============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
syz.1.1832/12992 is trying to acquire lock:
ffff88801e3b9958 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: spin_lock include/linux/spinlock.h:351 [inline]
ffff88801e3b9958 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: __netif_tx_lock include/linux/netdevice.h:4710 [inline]
ffff88801e3b9958 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: sch_direct_xmit+0x153/0x4b0 net/sched/sch_generic.c:345
but task is already holding lock:
ffff88807ce05d58 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: spin_lock include/linux/spinlock.h:351 [inline]
ffff88807ce05d58 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: __netif_tx_lock include/linux/netdevice.h:4710 [inline]
ffff88807ce05d58 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: __dev_queue_xmit+0x117b/0x31c0 net/core/dev.c:4814
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
14 locks held by syz.1.1832/12992:
#0: ffffffff99c83f78 (&rdma_nl_types[idx].sem){.+.+}-{4:4}, at: rdma_nl_rcv_msg drivers/infiniband/core/netlink.c:164 [inline]
#0: ffffffff99c83f78 (&rdma_nl_types[idx].sem){.+.+}-{4:4}, at: rdma_nl_rcv_skb drivers/infiniband/core/netlink.c:239 [inline]
#0: ffffffff99c83f78 (&rdma_nl_types[idx].sem){.+.+}-{4:4}, at: rdma_nl_rcv+0x302/0x980 drivers/infiniband/core/netlink.c:259
#1: ffff88807bec0700 (&device->unregistration_lock){+.+.}-{4:4}, at: __ib_unregister_device+0x284/0x3f0 drivers/infiniband/core/device.c:1551
#2: ffff88801bef0188 (&root->kernfs_rwsem){++++}-{4:4}, at: kernfs_remove_by_name_ns+0x3d/0x130 fs/kernfs/dir.c:1717
#3: ffff88801bef0080 (&root->kernfs_idr_lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock.h:351 [inline]
#3: ffff88801bef0080 (&root->kernfs_idr_lock){+.+.}-{3:3}, at: kernfs_put+0x13c/0x470 fs/kernfs/dir.c:587
#4: ffffc90000a08ce0 ((&ndev->rs_timer)){+.-.}-{0:0}, at: call_timer_fn+0xbe/0x590 kernel/time/timer.c:1745
#5: ffffffff8df41aa0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#5: ffffffff8df41aa0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#5: ffffffff8df41aa0 (rcu_read_lock){....}-{1:3}, at: ndisc_send_skb+0x1e4/0x1510 net/ipv6/ndisc.c:482
#6: ffffffff8df41aa0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#6: ffffffff8df41aa0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#6: ffffffff8df41aa0 (rcu_read_lock){....}-{1:3}, at: ip6_output+0x126/0x550 net/ipv6/ip6_output.c:235
#7: ffffffff8df41b00 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline]
#7: ffffffff8df41b00 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:918 [inline]
#7: ffffffff8df41b00 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x289/0x31c0 net/core/dev.c:4743
#8: ffff88807ce05d58 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: spin_lock include/linux/spinlock.h:351 [inline]
#8: ffff88807ce05d58 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: __netif_tx_lock include/linux/netdevice.h:4710 [inline]
#8: ffff88807ce05d58 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: __dev_queue_xmit+0x117b/0x31c0 net/core/dev.c:4814
#9: ffffffff8df41aa0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#9: ffffffff8df41aa0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#9: ffffffff8df41aa0 (rcu_read_lock){....}-{1:3}, at: ip_output+0x5b/0x450 net/ipv4/ip_output.c:433
#10: ffffffff8df41aa0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#10: ffffffff8df41aa0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#10: ffffffff8df41aa0 (rcu_read_lock){....}-{1:3}, at: ip_finish_output2+0x3d0/0x1000 net/ipv4/ip_output.c:230
#11: ffffffff8df41aa0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#11: ffffffff8df41aa0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#11: ffffffff8df41aa0 (rcu_read_lock){....}-{1:3}, at: arp_xmit+0x23/0x270 net/ipv4/arp.c:663
#12: ffffffff8df41b00 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline]
#12: ffffffff8df41b00 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:918 [inline]
#12: ffffffff8df41b00 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x289/0x31c0 net/core/dev.c:4743
#13: ffff88807c1fc228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#3){+...}-{3:3}, at: spin_trylock include/linux/spinlock.h:361 [inline]
#13: ffff88807c1fc228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#3){+...}-{3:3}, at: qdisc_run_begin include/net/sch_generic.h:202 [inline]
#13: ffff88807c1fc228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#3){+...}-{3:3}, at: __dev_xmit_skb net/core/dev.c:4155 [inline]
#13: ffff88807c1fc228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#3){+...}-{3:3}, at: __dev_queue_xmit+0xeb9/0x31c0 net/core/dev.c:4784
stack backtrace:
CPU: 1 UID: 0 PID: 12992 Comm: syz.1.1832 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
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+0x2540/0x2cf0 kernel/locking/lockdep.c:5237
lock_acquire+0x107/0x340 kernel/locking/lockdep.c:5868
__raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
_raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
spin_lock include/linux/spinlock.h:351 [inline]
__netif_tx_lock include/linux/netdevice.h:4710 [inline]
sch_direct_xmit+0x153/0x4b0 net/sched/sch_generic.c:345
__dev_xmit_skb net/core/dev.c:4168 [inline]
__dev_queue_xmit+0x1379/0x31c0 net/core/dev.c:4784
NF_HOOK+0x310/0x3a0 include/linux/netfilter.h:-1
arp_xmit+0x16c/0x270 net/ipv4/arp.c:665
arp_solicit+0xbbd/0xe10 net/ipv4/arp.c:392
neigh_probe net/core/neighbour.c:1097 [inline]
__neigh_event_send+0xf3e/0x1520 net/core/neighbour.c:1270
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:1578
neigh_output include/net/neighbour.h:556 [inline]
ip_finish_output2+0xbb6/0x1000 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+0x5f8/0xa90 net/ipv4/ip_tunnel_core.c:84
ip_tunnel_xmit+0x1c41/0x2390 net/ipv4/ip_tunnel.c:845
__gre_xmit net/ipv4/ip_gre.c:490 [inline]
ipgre_xmit+0x89e/0xc50 net/ipv4/ip_gre.c:694
__netdev_start_xmit include/linux/netdevice.h:5273 [inline]
netdev_start_xmit include/linux/netdevice.h:5282 [inline]
xmit_one net/core/dev.c:3852 [inline]
dev_hard_start_xmit+0x2cd/0x800 net/core/dev.c:3868
__dev_queue_xmit+0x149d/0x31c0 net/core/dev.c:4818
NF_HOOK_COND include/linux/netfilter.h:307 [inline]
ip6_output+0x340/0x550 net/ipv6/ip6_output.c:247
NF_HOOK include/linux/netfilter.h:318 [inline]
ndisc_send_skb+0xbce/0x1510 net/ipv6/ndisc.c:512
addrconf_rs_timer+0x369/0x6a0 net/ipv6/addrconf.c:4037
call_timer_fn+0x16e/0x590 kernel/time/timer.c:1748
expire_timers kernel/time/timer.c:1799 [inline]
__run_timers kernel/time/timer.c:2373 [inline]
__run_timer_base+0x61a/0x860 kernel/time/timer.c:2385
run_timer_base kernel/time/timer.c:2394 [inline]
run_timer_softirq+0xb7/0x180 kernel/time/timer.c:2404
handle_softirqs+0x22b/0x7c0 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0x60/0x150 kernel/softirq.c:723
irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1056
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:variable_test_bit arch/x86/include/asm/bitops.h:222 [inline]
RIP: 0010:arch_test_bit arch/x86/include/asm/bitops.h:233 [inline]
RIP: 0010:_test_bit include/asm-generic/bitops/instrumented-non-atomic.h:142 [inline]
RIP: 0010:tag_get lib/radix-tree.c:115 [inline]
RIP: 0010:node_tag_set lib/radix-tree.c:943 [inline]
RIP: 0010:__radix_tree_delete+0x123/0x3d0 lib/radix-tree.c:1373
Code: dd 48 89 d8 48 c1 e8 06 4c 8d 2c c5 28 02 00 00 49 01 ed 4c 89 ef be 08 00 00 00 e8 d7 14 d2 f6 31 f6 48 0f a3 9d 28 02 00 00 <41> 0f 93 c7 40 0f 92 c6 bf 02 00 00 00 e8 1b f5 6b f6 45 84 ff 0f
RSP: 0018:ffffc9000c2f6e68 EFLAGS: 00000247
RAX: 0000000000000001 RBX: 0000000000000004 RCX: ffffffff8b550589
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff888054190a68
RBP: ffff888054190840 R08: ffff888054190a6f R09: 1ffff1100a83214d
R10: dffffc0000000000 R11: ffffed100a83214e R12: 1ffff110037de00a
R13: ffff888054190a68 R14: ffff8880541902c0 R15: ffff888054190301
radix_tree_delete_item+0x2b6/0x400 lib/radix-tree.c:1430
kernfs_put+0x170/0x470 fs/kernfs/dir.c:588
kernfs_remove_by_name_ns+0xb7/0x130 fs/kernfs/dir.c:1723
kernfs_remove_by_name include/linux/kernfs.h:633 [inline]
remove_files fs/sysfs/group.c:28 [inline]
sysfs_remove_group+0xfc/0x2f0 fs/sysfs/group.c:328
sysfs_remove_groups+0x54/0xb0 fs/sysfs/group.c:352
destroy_gid_attrs drivers/infiniband/core/sysfs.c:1182 [inline]
ib_free_port_attrs+0xc5/0x3b0 drivers/infiniband/core/sysfs.c:1407
__ib_unregister_device+0x2f1/0x3f0 drivers/infiniband/core/device.c:1561
ib_unregister_device_and_put+0xb8/0xf0 drivers/infiniband/core/device.c:1620
nldev_dellink+0x2d1/0x320 drivers/infiniband/core/nldev.c:1827
rdma_nl_rcv_msg drivers/infiniband/core/netlink.c:-1 [inline]
rdma_nl_rcv_skb drivers/infiniband/core/netlink.c:239 [inline]
rdma_nl_rcv+0x6ae/0x980 drivers/infiniband/core/netlink.c:259
netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1344
netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1894
sock_sendmsg_nosec net/socket.c:727 [inline]
__sock_sendmsg+0x21c/0x270 net/socket.c:742
____sys_sendmsg+0x505/0x820 net/socket.c:2592
___sys_sendmsg+0x21f/0x2a0 net/socket.c:2646
__sys_sendmsg net/socket.c:2678 [inline]
__do_sys_sendmsg net/socket.c:2683 [inline]
__se_sys_sendmsg net/socket.c:2681 [inline]
__x64_sys_sendmsg+0x19b/0x260 net/socket.c:2681
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7facb898f749
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007facb9747038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007facb8be6090 RCX: 00007facb898f749
RDX: 0000000000000000 RSI: 00002000000002c0 RDI: 0000000000000008
RBP: 00007facb8a13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007facb8be6128 R14: 00007facb8be6090 R15: 00007ffda75c9b98
----------------
Code disassembly (best guess), 1 bytes skipped:
0: 48 89 d8 mov %rbx,%rax
3: 48 c1 e8 06 shr $0x6,%rax
7: 4c 8d 2c c5 28 02 00 lea 0x228(,%rax,8),%r13
e: 00
f: 49 01 ed add %rbp,%r13
12: 4c 89 ef mov %r13,%rdi
15: be 08 00 00 00 mov $0x8,%esi
1a: e8 d7 14 d2 f6 call 0xf6d214f6
1f: 31 f6 xor %esi,%esi
21: 48 0f a3 9d 28 02 00 bt %rbx,0x228(%rbp)
28: 00
* 29: 41 0f 93 c7 setae %r15b <-- trapping instruction
2d: 40 0f 92 c6 setb %sil
31: bf 02 00 00 00 mov $0x2,%edi
36: e8 1b f5 6b f6 call 0xf66bf556
3b: 45 84 ff test %r15b,%r15b
3e: 0f .byte 0xf