[syzbot] possible deadlock in br_multicast_rcv (2)

From: syzbot
Date: Fri Sep 10 2021 - 03:38:22 EST


Hello,

syzbot found the following issue on:

HEAD commit: 57f780f1c433 atlantic: Fix driver resume flow.
git tree: net
console output: https://syzkaller.appspot.com/x/log.txt?x=13fb836d300000
kernel config: https://syzkaller.appspot.com/x/.config?x=765eea9a273a8879
dashboard link: https://syzkaller.appspot.com/bug?extid=1f749b80a78ec45502f8
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.1

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+1f749b80a78ec45502f8@xxxxxxxxxxxxxxxxxxxxxxxxx

============================================
WARNING: possible recursive locking detected
5.14.0-rc7-syzkaller #0 Not tainted
--------------------------------------------
ksoftirqd/0/13 is trying to acquire lock:
ffff888029d18fd0 (&br->multicast_lock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:354 [inline]
ffff888029d18fd0 (&br->multicast_lock){+.-.}-{2:2}, at: br_ip6_multicast_query net/bridge/br_multicast.c:3000 [inline]
ffff888029d18fd0 (&br->multicast_lock){+.-.}-{2:2}, at: br_multicast_ipv6_rcv net/bridge/br_multicast.c:3393 [inline]
ffff888029d18fd0 (&br->multicast_lock){+.-.}-{2:2}, at: br_multicast_rcv+0x2e31/0x5b90 net/bridge/br_multicast.c:3425

but task is already holding lock:
ffff8880748c4fd0 (&br->multicast_lock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:354 [inline]
ffff8880748c4fd0 (&br->multicast_lock){+.-.}-{2:2}, at: br_multicast_port_query_expired+0x40/0x170 net/bridge/br_multicast.c:1588

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

10 locks held by ksoftirqd/0/13:
#0: ffffc90000d27c58 ((&port->ip6_own_query.timer)){+.-.}-{0:0}, at: lockdep_copy_map include/linux/lockdep.h:35 [inline]
#0: ffffc90000d27c58 ((&port->ip6_own_query.timer)){+.-.}-{0:0}, at: call_timer_fn+0xd5/0x6b0 kernel/time/timer.c:1411
#1: ffff8880748c4fd0 (&br->multicast_lock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:354 [inline]
#1: ffff8880748c4fd0 (&br->multicast_lock){+.-.}-{2:2}, at: br_multicast_port_query_expired+0x40/0x170 net/bridge/br_multicast.c:1588
#2: ffffffff8b97c220 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x1da/0x3620 net/core/dev.c:4219
#3: ffffffff8b97c220 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x1da/0x3620 net/core/dev.c:4219
#4: ffffffff8b97c280 (rcu_read_lock){....}-{1:2}, at: is_netpoll_tx_blocked include/net/bonding.h:109 [inline]
#4: ffffffff8b97c280 (rcu_read_lock){....}-{1:2}, at: bond_start_xmit+0x88/0x1220 drivers/net/bonding/bond_main.c:4878
#5: ffffffff8b97c220 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x1da/0x3620 net/core/dev.c:4219
#6: ffffffff8b97c280 (rcu_read_lock){....}-{1:2}, at: is_netpoll_tx_blocked include/net/bonding.h:109 [inline]
#6: ffffffff8b97c280 (rcu_read_lock){....}-{1:2}, at: bond_start_xmit+0x88/0x1220 drivers/net/bonding/bond_main.c:4878
#7: ffffffff8b97c220 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x1da/0x3620 net/core/dev.c:4219
#8: ffffffff8b97c220 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x1da/0x3620 net/core/dev.c:4219
#9: ffffffff8b97c280 (rcu_read_lock){....}-{1:2}, at: br_dev_xmit+0x0/0x16a0 net/bridge/br_device.c:305

stack backtrace:
CPU: 0 PID: 13 Comm: ksoftirqd/0 Not tainted 5.14.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:105
print_deadlock_bug kernel/locking/lockdep.c:2944 [inline]
check_deadlock kernel/locking/lockdep.c:2987 [inline]
validate_chain kernel/locking/lockdep.c:3776 [inline]
__lock_acquire.cold+0x149/0x3ab kernel/locking/lockdep.c:5015
lock_acquire kernel/locking/lockdep.c:5625 [inline]
lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5590
__raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:151
spin_lock include/linux/spinlock.h:354 [inline]
br_ip6_multicast_query net/bridge/br_multicast.c:3000 [inline]
br_multicast_ipv6_rcv net/bridge/br_multicast.c:3393 [inline]
br_multicast_rcv+0x2e31/0x5b90 net/bridge/br_multicast.c:3425
br_dev_xmit+0x6bf/0x16a0 net/bridge/br_device.c:85
__netdev_start_xmit include/linux/netdevice.h:4948 [inline]
netdev_start_xmit include/linux/netdevice.h:4962 [inline]
xmit_one net/core/dev.c:3659 [inline]
dev_hard_start_xmit+0x1eb/0x920 net/core/dev.c:3675
__dev_queue_xmit+0x2988/0x3620 net/core/dev.c:4285
vlan_dev_hard_start_xmit+0x1b3/0x670 net/8021q/vlan_dev.c:124
__netdev_start_xmit include/linux/netdevice.h:4948 [inline]
netdev_start_xmit include/linux/netdevice.h:4962 [inline]
xmit_one net/core/dev.c:3659 [inline]
dev_hard_start_xmit+0x1eb/0x920 net/core/dev.c:3675
__dev_queue_xmit+0x2988/0x3620 net/core/dev.c:4285
bond_dev_queue_xmit+0xc3/0x170 drivers/net/bonding/bond_main.c:304
bond_do_alb_xmit+0x5ca/0x8b0 drivers/net/bonding/bond_alb.c:1327
__bond_start_xmit drivers/net/bonding/bond_main.c:4859 [inline]
bond_start_xmit+0xaad/0x1220 drivers/net/bonding/bond_main.c:4883
__netdev_start_xmit include/linux/netdevice.h:4948 [inline]
netdev_start_xmit include/linux/netdevice.h:4962 [inline]
xmit_one net/core/dev.c:3659 [inline]
dev_hard_start_xmit+0x1eb/0x920 net/core/dev.c:3675
__dev_queue_xmit+0x2988/0x3620 net/core/dev.c:4285
bond_dev_queue_xmit+0xc3/0x170 drivers/net/bonding/bond_main.c:304
bond_3ad_xor_xmit drivers/net/bonding/bond_main.c:4621 [inline]
__bond_start_xmit drivers/net/bonding/bond_main.c:4855 [inline]
bond_start_xmit+0xb01/0x1220 drivers/net/bonding/bond_main.c:4883
__netdev_start_xmit include/linux/netdevice.h:4948 [inline]
netdev_start_xmit include/linux/netdevice.h:4962 [inline]
xmit_one net/core/dev.c:3659 [inline]
dev_hard_start_xmit+0x1eb/0x920 net/core/dev.c:3675
__dev_queue_xmit+0x2988/0x3620 net/core/dev.c:4285
macvlan_queue_xmit drivers/net/macvlan.c:543 [inline]
macvlan_start_xmit+0x156/0x5e0 drivers/net/macvlan.c:567
__netdev_start_xmit include/linux/netdevice.h:4948 [inline]
netdev_start_xmit include/linux/netdevice.h:4962 [inline]
xmit_one net/core/dev.c:3659 [inline]
dev_hard_start_xmit+0x1eb/0x920 net/core/dev.c:3675
__dev_queue_xmit+0x2988/0x3620 net/core/dev.c:4285
br_dev_queue_push_xmit+0x252/0x730 net/bridge/br_forward.c:51
NF_HOOK include/linux/netfilter.h:307 [inline]
__br_multicast_send_query+0xf7e/0x39f0 net/bridge/br_multicast.c:1527
br_multicast_send_query+0x27c/0x420 net/bridge/br_multicast.c:1572
br_multicast_port_query_expired+0x118/0x170 net/bridge/br_multicast.c:1596
call_timer_fn+0x1a5/0x6b0 kernel/time/timer.c:1421
expire_timers kernel/time/timer.c:1466 [inline]
__run_timers.part.0+0x675/0xa20 kernel/time/timer.c:1734
__run_timers kernel/time/timer.c:1715 [inline]
run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1747
__do_softirq+0x29b/0x9c2 kernel/softirq.c:558
run_ksoftirqd kernel/softirq.c:920 [inline]
run_ksoftirqd+0x2d/0x60 kernel/softirq.c:912
smpboot_thread_fn+0x645/0x9c0 kernel/smpboot.c:164
kthread+0x3e5/0x4d0 kernel/kthread.c:319
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
bridge0: received packet on veth1_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth1_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth1_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth1_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth1_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth1_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)


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