============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
syz.3.2570/15977 is trying to acquire lock:
ffff8880323dc158 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: spin_lock include/linux/spinlock.h:342 [inline]
ffff8880323dc158 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: __netif_tx_lock include/linux/netdevice.h:4786 [inline]
ffff8880323dc158 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: sch_direct_xmit+0x15f/0x4c0 net/sched/sch_generic.c:370
but task is already holding lock:
ffff888027c14d58 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: spin_lock include/linux/spinlock.h:342 [inline]
ffff888027c14d58 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: __netif_tx_lock include/linux/netdevice.h:4786 [inline]
ffff888027c14d58 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: sch_direct_xmit+0x15f/0x4c0 net/sched/sch_generic.c:370
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(&qdisc_xmit_lock_key#4);
lock(&qdisc_xmit_lock_key#4);
*** DEADLOCK ***
May be due to missing lock nesting notation
13 locks held by syz.3.2570/15977:
#0: ffffc90000a08cc0 ((&ndev->rs_timer)){+.-.}-{0:0}, at: call_timer_fn+0xd4/0x5e0 kernel/time/timer.c:1745
#1: ffffffff8e95cda0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#1: ffffffff8e95cda0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#1: ffffffff8e95cda0 (rcu_read_lock){....}-{1:3}, at: ndisc_send_skb+0x215/0x1670 net/ipv6/ndisc.c:482
#2: ffffffff8e95cda0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#2: ffffffff8e95cda0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#2: ffffffff8e95cda0 (rcu_read_lock){....}-{1:3}, at: ip6_output+0x126/0x550 net/ipv6/ip6_output.c:234
#3: ffffffff8e95ce00 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline]
#3: ffffffff8e95ce00 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:891 [inline]
#3: ffffffff8e95ce00 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x2b6/0x3950 net/core/dev.c:4791
#4: ffffffff8e95cda0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#4: ffffffff8e95cda0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#4: ffffffff8e95cda0 (rcu_read_lock){....}-{1:3}, at: bond_start_xmit+0xb4/0x1900 drivers/net/bonding/bond_main.c:5591
#5: ffffffff8e95ce00 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline]
#5: ffffffff8e95ce00 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:891 [inline]
#5: ffffffff8e95ce00 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x2b6/0x3950 net/core/dev.c:4791
#6: ffff8880583b1228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: spin_trylock include/linux/spinlock.h:354 [inline]
#6: ffff8880583b1228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: qdisc_run_begin include/net/sch_generic.h:205 [inline]
#6: ffff8880583b1228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: __dev_xmit_skb net/core/dev.c:4196 [inline]
#6: ffff8880583b1228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: __dev_queue_xmit+0x11a6/0x3950 net/core/dev.c:4831
#7: ffff888027c14d58 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: spin_lock include/linux/spinlock.h:342 [inline]
#7: ffff888027c14d58 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: __netif_tx_lock include/linux/netdevice.h:4786 [inline]
#7: ffff888027c14d58 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: sch_direct_xmit+0x15f/0x4c0 net/sched/sch_generic.c:370
#8: ffffffff8e95cda0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#8: ffffffff8e95cda0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#8: ffffffff8e95cda0 (rcu_read_lock){....}-{1:3}, at: ip_output+0x5b/0x450 net/ipv4/ip_output.c:433
#9: ffffffff8e95cda0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#9: ffffffff8e95cda0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#9: ffffffff8e95cda0 (rcu_read_lock){....}-{1:3}, at: ip_finish_output2+0x3c2/0x1070 net/ipv4/ip_output.c:230
#10: ffffffff8e95cda0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#10: ffffffff8e95cda0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#10: ffffffff8e95cda0 (rcu_read_lock){....}-{1:3}, at: arp_xmit+0x23/0x270 net/ipv4/arp.c:663
#11: ffffffff8e95ce00 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline]
#11: ffffffff8e95ce00 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:891 [inline]
#11: ffffffff8e95ce00 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x2b6/0x3950 net/core/dev.c:4791
#12: ffff8880795b4228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: spin_trylock include/linux/spinlock.h:354 [inline]
#12: ffff8880795b4228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: qdisc_run_begin include/net/sch_generic.h:205 [inline]
#12: ffff8880795b4228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: __dev_xmit_skb net/core/dev.c:4196 [inline]
#12: ffff8880795b4228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: __dev_queue_xmit+0x11a6/0x3950 net/core/dev.c:4831
stack backtrace:
CPU: 1 UID: 0 PID: 15977 Comm: syz.3.2570 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
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+0x106/0x350 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:158
spin_lock include/linux/spinlock.h:342 [inline]
__netif_tx_lock include/linux/netdevice.h:4786 [inline]
sch_direct_xmit+0x15f/0x4c0 net/sched/sch_generic.c:370
__dev_xmit_skb net/core/dev.c:4209 [inline]
__dev_queue_xmit+0x180f/0x3950 net/core/dev.c:4831
NF_HOOK+0x33a/0x3c0 include/linux/netfilter.h:-1
arp_xmit+0x16c/0x270 net/ipv4/arp.c:665
arp_solicit+0xbe0/0xe40 net/ipv4/arp.c:392
neigh_probe net/core/neighbour.c:1096 [inline]
__neigh_event_send+0xf05/0x14d0 net/core/neighbour.c:1276
neigh_event_send_probe include/net/neighbour.h:480 [inline]
neigh_event_send include/net/neighbour.h:486 [inline]
neigh_resolve_output+0x198/0x750 net/core/neighbour.c:1603
neigh_output include/net/neighbour.h:556 [inline]
ip_finish_output2+0xca9/0x1070 net/ipv4/ip_output.c:237
NF_HOOK_COND include/linux/netfilter.h:307 [inline]
ip_output+0x29f/0x450 net/ipv4/ip_output.c:438
iptunnel_xmit+0x621/0xd10 net/ipv4/ip_tunnel_core.c:97
ip_tunnel_xmit+0x193a/0x1f20 net/ipv4/ip_tunnel.c:845
__gre_xmit+0x19e/0x240 net/ipv4/ip_gre.c:491
erspan_xmit+0xa41/0x14d0 net/ipv4/ip_gre.c:750
__netdev_start_xmit include/linux/netdevice.h:5373 [inline]
netdev_start_xmit include/linux/netdevice.h:5382 [inline]
xmit_one net/core/dev.c:3888 [inline]
dev_hard_start_xmit+0x2cd/0x830 net/core/dev.c:3904
sch_direct_xmit+0x251/0x4c0 net/sched/sch_generic.c:372
__dev_xmit_skb net/core/dev.c:4209 [inline]
__dev_queue_xmit+0x180f/0x3950 net/core/dev.c:4831
__bond_start_xmit drivers/net/bonding/bond_main.c:5571 [inline]
bond_start_xmit+0x766/0x1900 drivers/net/bonding/bond_main.c:5593
__netdev_start_xmit include/linux/netdevice.h:5373 [inline]
netdev_start_xmit include/linux/netdevice.h:5382 [inline]
xmit_one net/core/dev.c:3888 [inline]
dev_hard_start_xmit+0x2cd/0x830 net/core/dev.c:3904
__dev_queue_xmit+0x14d9/0x3950 net/core/dev.c:4870
NF_HOOK_COND include/linux/netfilter.h:307 [inline]
ip6_output+0x340/0x550 net/ipv6/ip6_output.c:246
dst_output include/net/dst.h:470 [inline]
NF_HOOK include/linux/netfilter.h:318 [inline]
ndisc_send_skb+0xd0b/0x1670 net/ipv6/ndisc.c:512
addrconf_rs_timer+0x395/0x6d0 net/ipv6/addrconf.c:4056
call_timer_fn+0x192/0x5e0 kernel/time/timer.c:1748
expire_timers kernel/time/timer.c:1799 [inline]
__run_timers kernel/time/timer.c:2374 [inline]
__run_timer_base+0x652/0x8b0 kernel/time/timer.c:2386
run_timer_base kernel/time/timer.c:2395 [inline]
run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2405
handle_softirqs+0x22a/0x840 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0xca/0x220 kernel/softirq.c:735
irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1061
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:seqcount_lockdep_reader_access+0xec/0x100 include/linux/seqlock.h:76
Code: 00 75 11 e8 66 e2 12 00 4d 85 ff 75 16 e8 5c e2 12 00 eb 15 e8 55 e2 12 00 e8 10 63 f7 09 4d 85 ff 74 ea e8 46 e2 12 00 fb 5b <41> 5e 41 5f c3 cc cc cc cc cc 66 2e 0f 1f 84 00 00 00 00 00 90 90
RSP: 0018:ffffc90004b2fb68 EFLAGS: 00000287
RAX: ffffffff81b2e21a RBX: ffffc90004b2fd90 RCX: 0000000000080000
RDX: ffffc90010946000 RSI: 000000000004cd4a RDI: 000000000004cd4b
RBP: ffffc90004b2fc30 R08: ffffffff90311bf7 R09: 1ffffffff206237e
R10: dffffc0000000000 R11: fffffbfff206237f R12: 1ffff92000965f94
R13: 0000000000000d75 R14: ffffffff81b2f0e9 R15: 0000000000000200
ktime_get_ts64+0xa9/0x410 kernel/time/timekeeping.c:1108
do_recvmmsg+0x400/0x800 net/socket.c:3074
__sys_recvmmsg net/socket.c:3131 [inline]
__do_sys_recvmmsg net/socket.c:3152 [inline]
__se_sys_recvmmsg net/socket.c:3145 [inline]
__x64_sys_recvmmsg+0x1b7/0x250 net/socket.c:3145
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f685f79ce59
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:00007f68606b4028 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00007f685fa16180 RCX: 00007f685f79ce59
RDX: 0400000000000ec0 RSI: 0000200000002ec0 RDI: 000000000000000e
RBP: 00007f685f832d6f R08: 00002000000001c0 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f685fa16218 R14: 00007f685fa16180 R15: 00007ffe6ca74b28
----------------
Code disassembly (best guess):
0: 00 75 11 add %dh,0x11(%rbp)
3: e8 66 e2 12 00 call 0x12e26e
8: 4d 85 ff test %r15,%r15
b: 75 16 jne 0x23
d: e8 5c e2 12 00 call 0x12e26e
12: eb 15 jmp 0x29
14: e8 55 e2 12 00 call 0x12e26e
19: e8 10 63 f7 09 call 0x9f7632e
1e: 4d 85 ff test %r15,%r15
21: 74 ea je 0xd
23: e8 46 e2 12 00 call 0x12e26e
28: fb sti
29: 5b pop %rbx
* 2a: 41 5e pop %r14 <-- trapping instruction
2c: 41 5f pop %r15
2e: c3 ret
2f: cc int3
30: cc int3
31: cc int3
32: cc int3
33: cc int3
34: 66 2e 0f 1f 84 00 00 cs nopw 0x0(%rax,%rax,1)
3b: 00 00 00
3e: 90 nop
3f: 90 nop