============================================
WARNING: possible recursive locking detected
6.1.147-syzkaller #0 Not tainted
--------------------------------------------
syz-executor/4270 is trying to acquire lock:
ffff88805ab8fa18 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline]
ffff88805ab8fa18 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3925 [inline]
ffff88805ab8fa18 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_queue_xmit+0x208f/0x3760 net/core/dev.c:4300
but task is already holding lock:
ffff888055828258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: spin_trylock include/linux/spinlock.h:361 [inline]
ffff888055828258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:195 [inline]
ffff888055828258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3882 [inline]
ffff888055828258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_queue_xmit+0x129a/0x3760 net/core/dev.c:4300
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(dev->qdisc_tx_busylock ?: &qdisc_tx_busylock);
lock(dev->qdisc_tx_busylock ?: &qdisc_tx_busylock);
*** DEADLOCK ***
May be due to missing lock nesting notation
10 locks held by syz-executor/4270:
#0: ffffffff8cb2ae20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
#0: ffffffff8cb2ae20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
#0: ffffffff8cb2ae20 (rcu_read_lock){....}-{1:2}, at: net_generic+0x1e/0x240 include/net/netns/generic.h:45
#1: ffffc90000007bc0 ((&ndev->rs_timer)){+.-.}-{0:0}, at: call_timer_fn+0xc1/0x670 kernel/time/timer.c:1501
#2: ffffffff8cb2ae20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
#2: ffffffff8cb2ae20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
#2: ffffffff8cb2ae20 (rcu_read_lock){....}-{1:2}, at: ndisc_send_skb+0x1f2/0x1510 net/ipv6/ndisc.c:484
#3: ffffffff8cb2ae20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
#3: ffffffff8cb2ae20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
#3: ffffffff8cb2ae20 (rcu_read_lock){....}-{1:2}, at: ip6_finish_output2+0x593/0x1590 net/ipv6/ip6_output.c:123
#4: ffffffff8cb2ae80 (rcu_read_lock_bh){....}-{1:2}, at: local_bh_disable include/linux/bottom_half.h:20 [inline]
#4: ffffffff8cb2ae80 (rcu_read_lock_bh){....}-{1:2}, at: rcu_read_lock_bh include/linux/rcupdate.h:843 [inline]
#4: ffffffff8cb2ae80 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x26f/0x3760 net/core/dev.c:4257
#5: ffffffff8cb2ae20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
#5: ffffffff8cb2ae20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
#5: ffffffff8cb2ae20 (rcu_read_lock){....}-{1:2}, at: bond_start_xmit+0xfe/0x1b90 drivers/net/bonding/bond_main.c:5523
#6: ffffffff8cb2ae80 (rcu_read_lock_bh){....}-{1:2}, at: local_bh_disable include/linux/bottom_half.h:20 [inline]
#6: ffffffff8cb2ae80 (rcu_read_lock_bh){....}-{1:2}, at: rcu_read_lock_bh include/linux/rcupdate.h:843 [inline]
#6: ffffffff8cb2ae80 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x26f/0x3760 net/core/dev.c:4257
#7: ffff888055828258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: spin_trylock include/linux/spinlock.h:361 [inline]
#7: ffff888055828258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:195 [inline]
#7: ffff888055828258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3882 [inline]
#7: ffff888055828258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_queue_xmit+0x129a/0x3760 net/core/dev.c:4300
#8: ffffffff8cb2ae20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
#8: ffffffff8cb2ae20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
#8: ffffffff8cb2ae20 (rcu_read_lock){....}-{1:2}, at: ip_finish_output2+0x3e8/0x11b0 net/ipv4/ip_output.c:221
#9: ffffffff8cb2ae80 (rcu_read_lock_bh){....}-{1:2}, at: local_bh_disable include/linux/bottom_half.h:20 [inline]
#9: ffffffff8cb2ae80 (rcu_read_lock_bh){....}-{1:2}, at: rcu_read_lock_bh include/linux/rcupdate.h:843 [inline]
#9: ffffffff8cb2ae80 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0x26f/0x3760 net/core/dev.c:4257
stack backtrace:
CPU: 0 PID: 4270 Comm: syz-executor Not tainted 6.1.147-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106
__lock_acquire+0x122f/0x7c50 kernel/locking/lockdep.c:-1
lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662
__raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
_raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154
spin_lock include/linux/spinlock.h:351 [inline]
__dev_xmit_skb net/core/dev.c:3925 [inline]
__dev_queue_xmit+0x208f/0x3760 net/core/dev.c:4300
dev_queue_xmit include/linux/netdevice.h:3051 [inline]
neigh_hh_output include/net/neighbour.h:528 [inline]
neigh_output include/net/neighbour.h:542 [inline]
ip_finish_output2+0xbe8/0x11b0 net/ipv4/ip_output.c:228
iptunnel_xmit+0x525/0x930 net/ipv4/ip_tunnel_core.c:82
ip_tunnel_xmit+0x1c39/0x2360 net/ipv4/ip_tunnel.c:858
__gre_xmit net/ipv4/ip_gre.c:474 [inline]
gre_tap_xmit+0x50b/0x700 net/ipv4/ip_gre.c:751
__netdev_start_xmit include/linux/netdevice.h:4896 [inline]
netdev_start_xmit include/linux/netdevice.h:4910 [inline]
xmit_one net/core/dev.c:3658 [inline]
dev_hard_start_xmit+0x262/0x870 net/core/dev.c:3674
sch_direct_xmit+0x24e/0x4a0 net/sched/sch_generic.c:342
__dev_xmit_skb net/core/dev.c:3895 [inline]
__dev_queue_xmit+0x18cd/0x3760 net/core/dev.c:4300
dev_queue_xmit include/linux/netdevice.h:3051 [inline]
bond_dev_queue_xmit+0x108/0x1e0 drivers/net/bonding/bond_main.c:307
__bond_start_xmit drivers/net/bonding/bond_main.c:5503 [inline]
bond_start_xmit+0xced/0x1b90 drivers/net/bonding/bond_main.c:5525
__netdev_start_xmit include/linux/netdevice.h:4896 [inline]
netdev_start_xmit include/linux/netdevice.h:4910 [inline]
xmit_one net/core/dev.c:3658 [inline]
dev_hard_start_xmit+0x262/0x870 net/core/dev.c:3674
__dev_queue_xmit+0x1bf1/0x3760 net/core/dev.c:4334
neigh_output include/net/neighbour.h:544 [inline]
ip6_finish_output2+0xda2/0x1590 net/ipv6/ip6_output.c:138
dst_output include/net/dst.h:453 [inline]
NF_HOOK include/linux/netfilter.h:302 [inline]
ndisc_send_skb+0xbfb/0x1510 net/ipv6/ndisc.c:513
addrconf_rs_timer+0x2b8/0x600 net/ipv6/addrconf.c:3980
call_timer_fn+0x1a0/0x670 kernel/time/timer.c:1504
expire_timers kernel/time/timer.c:1549 [inline]
__run_timers+0x525/0x7c0 kernel/time/timer.c:1820
run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1833
handle_softirqs+0x2a1/0x920 kernel/softirq.c:596
__do_softirq kernel/softirq.c:630 [inline]
invoke_softirq kernel/softirq.c:470 [inline]
__irq_exit_rcu+0x12f/0x220 kernel/softirq.c:679
irq_exit_rcu+0x5/0x20 kernel/softirq.c:691
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:rcu_read_lock_held_common kernel/rcu/update.c:112 [inline]
RIP: 0010:rcu_read_lock_held+0x15/0x40 kernel/rcu/update.c:309
Code: 00 00 00 00 00 e8 9b 3b 01 00 e9 16 3f 01 00 66 0f 1f 44 00 00 53 e8 fa 2b ac 08 85 c0 74 26 31 db e8 ff 09 01 00 84 c0 74 20 56 0b 01 00 84 c0 74 17 48 c7 c7 20 ae b2 8c be ff ff ff ff 5b
RSP: 0018:ffffc900040479a8 EFLAGS: 00000202
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 394bd40669c2b700
RDX: ffff88801a38d940 RSI: ffffffff8adef300 RDI: ffffffff8adef2c0
RBP: 0000000000000034 R08: dffffc0000000000 R09: fffffbfff215ba49
R10: fffffbfff215ba49 R11: 1ffffffff215ba48 R12: ffff88805aed1800
R13: dffffc0000000000 R14: 0000000000000001 R15: dffffc0000000000
net_generic+0x101/0x240 include/net/netns/generic.h:46
xt_find_table_lock+0x38/0x360 net/netfilter/x_tables.c:1237
get_entries net/ipv6/netfilter/ip6_tables.c:1037 [inline]
do_ip6t_get_ctl+0x6ca/0x1100 net/ipv6/netfilter/ip6_tables.c:1679
nf_getsockopt+0x25e/0x280 net/netfilter/nf_sockopt.c:116
ipv6_getsockopt+0x212/0x2c0 net/ipv6/ipv6_sockglue.c:1512
__sys_getsockopt+0x1b0/0x230 net/socket.c:2332
__do_sys_getsockopt net/socket.c:2347 [inline]
__se_sys_getsockopt net/socket.c:2344 [inline]
__x64_sys_getsockopt+0xb1/0xc0 net/socket.c:2344
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f967279092a
Code: ff c3 66 0f 1f 44 00 00 48 c7 c2 a8 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff eb b8 0f 1f 44 00 00 49 89 ca b8 37 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 06 c3 0f 1f 44 00 00 48 c7 c2 a8 ff ff ff f7
RSP: 002b:00007ffd98bf2448 EFLAGS: 00000212 ORIG_RAX: 0000000000000037
RAX: ffffffffffffffda RBX: 00007ffd98bf24d0 RCX: 00007f967279092a
RDX: 0000000000000041 RSI: 0000000000000029 RDI: 0000000000000003
RBP: 0000000000000003 R08: 00007ffd98bf246c R09: 0079746972756365
R10: 00007ffd98bf24d0 R11: 0000000000000212 R12: 00007f9672983a20
R13: 00007ffd98bf246c R14: 0000000000000000 R15: 00007f9672984e60
GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog
GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog
GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog
----------------
Code disassembly (best guess), 1 bytes skipped:
0: 00 00 add %al,(%rax)
2: 00 00 add %al,(%rax)
4: e8 9b 3b 01 00 call 0x13ba4
9: e9 16 3f 01 00 jmp 0x13f24
e: 66 0f 1f 44 00 00 nopw 0x0(%rax,%rax,1)
14: 53 push %rbx
15: e8 fa 2b ac 08 call 0x8ac2c14
1a: 85 c0 test %eax,%eax
1c: 74 26 je 0x44
1e: 31 db xor %ebx,%ebx
20: e8 ff 09 01 00 call 0x10a24
25: 84 c0 test %al,%al
27: 74 20 je 0x49
* 29: e8 56 0b 01 00 call 0x10b84 <-- trapping instruction
2e: 84 c0 test %al,%al
30: 74 17 je 0x49
32: 48 c7 c7 20 ae b2 8c mov $0xffffffff8cb2ae20,%rdi
39: be ff ff ff ff mov $0xffffffff,%esi
3e: 5b pop %rbx