============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
syz-executor/4187 is trying to acquire lock:
ffff888024514a18 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:364 [inline]
ffff888024514a18 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3909 [inline]
ffff888024514a18 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_queue_xmit+0x1ffc/0x2fd0 net/core/dev.c:4253
but task is already holding lock:
ffff8880607fc258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: spin_trylock include/linux/spinlock.h:374 [inline]
ffff8880607fc258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:173 [inline]
ffff8880607fc258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3871 [inline]
ffff8880607fc258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_queue_xmit+0x1120/0x2fd0 net/core/dev.c:4253
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
9 locks held by syz-executor/4187:
#0: ffffc90000007be0 ((&ndev->rs_timer)){+.-.}-{0:0}, at: lockdep_copy_map include/linux/lockdep.h:45 [inline]
#0: ffffc90000007be0 ((&ndev->rs_timer)){+.-.}-{0:0}, at: call_timer_fn+0xca/0x540 kernel/time/timer.c:1441
#1: ffffffff8c31c720 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:312
#2: ffffffff8c31c780 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:313
#3: ffffffff8c31c780 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:313
#4: ffffffff8c31c720 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:312
#5: ffffffff8c31c780 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:313
#6: ffff8880607fc258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: spin_trylock include/linux/spinlock.h:374 [inline]
#6: ffff8880607fc258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:173 [inline]
#6: ffff8880607fc258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3871 [inline]
#6: ffff8880607fc258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_queue_xmit+0x1120/0x2fd0 net/core/dev.c:4253
#7: ffffffff8c31c780 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:313
#8: ffffffff8c31c780 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:313
stack backtrace:
CPU: 0 PID: 4187 Comm: syz-executor Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
__lock_acquire+0x1236/0x7d10 kernel/locking/lockdep.c:-1
lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623
__raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154
spin_lock include/linux/spinlock.h:364 [inline]
__dev_xmit_skb net/core/dev.c:3909 [inline]
__dev_queue_xmit+0x1ffc/0x2fd0 net/core/dev.c:4253
neigh_hh_output include/net/neighbour.h:493 [inline]
neigh_output include/net/neighbour.h:507 [inline]
ip_finish_output2+0xc87/0x10a0 net/ipv4/ip_output.c:228
iptunnel_xmit+0x4d6/0x8e0 net/ipv4/ip_tunnel_core.c:82
ip_tunnel_xmit+0x1905/0x2280 net/ipv4/ip_tunnel.c:824
__gre_xmit net/ipv4/ip_gre.c:474 [inline]
gre_tap_xmit+0x4f9/0x6e0 net/ipv4/ip_gre.c:751
__netdev_start_xmit include/linux/netdevice.h:5036 [inline]
netdev_start_xmit include/linux/netdevice.h:5050 [inline]
xmit_one net/core/dev.c:3649 [inline]
dev_hard_start_xmit+0x2a5/0x7e0 net/core/dev.c:3665
sch_direct_xmit+0x25a/0x4b0 net/sched/sch_generic.c:345
__dev_xmit_skb net/core/dev.c:3884 [inline]
__dev_queue_xmit+0x179f/0x2fd0 net/core/dev.c:4253
bond_dev_queue_xmit+0x112/0x1e0 drivers/net/bonding/bond_main.c:304
__bond_start_xmit drivers/net/bonding/bond_main.c:5138 [inline]
bond_start_xmit+0xdb5/0x1ad0 drivers/net/bonding/bond_main.c:5160
__netdev_start_xmit include/linux/netdevice.h:5036 [inline]
netdev_start_xmit include/linux/netdevice.h:5050 [inline]
xmit_one net/core/dev.c:3649 [inline]
dev_hard_start_xmit+0x2a5/0x7e0 net/core/dev.c:3665
__dev_queue_xmit+0x1a78/0x2fd0 net/core/dev.c:4288
neigh_hh_output include/net/neighbour.h:493 [inline]
neigh_output include/net/neighbour.h:507 [inline]
ip6_finish_output2+0x1051/0x1510 net/ipv6/ip6_output.c:130
dst_output include/net/dst.h:452 [inline]
NF_HOOK include/linux/netfilter.h:302 [inline]
ndisc_send_skb+0xc2a/0x1500 net/ipv6/ndisc.c:513
addrconf_rs_timer+0x2d1/0x630 net/ipv6/addrconf.c:3956
call_timer_fn+0x17b/0x540 kernel/time/timer.c:1451
expire_timers kernel/time/timer.c:1496 [inline]
__run_timers+0x53a/0x7f0 kernel/time/timer.c:1767
run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1780
handle_softirqs+0x339/0x830 kernel/softirq.c:576
__do_softirq kernel/softirq.c:610 [inline]
invoke_softirq kernel/softirq.c:450 [inline]
__irq_exit_rcu+0x13b/0x230 kernel/softirq.c:659
irq_exit_rcu+0x5/0x20 kernel/softirq.c:671
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:path_init+0x0/0x1160 fs/namei.c:2333
Code: 5d 41 5e 41 5f 5d c3 e8 5e b3 ac ff 41 bd fe ff ff ff eb ce 44 89 f1 80 e1 07 38 c1 7c d4 4c 89 f7 e8 74 b7 f1 ff eb ca 66 90 <55> 41 57 41 56 41 55 41 54 53 48 83 ec 70 41 89 f5 49 89 fe 49 bc
RSP: 0018:ffffc90002edfb58 EFLAGS: 00000202
RAX: ffffffff81cb45ff RBX: ffffc90002edfbe0 RCX: ffff88807a501dc0
RDX: 0000000000000000 RSI: 0000000000000040 RDI: ffffc90002edfbe0
RBP: ffffc90002edfd48 R08: ffffc90002edfbef R09: ffffc90002edfbe0
R10: dffffc0000000000 R11: fffff520005dbf7e R12: 0000000000000000
R13: 1ffff920005dbf78 R14: ffff88807a502690 R15: 0000000000000000
path_parentat fs/namei.c:2509 [inline]
__filename_parentat+0x247/0x690 fs/namei.c:2534
filename_parentat fs/namei.c:2552 [inline]
filename_create+0xd5/0x470 fs/namei.c:3824
do_mkdirat+0xa5/0x5b0 fs/namei.c:4088
__do_sys_mkdirat fs/namei.c:4113 [inline]
__se_sys_mkdirat fs/namei.c:4111 [inline]
__x64_sys_mkdirat+0x85/0x90 fs/namei.c:4111
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f3e83d67b97
Code: 00 66 90 48 89 f2 b9 00 01 00 00 48 89 fe bf 9c ff ff ff e9 db f7 ff ff 66 2e 0f 1f 84 00 00 00 00 00 90 b8 02 01 00 00 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:00007ffe83eb2578 EFLAGS: 00000206 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007ffe83eb25d0 RCX: 00007f3e83d67b97
RDX: 00000000000001ff RSI: 00007ffe83eb25d0 RDI: 00000000ffffff9c
RBP: 00007ffe83eb25bc R08: 0000000000000002 R09: 00000000fffffffe
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000054
R13: 00000000000927c0 R14: 000000000002a6bf R15: 00007ffe83eb2610
----------------
Code disassembly (best guess):
0: 5d pop %rbp
1: 41 5e pop %r14
3: 41 5f pop %r15
5: 5d pop %rbp
6: c3 ret
7: e8 5e b3 ac ff call 0xffacb36a
c: 41 bd fe ff ff ff mov $0xfffffffe,%r13d
12: eb ce jmp 0xffffffe2
14: 44 89 f1 mov %r14d,%ecx
17: 80 e1 07 and $0x7,%cl
1a: 38 c1 cmp %al,%cl
1c: 7c d4 jl 0xfffffff2
1e: 4c 89 f7 mov %r14,%rdi
21: e8 74 b7 f1 ff call 0xfff1b79a
26: eb ca jmp 0xfffffff2
28: 66 90 xchg %ax,%ax
* 2a: 55 push %rbp <-- trapping instruction
2b: 41 57 push %r15
2d: 41 56 push %r14
2f: 41 55 push %r13
31: 41 54 push %r12
33: 53 push %rbx
34: 48 83 ec 70 sub $0x70,%rsp
38: 41 89 f5 mov %esi,%r13d
3b: 49 89 fe mov %rdi,%r14
3e: 49 rex.WB
3f: bc .byte 0xbc