============================================
WARNING: possible recursive locking detected
6.16.0-rc3-syzkaller-00922-g8f240030794c #0 Not tainted
--------------------------------------------
syz.5.2374/14699 is trying to acquire lock:
ffff888033d70f30 (&hsr->seqnr_lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:356 [inline]
ffff888033d70f30 (&hsr->seqnr_lock){+.-.}-{3:3}, at: hsr_dev_xmit+0x19a/0x220 net/hsr/hsr_device.c:234
but task is already holding lock:
ffff888030564f30 (&hsr->seqnr_lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:356 [inline]
ffff888030564f30 (&hsr->seqnr_lock){+.-.}-{3:3}, at: hsr_dev_xmit+0x19a/0x220 net/hsr/hsr_device.c:234
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(&hsr->seqnr_lock);
lock(&hsr->seqnr_lock);
*** DEADLOCK ***
May be due to missing lock nesting notation
11 locks held by syz.5.2374/14699:
#0: ffffffff8f505b50 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x304/0x4d0 net/core/net_namespace.c:570
#1: ffff88801ced8998 (&s->s_inode_list_lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock.h:351 [inline]
#1: ffff88801ced8998 (&s->s_inode_list_lock){+.+.}-{3:3}, at: nr_blockdev_pages+0x2f/0x110 block/bdev.c:521
#2: ffffc90000007be0 ((&ndev->rs_timer)){+.-.}-{0:0}, at: call_timer_fn+0xbe/0x5f0 kernel/time/timer.c:1744
#3: ffffffff8e13ee60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#3: ffffffff8e13ee60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#3: ffffffff8e13ee60 (rcu_read_lock){....}-{1:3}, at: ndisc_send_skb+0x208/0x1400 net/ipv6/ndisc.c:484
#4: ffffffff8e13ee60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#4: ffffffff8e13ee60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#4: ffffffff8e13ee60 (rcu_read_lock){....}-{1:3}, at: ip6_finish_output2+0x701/0x16a0 net/ipv6/ip6_output.c:126
#5: ffffffff8e13eec0 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline]
#5: ffffffff8e13eec0 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:892 [inline]
#5: ffffffff8e13eec0 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x27e/0x3a70 net/core/dev.c:4636
#6: ffff888030564f30 (&hsr->seqnr_lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:356 [inline]
#6: ffff888030564f30 (&hsr->seqnr_lock){+.-.}-{3:3}, at: hsr_dev_xmit+0x19a/0x220 net/hsr/hsr_device.c:234
#7: ffffffff8e13ee60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#7: ffffffff8e13ee60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#7: ffffffff8e13ee60 (rcu_read_lock){....}-{1:3}, at: hsr_forward_skb+0x9e/0x2860 net/hsr/hsr_forward.c:728
#8: ffffffff8e13eec0 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline]
#8: ffffffff8e13eec0 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:892 [inline]
#8: ffffffff8e13eec0 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x27e/0x3a70 net/core/dev.c:4636
#9: ffffffff8e13ee60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#9: ffffffff8e13ee60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#9: ffffffff8e13ee60 (rcu_read_lock){....}-{1:3}, at: br_dev_xmit+0x185/0x1840 net/bridge/br_device.c:52
#10: ffffffff8e13eec0 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline]
#10: ffffffff8e13eec0 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:892 [inline]
#10: ffffffff8e13eec0 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x27e/0x3a70 net/core/dev.c:4636
stack backtrace:
CPU: 0 UID: 0 PID: 14699 Comm: syz.5.2374 Not tainted 6.16.0-rc3-syzkaller-00922-g8f240030794c #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
print_deadlock_bug+0x28b/0x2a0 kernel/locking/lockdep.c:3044
check_deadlock kernel/locking/lockdep.c:3096 [inline]
validate_chain+0x1a3f/0x2140 kernel/locking/lockdep.c:3898
__lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5240
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline]
_raw_spin_lock_bh+0x36/0x50 kernel/locking/spinlock.c:178
spin_lock_bh include/linux/spinlock.h:356 [inline]
hsr_dev_xmit+0x19a/0x220 net/hsr/hsr_device.c:234
__netdev_start_xmit include/linux/netdevice.h:5217 [inline]
netdev_start_xmit include/linux/netdevice.h:5226 [inline]
xmit_one net/core/dev.c:3828 [inline]
dev_hard_start_xmit+0x2d7/0x830 net/core/dev.c:3844
__dev_queue_xmit+0x1adf/0x3a70 net/core/dev.c:4711
dev_queue_xmit include/linux/netdevice.h:3358 [inline]
br_dev_queue_push_xmit+0x6c5/0x890 net/bridge/br_forward.c:53
NF_HOOK+0x320/0x3c0 include/linux/netfilter.h:317
br_forward_finish+0xd3/0x130 net/bridge/br_forward.c:66
NF_HOOK+0x320/0x3c0 include/linux/netfilter.h:317
__br_forward+0x41e/0x600 net/bridge/br_forward.c:115
deliver_clone net/bridge/br_forward.c:131 [inline]
maybe_deliver+0xb5/0x160 net/bridge/br_forward.c:190
br_flood+0x31a/0x6a0 net/bridge/br_forward.c:237
br_dev_xmit+0x11b3/0x1840 net/bridge/br_device.c:108
__netdev_start_xmit include/linux/netdevice.h:5217 [inline]
netdev_start_xmit include/linux/netdevice.h:5226 [inline]
xmit_one net/core/dev.c:3828 [inline]
dev_hard_start_xmit+0x2d7/0x830 net/core/dev.c:3844
__dev_queue_xmit+0x1adf/0x3a70 net/core/dev.c:4711
dev_queue_xmit include/linux/netdevice.h:3358 [inline]
hsr_xmit net/hsr/hsr_forward.c:430 [inline]
hsr_forward_do net/hsr/hsr_forward.c:571 [inline]
hsr_forward_skb+0x158b/0x2860 net/hsr/hsr_forward.c:733
hsr_dev_xmit+0x1a5/0x220 net/hsr/hsr_device.c:235
__netdev_start_xmit include/linux/netdevice.h:5217 [inline]
netdev_start_xmit include/linux/netdevice.h:5226 [inline]
xmit_one net/core/dev.c:3828 [inline]
dev_hard_start_xmit+0x2d7/0x830 net/core/dev.c:3844
__dev_queue_xmit+0x1adf/0x3a70 net/core/dev.c:4711
neigh_output include/net/neighbour.h:542 [inline]
ip6_finish_output2+0x11fe/0x16a0 net/ipv6/ip6_output.c:141
__ip6_finish_output net/ipv6/ip6_output.c:-1 [inline]
ip6_finish_output+0x234/0x7d0 net/ipv6/ip6_output.c:226
NF_HOOK include/linux/netfilter.h:317 [inline]
ndisc_send_skb+0xb47/0x1400 net/ipv6/ndisc.c:513
addrconf_rs_timer+0x369/0x670 net/ipv6/addrconf.c:4041
call_timer_fn+0x17e/0x5f0 kernel/time/timer.c:1747
expire_timers kernel/time/timer.c:1798 [inline]
__run_timers kernel/time/timer.c:2372 [inline]
__run_timer_base+0x61a/0x860 kernel/time/timer.c:2384
run_timer_base kernel/time/timer.c:2393 [inline]
run_timer_softirq+0xb7/0x180 kernel/time/timer.c:2403
handle_softirqs+0x286/0x870 kernel/softirq.c:579
__do_softirq kernel/softirq.c:613 [inline]
invoke_softirq kernel/softirq.c:453 [inline]
__irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:680
irq_exit_rcu+0x9/0x30 kernel/softirq.c:696
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1050
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:nr_blockdev_pages+0xaa/0x110 block/bdev.c:522
Code: c1 85 fd 4d 8b 6d 00 49 01 dd 4c 89 e8 48 c1 e8 03 80 3c 28 00 74 08 4c 89 ef e8 81 c1 85 fd 4c 89 e0 48 c1 e8 03 4d 03 7d 00 <80> 3c 28 00 74 08 4c 89 e7 e8 68 c1 85 fd 4d 8b 24 24 4d 39 f4 74
RSP: 0018:ffffc9000468f998 EFLAGS: 00000206
RAX: 1ffff11004581273 RBX: 0000000000000110 RCX: ffff88807f41da00
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffffc9000468f920
RBP: dffffc0000000000 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff520008d1f24 R12: ffff888022c09398
R13: ffff888022c09508 R14: ffff88801ced89c0 R15: 00000000000003ac
si_meminfo+0x10f/0x180 mm/show_mem.c:80
nfsd4_init_leases_net+0x1f2/0x3b0 fs/nfsd/nfs4state.c:4855
nfsd_net_init+0x2b8/0x480 fs/nfsd/nfsctl.c:2218
ops_init+0x359/0x5c0 net/core/net_namespace.c:138
setup_net+0x219/0x4b0 net/core/net_namespace.c:442
copy_net_ns+0x31b/0x4d0 net/core/net_namespace.c:574
create_new_namespaces+0x3f3/0x720 kernel/nsproxy.c:110
unshare_nsproxy_namespaces+0x11c/0x170 kernel/nsproxy.c:218
ksys_unshare+0x4c8/0x8c0 kernel/fork.c:3121
__do_sys_unshare kernel/fork.c:3192 [inline]
__se_sys_unshare kernel/fork.c:3190 [inline]
__x64_sys_unshare+0x38/0x50 kernel/fork.c:3190
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff09718e929
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:00007ff0980c0038 EFLAGS: 00000246 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 00007ff0973b5fa0 RCX: 00007ff09718e929
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000064000600
RBP: 00007ff097210b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007ff0973b5fa0 R15: 00007ffeb190f3b8
----------------
Code disassembly (best guess):
0: c1 85 fd 4d 8b 6d 00 roll $0x0,0x6d8b4dfd(%rbp)
7: 49 01 dd add %rbx,%r13
a: 4c 89 e8 mov %r13,%rax
d: 48 c1 e8 03 shr $0x3,%rax
11: 80 3c 28 00 cmpb $0x0,(%rax,%rbp,1)
15: 74 08 je 0x1f
17: 4c 89 ef mov %r13,%rdi
1a: e8 81 c1 85 fd call 0xfd85c1a0
1f: 4c 89 e0 mov %r12,%rax
22: 48 c1 e8 03 shr $0x3,%rax
26: 4d 03 7d 00 add 0x0(%r13),%r15
* 2a: 80 3c 28 00 cmpb $0x0,(%rax,%rbp,1) <-- trapping instruction
2e: 74 08 je 0x38
30: 4c 89 e7 mov %r12,%rdi
33: e8 68 c1 85 fd call 0xfd85c1a0
38: 4d 8b 24 24 mov (%r12),%r12
3c: 4d 39 f4 cmp %r14,%r12
3f: 74 .byte 0x74