============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
udevd/3560 is trying to acquire lock:
ffff88801bad9218 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:364 [inline]
ffff88801bad9218 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3909 [inline]
ffff88801bad9218 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_queue_xmit+0x1f6e/0x2ed0 net/core/dev.c:4253
but task is already holding lock:
ffff888075d6a258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: spin_trylock include/linux/spinlock.h:374 [inline]
ffff888075d6a258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:173 [inline]
ffff888075d6a258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3871 [inline]
ffff888075d6a258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_queue_xmit+0x10b9/0x2ed0 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
10 locks held by udevd/3560:
#0: ffff88807f190460 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x28a/0xd00 fs/read_write.c:590
#1: ffffc90000dd0be0 ((&ndev->rs_timer)){+.-.}-{0:0}, at: lockdep_copy_map include/linux/lockdep.h:45 [inline]
#1: ffffc90000dd0be0 ((&ndev->rs_timer)){+.-.}-{0:0}, at: call_timer_fn+0xbb/0x530 kernel/time/timer.c:1441
#2: ffffffff8c11c760 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:312
#3: ffffffff8c11c7c0 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:313
#4: ffffffff8c11c7c0 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:313
#5: ffffffff8c11c760 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:312
#6: ffffffff8c11c7c0 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:313
#7: ffff888075d6a258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: spin_trylock include/linux/spinlock.h:374 [inline]
#7: ffff888075d6a258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:173 [inline]
#7: ffff888075d6a258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3871 [inline]
#7: ffff888075d6a258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_queue_xmit+0x10b9/0x2ed0 net/core/dev.c:4253
#8: ffffffff8c11c7c0 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:313
#9: ffffffff8c11c7c0 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:313
stack backtrace:
CPU: 1 PID: 3560 Comm: udevd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
__lock_acquire+0x1227/0x7c60 kernel/locking/lockdep.c:-1
lock_acquire+0x197/0x3f0 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+0x1f6e/0x2ed0 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+0xc69/0x1080 net/ipv4/ip_output.c:228
iptunnel_xmit+0x525/0x960 net/ipv4/ip_tunnel_core.c:82
ip_tunnel_xmit+0x1b6f/0x2240 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+0x24e/0x4a0 net/sched/sch_generic.c:342
__dev_xmit_skb net/core/dev.c:3884 [inline]
__dev_queue_xmit+0x170e/0x2ed0 net/core/dev.c:4253
bond_dev_queue_xmit+0x106/0x1e0 drivers/net/bonding/bond_main.c:304
__bond_start_xmit drivers/net/bonding/bond_main.c:5138 [inline]
bond_start_xmit+0xd69/0x1a70 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+0x19df/0x2ed0 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+0x1035/0x1500 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+0xbea/0x14a0 net/ipv6/ndisc.c:513
addrconf_rs_timer+0x2b8/0x600 net/ipv6/addrconf.c:3956
call_timer_fn+0x16c/0x530 kernel/time/timer.c:1451
expire_timers kernel/time/timer.c:1496 [inline]
__run_timers+0x525/0x7c0 kernel/time/timer.c:1767
run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1780
handle_softirqs+0x328/0x820 kernel/softirq.c:576
__do_softirq kernel/softirq.c:610 [inline]
invoke_softirq kernel/softirq.c:450 [inline]
__irq_exit_rcu+0x12f/0x220 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:preempt_count arch/x86/include/asm/preempt.h:27 [inline]
RIP: 0010:preempt_latency_start kernel/sched/core.c:5489 [inline]
RIP: 0010:preempt_count_add+0x70/0x190 kernel/sched/core.c:5515
Code: c1 e8 03 42 0f b6 04 38 84 c0 0f 85 e6 00 00 00 83 3d 83 de ba 14 00 75 11 65 8b 05 c2 fe b0 7e 0f b6 c0 3d f5 00 00 00 73 58 <65> 8b 05 b1 fe b0 7e 25 ff ff ff 7f 39 f8 75 42 48 8b 5c 24 18 48
RSP: 0018:ffffc90002e0f828 EFLAGS: 00000297
RAX: 0000000000000001 RBX: ffffc90002e0f908 RCX: ffffffff960c4f03
RDX: dffffc0000000000 RSI: ffffffff89c000ca RDI: 0000000000000001
RBP: ffffc90002e0f950 R08: ffffc90002e0f9d0 R09: 0000000000000005
R10: fffff520005c1f2d R11: 1ffff920005c1f2b R12: ffffffff89c000ca
R13: ffffc90002e0ff58 R14: dffffc0000000000 R15: dffffc0000000000
unwind_next_frame+0xac/0x1d90 arch/x86/kernel/unwind_orc.c:433
arch_stack_walk+0x10c/0x140 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x98/0xe0 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:38 [inline]
kasan_set_track mm/kasan/common.c:46 [inline]
set_alloc_info mm/kasan/common.c:434 [inline]
____kasan_kmalloc mm/kasan/common.c:513 [inline]
__kasan_kmalloc+0xb5/0xf0 mm/kasan/common.c:522
kmalloc include/linux/slab.h:612 [inline]
kernfs_fop_write_iter+0x155/0x4c0 fs/kernfs/file.c:273
call_write_iter include/linux/fs.h:2173 [inline]
new_sync_write fs/read_write.c:507 [inline]
vfs_write+0x712/0xd00 fs/read_write.c:594
ksys_write+0x14d/0x250 fs/read_write.c:647
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: 0033:0x7f2129cb0407
Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007ffc34f70870 EFLAGS: 00000202 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f2129bc2880 RCX: 00007f2129cb0407
RDX: 0000000000000007 RSI: 0000564cf2075f20 RDI: 000000000000000c
RBP: 0000564cf2075f20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000007
R13: 0000564cf20725d0 R14: 00007f2129df8ea0 R15: 00007ffc34f70bb0
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):
0: c1 e8 03 shr $0x3,%eax
3: 42 0f b6 04 38 movzbl (%rax,%r15,1),%eax
8: 84 c0 test %al,%al
a: 0f 85 e6 00 00 00 jne 0xf6
10: 83 3d 83 de ba 14 00 cmpl $0x0,0x14bade83(%rip) # 0x14bade9a
17: 75 11 jne 0x2a
19: 65 8b 05 c2 fe b0 7e mov %gs:0x7eb0fec2(%rip),%eax # 0x7eb0fee2
20: 0f b6 c0 movzbl %al,%eax
23: 3d f5 00 00 00 cmp $0xf5,%eax
28: 73 58 jae 0x82
* 2a: 65 8b 05 b1 fe b0 7e mov %gs:0x7eb0feb1(%rip),%eax # 0x7eb0fee2 <-- trapping instruction
31: 25 ff ff ff 7f and $0x7fffffff,%eax
36: 39 f8 cmp %edi,%eax
38: 75 42 jne 0x7c
3a: 48 8b 5c 24 18 mov 0x18(%rsp),%rbx
3f: 48 rex.W