============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
syz-executor/10546 is trying to acquire lock:
ffff888073a0c218 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:364 [inline]
ffff888073a0c218 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3909 [inline]
ffff888073a0c218 (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:
ffff8880741df258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: spin_trylock include/linux/spinlock.h:374 [inline]
ffff8880741df258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:173 [inline]
ffff8880741df258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3871 [inline]
ffff8880741df258 (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
12 locks held by syz-executor/10546:
#0: ffff888077f3b228 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff888077f3b228 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x2b9/0xc80 arch/x86/mm/fault.c:1298
#1: ffffffff8c31eaa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:312
#2: ffff888062b47798 (ptlock_ptr(page)#2){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:364 [inline]
#2: ffff888062b47798 (ptlock_ptr(page)#2){+.+.}-{2:2}, at: filemap_map_pages+0xba0/0x13b0 mm/filemap.c:3324
#3: ffffc90000007be0 ((&ndev->rs_timer)){+.-.}-{0:0}, at: lockdep_copy_map include/linux/lockdep.h:45 [inline]
#3: ffffc90000007be0 ((&ndev->rs_timer)){+.-.}-{0:0}, at: call_timer_fn+0xca/0x540 kernel/time/timer.c:1441
#4: ffffffff8c31eaa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:312
#5: ffffffff8c31eb00 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:313
#6: ffffffff8c31eb00 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:313
#7: ffffffff8c31eaa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:312
#8: ffffffff8c31eb00 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:313
#9: ffff8880741df258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: spin_trylock include/linux/spinlock.h:374 [inline]
#9: ffff8880741df258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: qdisc_run_begin include/net/sch_generic.h:173 [inline]
#9: ffff8880741df258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_xmit_skb net/core/dev.c:3871 [inline]
#9: ffff8880741df258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock){+.-.}-{2:2}, at: __dev_queue_xmit+0x1120/0x2fd0 net/core/dev.c:4253
#10: ffffffff8c31eb00 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:313
#11: ffffffff8c31eb00 (rcu_read_lock_bh){....}-{1:2}, at: rcu_lock_acquire+0x9/0x30 include/linux/rcupdate.h:313
stack backtrace:
CPU: 0 PID: 10546 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:i_size_read include/linux/fs.h:895 [inline]
RIP: 0010:next_uptodate_page+0x515/0x8b0 mm/filemap.c:3271
Code: 20 48 89 f8 48 c1 e8 03 80 3c 28 00 74 0a e8 42 83 1e 00 48 8b 7c 24 20 4c 8b 3f 49 83 c7 50 4c 89 f8 48 c1 e8 03 80 3c 28 00 <74> 08 4c 89 ff e8 21 83 1e 00 4d 8b 3f b8 ff 0f 00 00 49 01 c7 4c
RSP: 0000:ffffc90003ac7ad8 EFLAGS: 00000246
RAX: 1ffff1100e95e05e RBX: ffffea0001ccd640 RCX: ffff8880720c0000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff888074af04c8
RBP: dffffc0000000000 R08: ffffea0001ccd647 R09: 1ffffd4000399ac8
R10: dffffc0000000000 R11: fffff94000399ac9 R12: ffffc90003ac7c08
R13: ffffea0001ccd648 R14: 1ffffd4000399ac9 R15: ffff888074af02f0
next_map_page mm/filemap.c:3296 [inline]
filemap_map_pages+0xee0/0x13b0 mm/filemap.c:3352
do_fault_around mm/memory.c:4243 [inline]
do_read_fault mm/memory.c:4258 [inline]
do_fault mm/memory.c:4392 [inline]
handle_pte_fault mm/memory.c:4650 [inline]
__handle_mm_fault mm/memory.c:4785 [inline]
handle_mm_fault+0x25bc/0x4410 mm/memory.c:4883
do_user_addr_fault+0x489/0xc80 arch/x86/mm/fault.c:1357
handle_page_fault arch/x86/mm/fault.c:1445 [inline]
exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1501
asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:606
RIP: 0033:0x7f16ce506430
Code: 8b 54 24 18 64 48 2b 14 25 28 00 00 00 75 08 48 81 c4 d8 00 00 00 c3 e8 be 3f 05 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 <48> 81 ec d8 00 00 00 48 89 4c 24 38 4c 89 44 24 40 4c 89 4c 24 48
RSP: 002b:00007fffd02c42c8 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000007
RDX: 00007f16ce5c79e4 RSI: 0000000000000040 RDI: 00007fffd02c4360
RBP: 00007fffd02c430c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000000007f
R13: 00000000000927c0 R14: 000000000005db06 R15: 00007fffd02c4360
----------------
Code disassembly (best guess):
0: 20 48 89 and %cl,-0x77(%rax)
3: f8 clc
4: 48 c1 e8 03 shr $0x3,%rax
8: 80 3c 28 00 cmpb $0x0,(%rax,%rbp,1)
c: 74 0a je 0x18
e: e8 42 83 1e 00 call 0x1e8355
13: 48 8b 7c 24 20 mov 0x20(%rsp),%rdi
18: 4c 8b 3f mov (%rdi),%r15
1b: 49 83 c7 50 add $0x50,%r15
1f: 4c 89 f8 mov %r15,%rax
22: 48 c1 e8 03 shr $0x3,%rax
26: 80 3c 28 00 cmpb $0x0,(%rax,%rbp,1)
* 2a: 74 08 je 0x34 <-- trapping instruction
2c: 4c 89 ff mov %r15,%rdi
2f: e8 21 83 1e 00 call 0x1e8355
34: 4d 8b 3f mov (%r15),%r15
37: b8 ff 0f 00 00 mov $0xfff,%eax
3c: 49 01 c7 add %rax,%r15
3f: 4c rex.WR