======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.1.7405/3801 is trying to acquire lock:
ffff88805779d558 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: spin_lock include/linux/spinlock.h:342 [inline]
ffff88805779d558 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: __netif_tx_lock include/linux/netdevice.h:4780 [inline]
ffff88805779d558 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: sch_direct_xmit+0x15f/0x4c0 net/sched/sch_generic.c:370
but task is already holding lock:
ffff888096b90ff0 (&hsr->seqnr_lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:348 [inline]
ffff888096b90ff0 (&hsr->seqnr_lock){+.-.}-{3:3}, at: send_hsr_supervision_frame+0x380/0xcb0 net/hsr/hsr_device.c:330
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (&hsr->seqnr_lock){+.-.}-{3:3}:
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:150 [inline]
_raw_spin_lock_bh+0x36/0x50 kernel/locking/spinlock.c:182
spin_lock_bh include/linux/spinlock.h:348 [inline]
hsr_dev_xmit+0x237/0x360 net/hsr/hsr_device.c:235
__netdev_start_xmit include/linux/netdevice.h:5367 [inline]
netdev_start_xmit include/linux/netdevice.h:5376 [inline]
xmit_one net/core/dev.c:3888 [inline]
dev_hard_start_xmit+0x2cd/0x830 net/core/dev.c:3904
__dev_queue_xmit+0x14d9/0x3950 net/core/dev.c:4870
NF_HOOK+0x33a/0x3c0 include/linux/netfilter.h:-1
arp_xmit+0x16c/0x270 net/ipv4/arp.c:665
arp_solicit+0xbe0/0xe40 net/ipv4/arp.c:392
neigh_probe net/core/neighbour.c:1096 [inline]
__neigh_event_send+0xf05/0x14d0 net/core/neighbour.c:1276
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:1603
neigh_output include/net/neighbour.h:556 [inline]
ip_finish_output2+0xca9/0x1070 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+0x621/0xd10 net/ipv4/ip_tunnel_core.c:97
ip_tunnel_xmit+0x193a/0x1f20 net/ipv4/ip_tunnel.c:845
__gre_xmit+0x19e/0x240 net/ipv4/ip_gre.c:491
erspan_xmit+0xa41/0x14d0 net/ipv4/ip_gre.c:750
__netdev_start_xmit include/linux/netdevice.h:5367 [inline]
netdev_start_xmit include/linux/netdevice.h:5376 [inline]
xmit_one net/core/dev.c:3888 [inline]
dev_hard_start_xmit+0x2cd/0x830 net/core/dev.c:3904
sch_direct_xmit+0x251/0x4c0 net/sched/sch_generic.c:372
__dev_xmit_skb net/core/dev.c:4209 [inline]
__dev_queue_xmit+0x180f/0x3950 net/core/dev.c:4831
NF_HOOK_COND include/linux/netfilter.h:307 [inline]
ip6_output+0x340/0x550 net/ipv6/ip6_output.c:246
dst_output include/net/dst.h:470 [inline]
NF_HOOK include/linux/netfilter.h:318 [inline]
ndisc_send_skb+0xd0b/0x1670 net/ipv6/ndisc.c:512
addrconf_rs_timer+0x395/0x6d0 net/ipv6/addrconf.c:4049
call_timer_fn+0x192/0x5e0 kernel/time/timer.c:1748
expire_timers kernel/time/timer.c:1799 [inline]
__run_timers kernel/time/timer.c:2374 [inline]
__run_timer_base+0x652/0x8b0 kernel/time/timer.c:2386
run_timer_base kernel/time/timer.c:2395 [inline]
run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2405
handle_softirqs+0x22a/0x840 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0xca/0x220 kernel/softirq.c:735
irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1061
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
__sanitizer_cov_trace_pc+0x0/0x70
get_next_corpse net/netfilter/nf_conntrack_core.c:2312 [inline]
nf_ct_iterate_cleanup+0x4d5/0x520 net/netfilter/nf_conntrack_core.c:2363
iterate_cleanup_work+0xe8/0x1a0 net/netfilter/nf_nat_masquerade.c:87
process_one_work kernel/workqueue.c:3302 [inline]
process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3385
worker_thread+0xa53/0xfc0 kernel/workqueue.c:3466
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
-> #0 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3165 [inline]
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain kernel/locking/lockdep.c:3908 [inline]
__lock_acquire+0x15a5/0x2cf0 kernel/locking/lockdep.c:5237
lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
__raw_spin_lock include/linux/spinlock_api_smp.h:158 [inline]
_raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:158
spin_lock include/linux/spinlock.h:342 [inline]
__netif_tx_lock include/linux/netdevice.h:4780 [inline]
sch_direct_xmit+0x15f/0x4c0 net/sched/sch_generic.c:370
__dev_xmit_skb net/core/dev.c:4209 [inline]
__dev_queue_xmit+0x180f/0x3950 net/core/dev.c:4831
dev_queue_xmit include/linux/netdevice.h:3417 [inline]
hsr_xmit net/hsr/hsr_forward.c:440 [inline]
hsr_forward_do net/hsr/hsr_forward.c:581 [inline]
hsr_forward_skb+0x167e/0x2a80 net/hsr/hsr_forward.c:743
send_hsr_supervision_frame+0x731/0xcb0 net/hsr/hsr_device.c:364
hsr_announce+0x1db/0x370 net/hsr/hsr_device.c:421
call_timer_fn+0x192/0x5e0 kernel/time/timer.c:1748
expire_timers kernel/time/timer.c:1799 [inline]
__run_timers kernel/time/timer.c:2374 [inline]
__run_timer_base+0x652/0x8b0 kernel/time/timer.c:2386
run_timer_base kernel/time/timer.c:2395 [inline]
run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2405
handle_softirqs+0x22a/0x840 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0xca/0x220 kernel/softirq.c:735
irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1061
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
netdev_notifier_info_to_dev include/linux/netdevice.h:3318 [inline]
j1939_netdev_notify+0x2b/0x310 net/can/j1939/main.c:363
notifier_call_chain+0x1ad/0x3d0 kernel/notifier.c:85
call_netdevice_notifiers_extack net/core/dev.c:2287 [inline]
call_netdevice_notifiers net/core/dev.c:2301 [inline]
unregister_netdevice_many_notify+0x17a5/0x22c0 net/core/dev.c:12418
ops_exit_rtnl_list net/core/net_namespace.c:187 [inline]
ops_undo_list+0x3d3/0x940 net/core/net_namespace.c:248
setup_net+0x2f0/0x340 net/core/net_namespace.c:462
copy_net_ns+0x50e/0x730 net/core/net_namespace.c:579
create_new_namespaces+0x3e7/0x6a0 kernel/nsproxy.c:132
unshare_nsproxy_namespaces+0x149/0x190 kernel/nsproxy.c:234
ksys_unshare+0x57d/0x9f0 kernel/fork.c:3245
__do_sys_unshare kernel/fork.c:3319 [inline]
__se_sys_unshare kernel/fork.c:3317 [inline]
__x64_sys_unshare+0x38/0x50 kernel/fork.c:3317
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&hsr->seqnr_lock);
lock(&qdisc_xmit_lock_key#4);
lock(&hsr->seqnr_lock);
lock(&qdisc_xmit_lock_key#4);
*** DEADLOCK ***
8 locks held by syz.1.7405/3801:
#0: ffffffff8fdc0b68 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x4f7/0x730 net/core/net_namespace.c:575
#1: ffffffff8fdcf840 (rtnl_mutex){+.+.}-{4:4}, at: ops_exit_rtnl_list net/core/net_namespace.c:173 [inline]
#1: ffffffff8fdcf840 (rtnl_mutex){+.+.}-{4:4}, at: ops_undo_list+0x2a4/0x940 net/core/net_namespace.c:248
#2: ffffc90000007cc0 ((&hsr->announce_timer)){+.-.}-{0:0}, at: call_timer_fn+0xd4/0x5e0 kernel/time/timer.c:1745
#3: ffffffff8e95cd60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#3: ffffffff8e95cd60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#3: ffffffff8e95cd60 (rcu_read_lock){....}-{1:3}, at: hsr_announce+0x89/0x370 net/hsr/hsr_device.c:419
#4: ffff888096b90ff0 (&hsr->seqnr_lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:348 [inline]
#4: ffff888096b90ff0 (&hsr->seqnr_lock){+.-.}-{3:3}, at: send_hsr_supervision_frame+0x380/0xcb0 net/hsr/hsr_device.c:330
#5: ffffffff8e95cd60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#5: ffffffff8e95cd60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#5: ffffffff8e95cd60 (rcu_read_lock){....}-{1:3}, at: hsr_forward_skb+0xbb/0x2a80 net/hsr/hsr_forward.c:738
#6: ffffffff8e95cdc0 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline]
#6: ffffffff8e95cdc0 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:891 [inline]
#6: ffffffff8e95cdc0 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x2b6/0x3950 net/core/dev.c:4791
#7: ffff88807ebce228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: spin_trylock include/linux/spinlock.h:354 [inline]
#7: ffff88807ebce228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: qdisc_run_begin include/net/sch_generic.h:205 [inline]
#7: ffff88807ebce228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: __dev_xmit_skb net/core/dev.c:4196 [inline]
#7: ffff88807ebce228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: __dev_queue_xmit+0x11a6/0x3950 net/core/dev.c:4831
stack backtrace:
CPU: 0 UID: 0 PID: 3801 Comm: syz.1.7405 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
print_circular_bug+0x2e1/0x300 kernel/locking/lockdep.c:2043
check_noncircular+0x12e/0x150 kernel/locking/lockdep.c:2175
check_prev_add kernel/locking/lockdep.c:3165 [inline]
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain kernel/locking/lockdep.c:3908 [inline]
__lock_acquire+0x15a5/0x2cf0 kernel/locking/lockdep.c:5237
lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
__raw_spin_lock include/linux/spinlock_api_smp.h:158 [inline]
_raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:158
spin_lock include/linux/spinlock.h:342 [inline]
__netif_tx_lock include/linux/netdevice.h:4780 [inline]
sch_direct_xmit+0x15f/0x4c0 net/sched/sch_generic.c:370
__dev_xmit_skb net/core/dev.c:4209 [inline]
__dev_queue_xmit+0x180f/0x3950 net/core/dev.c:4831
dev_queue_xmit include/linux/netdevice.h:3417 [inline]
hsr_xmit net/hsr/hsr_forward.c:440 [inline]
hsr_forward_do net/hsr/hsr_forward.c:581 [inline]
hsr_forward_skb+0x167e/0x2a80 net/hsr/hsr_forward.c:743
send_hsr_supervision_frame+0x731/0xcb0 net/hsr/hsr_device.c:364
hsr_announce+0x1db/0x370 net/hsr/hsr_device.c:421
call_timer_fn+0x192/0x5e0 kernel/time/timer.c:1748
expire_timers kernel/time/timer.c:1799 [inline]
__run_timers kernel/time/timer.c:2374 [inline]
__run_timer_base+0x652/0x8b0 kernel/time/timer.c:2386
run_timer_base kernel/time/timer.c:2395 [inline]
run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2405
handle_softirqs+0x22a/0x840 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0xca/0x220 kernel/softirq.c:735
irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1061
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:netdev_notifier_info_to_dev include/linux/netdevice.h:3318 [inline]
RIP: 0010:j1939_netdev_notify+0x2b/0x310 net/can/j1939/main.c:363
Code: 0f 1e fa 55 41 57 41 56 41 55 41 54 53 50 49 89 d6 48 89 f3 49 bc 00 00 00 00 00 fc ff df e8 9c 15 2d f7 4c 89 f0 48 c1 e8 03 <42> 80 3c 20 00 74 08 4c 89 f7 e8 86 50 98 f7 4d 8b 36 4d 8d be f8
RSP: 0018:ffffc9000570f8d0 EFLAGS: 00000a02
RAX: 1ffff92000ae1f4c RBX: 0000000000000006 RCX: ffff888050a98000
RDX: 0000000000000000 RSI: 0000000000000006 RDI: ffffffff8ff4e8c0
RBP: 00000000ffffffbb R08: ffffffff9030cdf7 R09: 1ffffffff20619be
R10: dffffc0000000000 R11: ffffffff8a989670 R12: dffffc0000000000
R13: 0000000000000000 R14: ffffc9000570fa60 R15: 1ffffffff1fe9d18
notifier_call_chain+0x1ad/0x3d0 kernel/notifier.c:85
call_netdevice_notifiers_extack net/core/dev.c:2287 [inline]
call_netdevice_notifiers net/core/dev.c:2301 [inline]
unregister_netdevice_many_notify+0x17a5/0x22c0 net/core/dev.c:12418
ops_exit_rtnl_list net/core/net_namespace.c:187 [inline]
ops_undo_list+0x3d3/0x940 net/core/net_namespace.c:248
setup_net+0x2f0/0x340 net/core/net_namespace.c:462
copy_net_ns+0x50e/0x730 net/core/net_namespace.c:579
create_new_namespaces+0x3e7/0x6a0 kernel/nsproxy.c:132
unshare_nsproxy_namespaces+0x149/0x190 kernel/nsproxy.c:234
ksys_unshare+0x57d/0x9f0 kernel/fork.c:3245
__do_sys_unshare kernel/fork.c:3319 [inline]
__se_sys_unshare kernel/fork.c:3317 [inline]
__x64_sys_unshare+0x38/0x50 kernel/fork.c:3317
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f623b99cdd9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f623c84f028 EFLAGS: 00000246 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 00007f623bc16090 RCX: 00007f623b99cdd9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000006a040000
RBP: 00007f623ba32d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f623bc16128 R14: 00007f623bc16090 R15: 00007ffcb042f828
bridge0: port 1(bridge_slave_0) entered learning state
----------------
Code disassembly (best guess):
0: 0f 1e fa nop %edx
3: 55 push %rbp
4: 41 57 push %r15
6: 41 56 push %r14
8: 41 55 push %r13
a: 41 54 push %r12
c: 53 push %rbx
d: 50 push %rax
e: 49 89 d6 mov %rdx,%r14
11: 48 89 f3 mov %rsi,%rbx
14: 49 bc 00 00 00 00 00 movabs $0xdffffc0000000000,%r12
1b: fc ff df
1e: e8 9c 15 2d f7 call 0xf72d15bf
23: 4c 89 f0 mov %r14,%rax
26: 48 c1 e8 03 shr $0x3,%rax
* 2a: 42 80 3c 20 00 cmpb $0x0,(%rax,%r12,1) <-- trapping instruction
2f: 74 08 je 0x39
31: 4c 89 f7 mov %r14,%rdi
34: e8 86 50 98 f7 call 0xf79850bf
39: 4d 8b 36 mov (%r14),%r14
3c: 4d rex.WRB
3d: 8d .byte 0x8d
3e: be .byte 0xbe
3f: f8 clc