:2394 [inline]
run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2404
handle_softirqs+0x22a/0x870 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0x5f/0x150 kernel/softirq.c:723
irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1056
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:__kasan_check_byte+0x12/0x40 mm/kasan/common.c:573
Code: ff 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 40 d6 41 56 53 48 89 f3 49 89 fe e8 8e 15 00 00 <84> c0 75 16 be 01 00 00 00 4c 89 f7 31 d2 48 89 d9 89 c3 e8 06 05
RSP: 0018:ffffc9000c95e588 EFLAGS: 00000293
RAX: 0000000000000001 RBX: ffffffff81768a72 RCX: 0000000080000001
RDX: 0000000000000000 RSI: ffffffff81768a72 RDI: 1ffffffff1cebcb4
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: ffffc9000c95e738 R11: ffffffff81b0dbf0 R12: 0000000000000002
R13: ffffffff8e75e5a0 R14: ffffffff8e75e5a0 R15: 0000000000000000
kasan_check_byte include/linux/kasan.h:402 [inline]
lock_acquire+0x79/0x2e0 kernel/locking/lockdep.c:5842
rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
rcu_read_lock include/linux/rcupdate.h:850 [inline]
class_rcu_constructor include/linux/rcupdate.h:1193 [inline]
unwind_next_frame+0xc2/0x23c0 arch/x86/kernel/unwind_orc.c:495
arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
__kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
kasan_kmalloc include/linux/kasan.h:263 [inline]
__do_kmalloc_node mm/slub.c:5260 [inline]
__kmalloc_node_track_caller_noprof+0x4db/0x7b0 mm/slub.c:5368
kmalloc_reserve net/core/skbuff.c:635 [inline]
__alloc_skb+0x2c1/0x7d0 net/core/skbuff.c:713
alloc_skb include/linux/skbuff.h:1383 [inline]
nlmsg_new include/net/netlink.h:1055 [inline]
rtmsg_ifinfo_build_skb+0x84/0x260 net/core/rtnetlink.c:4429
rtmsg_ifinfo_event net/core/rtnetlink.c:4471 [inline]
rtnetlink_event+0x1b7/0x270 net/core/rtnetlink.c:7040
notifier_call_chain+0x1be/0x400 kernel/notifier.c:85
call_netdevice_notifiers_extack net/core/dev.c:2287 [inline]
call_netdevice_notifiers net/core/dev.c:2301 [inline]
netdev_features_change net/core/dev.c:1590 [inline]
netdev_change_features net/core/dev.c:11126 [inline]
netdev_compute_master_upper_features+0x91e/0xac0 net/core/dev.c:12880
br_add_if+0xc1a/0xeb0 net/bridge/br_if.c:683
do_set_master+0x533/0x6d0 net/core/rtnetlink.c:2985
rtnl_newlink_create+0x6af/0xb70 net/core/rtnetlink.c:3876
__rtnl_newlink net/core/rtnetlink.c:3979 [inline]
rtnl_newlink+0x1666/0x1be0 net/core/rtnetlink.c:4094
rtnetlink_rcv_msg+0x7d5/0xbe0 net/core/rtnetlink.c:6980
netlink_rcv_skb+0x232/0x4b0 net/netlink/af_netlink.c:2550
netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
netlink_unicast+0x80f/0x9b0 net/netlink/af_netlink.c:1344
netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1894
sock_sendmsg_nosec net/socket.c:727 [inline]
__sock_sendmsg net/socket.c:742 [inline]
____sys_sendmsg+0x972/0x9f0 net/socket.c:2592
___sys_sendmsg+0x2a5/0x360 net/socket.c:2646
__sys_sendmsg net/socket.c:2678 [inline]
__do_sys_sendmsg net/socket.c:2683 [inline]
__se_sys_sendmsg net/socket.c:2681 [inline]
__x64_sys_sendmsg+0x1bd/0x2a0 net/socket.c:2681
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f59d319c819
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f59d4090028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f59d3415fa0 RCX: 00007f59d319c819
RDX: 0000000000000000 RSI: 00002000000002c0 RDI: 000000000000000b
RBP: 00007f59d3232c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f59d3416038 R14: 00007f59d3415fa0 R15: 00007f59d353fa48
----------------
Code disassembly (best guess), 1 bytes skipped:
0: 0f 1f 80 00 00 00 00 nopl 0x0(%rax)
7: 90 nop
8: 90 nop
9: 90 nop
a: 90 nop
b: 90 nop
c: 90 nop
d: 90 nop
e: 90 nop
f: 90 nop
10: 90 nop
11: 90 nop
12: 90 nop
13: 90 nop
14: 90 nop
15: 90 nop
16: 90 nop
17: 0f 1f 40 d6 nopl -0x2a(%rax)
1b: 41 56 push %r14
1d: 53 push %rbx
1e: 48 89 f3 mov %rsi,%rbx
21: 49 89 fe mov %rdi,%r14
24: e8 8e 15 00 00 call 0x15b7
* 29: 84 c0 test %al,%al <-- trapping instruction
2b: 75 16 jne 0x43
2d: be 01 00 00 00 mov $0x1,%esi
32: 4c 89 f7 mov %r14,%rdi
35: 31 d2 xor %edx,%edx
37: 48 89 d9 mov %rbx,%rcx
3a: 89 c3 mov %eax,%ebx
3c: e8 .byte 0xe8
3d: 06 (bad)
3e: 05 .byte 0x5