============================================
WARNING: possible recursive locking detected
6.8.0-syzkaller-08073-g480e035fc4c7 #0 Not tainted
--------------------------------------------
syz-executor.3/6078 is trying to acquire lock:
ffff88803e3013e0 (&br->multicast_lock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline]
ffff88803e3013e0 (&br->multicast_lock){+.-.}-{2:2}, at: br_ip6_multicast_query net/bridge/br_multicast.c:3523 [inline]
ffff88803e3013e0 (&br->multicast_lock){+.-.}-{2:2}, at: br_multicast_ipv6_rcv net/bridge/br_multicast.c:3919 [inline]
ffff88803e3013e0 (&br->multicast_lock){+.-.}-{2:2}, at: br_multicast_rcv+0x30e2/0x8180 net/bridge/br_multicast.c:3974
but task is already holding lock:
ffff8880385d93e0 (&br->multicast_lock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline]
ffff8880385d93e0 (&br->multicast_lock){+.-.}-{2:2}, at: br_multicast_port_query_expired+0x64/0x3b0 net/bridge/br_multicast.c:1905
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
5 locks held by syz-executor.3/6078:
#0: ffffc90000a08c00 ((&pmctx->ip6_own_query.timer)){+.-.}-{0:0}, at: call_timer_fn+0xc0/0x600 kernel/time/timer.c:1789
#1: ffff8880385d93e0 (&br->multicast_lock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline]
#1: ffff8880385d93e0 (&br->multicast_lock){+.-.}-{2:2}, at: br_multicast_port_query_expired+0x64/0x3b0 net/bridge/br_multicast.c:1905
#2: ffffffff8e132080 (rcu_read_lock_bh){....}-{1:2}, at: local_bh_disable include/linux/bottom_half.h:20 [inline]
#2: ffffffff8e132080 (rcu_read_lock_bh){....}-{1:2}, at: rcu_read_lock_bh include/linux/rcupdate.h:802 [inline]
#2: ffffffff8e132080 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x2c4/0x3b10 net/core/dev.c:4260
#3: ffffffff8e132080 (rcu_read_lock_bh){....}-{1:2}, at: local_bh_disable include/linux/bottom_half.h:20 [inline]
#3: ffffffff8e132080 (rcu_read_lock_bh){....}-{1:2}, at: rcu_read_lock_bh include/linux/rcupdate.h:802 [inline]
#3: ffffffff8e132080 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x2c4/0x3b10 net/core/dev.c:4260
#4: ffffffff8e132020 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:298 [inline]
#4: ffffffff8e132020 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:750 [inline]
#4: ffffffff8e132020 (rcu_read_lock){....}-{1:2}, at: br_dev_xmit+0x1b9/0x1a10 net/bridge/br_device.c:44
stack backtrace:
CPU: 1 PID: 6078 Comm: syz-executor.3 Not tainted 6.8.0-syzkaller-08073-g480e035fc4c7 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
check_deadlock kernel/locking/lockdep.c:3062 [inline]
validate_chain+0x15c1/0x58e0 kernel/locking/lockdep.c:3856
__lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137
lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754
__raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
_raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
spin_lock include/linux/spinlock.h:351 [inline]
br_ip6_multicast_query net/bridge/br_multicast.c:3523 [inline]
br_multicast_ipv6_rcv net/bridge/br_multicast.c:3919 [inline]
br_multicast_rcv+0x30e2/0x8180 net/bridge/br_multicast.c:3974
br_dev_xmit+0xb17/0x1a10 net/bridge/br_device.c:90
__netdev_start_xmit include/linux/netdevice.h:4903 [inline]
netdev_start_xmit include/linux/netdevice.h:4917 [inline]
xmit_one net/core/dev.c:3531 [inline]
dev_hard_start_xmit+0x26a/0x790 net/core/dev.c:3547
__dev_queue_xmit+0x19f4/0x3b10 net/core/dev.c:4335
dev_queue_xmit include/linux/netdevice.h:3091 [inline]
vlan_dev_hard_start_xmit+0x36c/0x5f0 net/8021q/vlan_dev.c:125
__netdev_start_xmit include/linux/netdevice.h:4903 [inline]
netdev_start_xmit include/linux/netdevice.h:4917 [inline]
xmit_one net/core/dev.c:3531 [inline]
dev_hard_start_xmit+0x26a/0x790 net/core/dev.c:3547
__dev_queue_xmit+0x19f4/0x3b10 net/core/dev.c:4335
dev_queue_xmit include/linux/netdevice.h:3091 [inline]
br_dev_queue_push_xmit+0x701/0x8d0 net/bridge/br_forward.c:53
NF_HOOK include/linux/netfilter.h:314 [inline]
__br_multicast_send_query+0x2ecb/0x4750 net/bridge/br_multicast.c:1809
br_multicast_send_query+0x4ee/0x6b0 net/bridge/br_multicast.c:1888
br_multicast_port_query_expired+0x2d4/0x3b0 net/bridge/br_multicast.c:1913
call_timer_fn+0x17e/0x600 kernel/time/timer.c:1792
expire_timers kernel/time/timer.c:1843 [inline]
__run_timers kernel/time/timer.c:2408 [inline]
__run_timer_base+0x66a/0x8e0 kernel/time/timer.c:2419
run_timer_base kernel/time/timer.c:2428 [inline]
run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2438
__do_softirq+0x2bc/0x943 kernel/softirq.c:554
invoke_softirq kernel/softirq.c:428 [inline]
__irq_exit_rcu+0xf2/0x1c0 kernel/softirq.c:633
irq_exit_rcu+0x9/0x30 kernel/softirq.c:645
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1043
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:audit_dummy_context include/linux/audit.h:322 [inline]
RIP: 0010:audit_getname include/linux/audit.h:368 [inline]
RIP: 0010:getname_flags+0x1c6/0x4f0 fs/namei.c:203
Code: e8 03 80 3c 18 00 74 08 48 89 ef e8 04 1c ec ff 48 c7 45 00 00 00 00 00 41 80 3c 1f 00 74 08 4c 89 f7 e8 fd 1a ec ff 49 8b 2e <48> 85 ed 74 2e 48 89 e8 48 c1 e8 03 0f b6 04 18 84 c0 0f 85 0c 02
RSP: 0018:ffffc9000314fdd8 EFLAGS: 00000246
RAX: 1ffff1100f915883 RBX: dffffc0000000000 RCX: ffff88802a0ada00
RDX: 0000000000000000 RSI: 000000000000000e RDI: ffff88807c8ac408
RBP: 0000000000000000 R08: ffffffff820c2917 R09: 1ffff1100f915882
R10: dffffc0000000000 R11: ffffed100f915883 R12: ffff88807c8ac410
R13: ffff88807c8ac400 R14: ffff88802a0ae368 R15: 1ffff11005415c6d
user_path_at_empty+0x2c/0x60 fs/namei.c:2920
user_path_at include/linux/namei.h:57 [inline]
ksys_umount fs/namespace.c:1916 [inline]
__do_sys_umount fs/namespace.c:1924 [inline]
__se_sys_umount fs/namespace.c:1922 [inline]
__x64_sys_umount+0xf4/0x170 fs/namespace.c:1922
do_syscall_64+0xfb/0x240
entry_SYSCALL_64_after_hwframe+0x6d/0x75
RIP: 0033:0x7f047387f0d7
Code: b0 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 0f 1f 44 00 00 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 b0 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007f0473acec68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f047387f0d7
RDX: 0000000000000000 RSI: 000000000000000a RDI: 00007f0473aced20
RBP: 00007f0473aced20 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007f0473acfde0
R13: 00007f04738c93b9 R14: 000000000004a47e R15: 0000000000000004
</TASK>
----------------
Code disassembly (best guess):
0: e8 03 80 3c 18 call 0x183c8008
5: 00 74 08 48 add %dh,0x48(%rax,%rcx,1)
9: 89 ef mov %ebp,%edi
b: e8 04 1c ec ff call 0xffec1c14
10: 48 c7 45 00 00 00 00 movq $0x0,0x0(%rbp)
17: 00
18: 41 80 3c 1f 00 cmpb $0x0,(%r15,%rbx,1)
1d: 74 08 je 0x27
1f: 4c 89 f7 mov %r14,%rdi
22: e8 fd 1a ec ff call 0xffec1b24
27: 49 8b 2e mov (%r14),%rbp
* 2a: 48 85 ed test %rbp,%rbp <-- trapping instruction
2d: 74 2e je 0x5d
2f: 48 89 e8 mov %rbp,%rax
32: 48 c1 e8 03 shr $0x3,%rax
36: 0f b6 04 18 movzbl (%rax,%rbx,1),%eax
3a: 84 c0 test %al,%al
3c: 0f .byte 0xf
3d: 85 0c 02 test %ecx,(%rdx,%rax,1)