============================================
WARNING: possible recursive locking detected
5.15.179-syzkaller #0 Not tainted
--------------------------------------------
kworker/0:3/4169 is trying to acquire lock:
ffff88807987e218 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline]
ffff88807987e218 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3908 [inline]
ffff88807987e218 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_queue_xmit+0x2158/0x32b0 net/core/dev.c:4252
but task is already holding lock:
ffff888079e77258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: spin_trylock include/linux/spinlock.h:373 [inline]
ffff888079e77258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:173 [inline]
ffff888079e77258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3870 [inline]
ffff888079e77258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_queue_xmit+0x1178/0x32b0 net/core/dev.c:4252
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 kworker/0:3/4169:
#0: ffff888017472138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283
#1: ffffc90002ebfd20 ((work_completion)(&(&ssp->work)->work)){+.+.}-{0:0}, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285
#2: ffffc90000007be0 ((&ndev->rs_timer)){+.-.}-{0:0}, at: lockdep_copy_map include/linux/lockdep.h:45 [inline]
#2: ffffc90000007be0 ((&ndev->rs_timer)){+.-.}-{0:0}, at: call_timer_fn+0xbe/0x560 kernel/time/timer.c:1441
#3: ffffffff8cb1f4e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:311
#4: ffffffff8cb1f540 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:312
#5: ffffffff8cb1f540 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:312
#6: ffff888079e77258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: spin_trylock include/linux/spinlock.h:373 [inline]
#6: ffff888079e77258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:173 [inline]
#6: ffff888079e77258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3870 [inline]
#6: ffff888079e77258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_queue_xmit+0x1178/0x32b0 net/core/dev.c:4252
#7: ffffffff8cb1f540 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:312
#8: ffffffff8cb1f540 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:312
stack backtrace:
CPU: 0 PID: 4169 Comm: kworker/0:3 Not tainted 5.15.179-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Workqueue: rcu_gp process_srcu
Call Trace:
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106
print_deadlock_bug kernel/locking/lockdep.c:2946 [inline]
check_deadlock kernel/locking/lockdep.c:2989 [inline]
validate_chain+0x46d2/0x5930 kernel/locking/lockdep.c:3775
__lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012
lock_acquire+0x1db/0x4f0 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:363 [inline]
__dev_xmit_skb net/core/dev.c:3908 [inline]
__dev_queue_xmit+0x2158/0x32b0 net/core/dev.c:4252
neigh_hh_output include/net/neighbour.h:493 [inline]
neigh_output include/net/neighbour.h:507 [inline]
ip_finish_output2+0xcd7/0x11a0 net/ipv4/ip_output.c:228
iptunnel_xmit+0x51a/0x950 net/ipv4/ip_tunnel_core.c:82
ip_tunnel_xmit+0x19c9/0x24f0 net/ipv4/ip_tunnel.c:838
__gre_xmit net/ipv4/ip_gre.c:474 [inline]
gre_tap_xmit+0x4f8/0x6e0 net/ipv4/ip_gre.c:751
__netdev_start_xmit include/linux/netdevice.h:5027 [inline]
netdev_start_xmit include/linux/netdevice.h:5041 [inline]
xmit_one net/core/dev.c:3648 [inline]
dev_hard_start_xmit+0x298/0x7a0 net/core/dev.c:3664
sch_direct_xmit+0x2b2/0x5e0 net/sched/sch_generic.c:342
__dev_xmit_skb net/core/dev.c:3883 [inline]
__dev_queue_xmit+0x1861/0x32b0 net/core/dev.c:4252
neigh_hh_output include/net/neighbour.h:493 [inline]
neigh_output include/net/neighbour.h:507 [inline]
ip6_finish_output2+0xead/0x15a0 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+0xb98/0x1520 net/ipv6/ndisc.c:513
addrconf_rs_timer+0x357/0x610 net/ipv6/addrconf.c:3959
call_timer_fn+0x16d/0x560 kernel/time/timer.c:1451
expire_timers kernel/time/timer.c:1496 [inline]
__run_timers+0x67c/0x890 kernel/time/timer.c:1767
run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1780
handle_softirqs+0x3a7/0x930 kernel/softirq.c:558
__do_softirq kernel/softirq.c:592 [inline]
invoke_softirq kernel/softirq.c:432 [inline]
__irq_exit_rcu+0x157/0x240 kernel/softirq.c:641
irq_exit_rcu+0x5/0x20 kernel/softirq.c:653
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:arch_test_and_set_bit arch/x86/include/asm/bitops.h:138 [inline]
RIP: 0010:test_and_set_bit include/asm-generic/bitops/instrumented-atomic.h:71 [inline]
RIP: 0010:queue_delayed_work_on+0x1fd/0x250 kernel/workqueue.c:1714
Code: 11 e8 37 a1 2d 00 4d 85 e4 75 16 e8 2d a1 2d 00 eb 15 e8 26 a1 2d 00 e8 b1 03 ed 08 4d 85 e4 74 ea e8 17 a1 2d 00 fb 45 84 ff <0f> 94 c0 48 c7 44 24 20 0e 36 e0 45 48 b9 00 00 00 00 00 fc ff df
RSP: 0018:ffffc90002ebfb80 EFLAGS: 00000246
RAX: ffffffff8152fba9 RBX: 0000000000000000 RCX: ffff88802510d940
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90002ebfc50 R08: ffffffff8152fb7f R09: fffffbfff2131e1b
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000200
R13: 1ffff920005d7f74 R14: 0000000000000046 R15: 0000000000000000
process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310
worker_thread+0xaca/0x1280 kernel/workqueue.c:2457
kthread+0x3f6/0x4f0 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
----------------
Code disassembly (best guess), 1 bytes skipped:
0: e8 37 a1 2d 00 call 0x2da13c
5: 4d 85 e4 test %r12,%r12
8: 75 16 jne 0x20
a: e8 2d a1 2d 00 call 0x2da13c
f: eb 15 jmp 0x26
11: e8 26 a1 2d 00 call 0x2da13c
16: e8 b1 03 ed 08 call 0x8ed03cc
1b: 4d 85 e4 test %r12,%r12
1e: 74 ea je 0xa
20: e8 17 a1 2d 00 call 0x2da13c
25: fb sti
26: 45 84 ff test %r15b,%r15b
* 29: 0f 94 c0 sete %al <-- trapping instruction
2c: 48 c7 44 24 20 0e 36 movq $0x45e0360e,0x20(%rsp)
33: e0 45
35: 48 b9 00 00 00 00 00 movabs $0xdffffc0000000000,%rcx
3c: fc ff df