============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
syz.1.9506/2385 is trying to acquire lock:
ffff888034486f30 (&hsr->seqnr_lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:356 [inline]
ffff888034486f30 (&hsr->seqnr_lock){+.-.}-{3:3}, at: hsr_dev_xmit+0x237/0x360 net/hsr/hsr_device.c:235
but task is already holding lock:
ffff88803beb0f30 (&hsr->seqnr_lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:356 [inline]
ffff88803beb0f30 (&hsr->seqnr_lock){+.-.}-{3:3}, at: send_hsr_supervision_frame+0x380/0xcb0 net/hsr/hsr_device.c:330
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
13 locks held by syz.1.9506/2385:
#0: ffffffff8f2bf730 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x337/0x4e0 net/core/net_namespace.c:577
#1: ffffffff8f038410 (devices_rwsem){++++}-{4:4}, at: rdma_dev_init_net+0x19a/0x270 drivers/infiniband/core/device.c:1215
#2: ffffffff8f0385d0 (rdma_nets_rwsem){++++}-{4:4}, at: rdma_dev_init_net+0x1d2/0x270 drivers/infiniband/core/device.c:1220
#3: ffff888065120f98 (&device->compat_devs_mutex){+.+.}-{4:4}, at: add_one_compat_dev+0xee/0x5c0 drivers/infiniband/core/device.c:979
#4: ffff88801c6b0188 (&root->kernfs_rwsem){++++}-{4:4}, at: kernfs_add_one+0x41/0x520 fs/kernfs/dir.c:791
#5: ffffc90000007be0 ((&hsr->announce_timer)){+.-.}-{0:0}, at: call_timer_fn+0xbe/0x5f0 kernel/time/timer.c:1744
#6: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#6: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#6: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: hsr_announce+0x83/0x360 net/hsr/hsr_device.c:419
#7: ffff88803beb0f30 (&hsr->seqnr_lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:356 [inline]
#7: ffff88803beb0f30 (&hsr->seqnr_lock){+.-.}-{3:3}, at: send_hsr_supervision_frame+0x380/0xcb0 net/hsr/hsr_device.c:330
#8: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#8: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#8: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: hsr_forward_skb+0x9e/0x2860 net/hsr/hsr_forward.c:736
#9: ffffffff8df3d740 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline]
#9: ffffffff8df3d740 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:918 [inline]
#9: ffffffff8df3d740 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x284/0x3740 net/core/dev.c:4736
#10: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#10: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#10: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: br_dev_xmit+0x185/0x1840 net/bridge/br_device.c:52
#11: ffffffff8df3d740 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline]
#11: ffffffff8df3d740 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:918 [inline]
#11: ffffffff8df3d740 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x284/0x3740 net/core/dev.c:4736
#12: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#12: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#12: ffffffff8df3d6e0 (rcu_read_lock){....}-{1:3}, at: hsr_dev_xmit+0x2d/0x360 net/hsr/hsr_device.c:229
stack backtrace:
CPU: 0 UID: 0 PID: 2385 Comm: syz.1.9506 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+0x189/0x250 lib/dump_stack.c:120
print_deadlock_bug+0x28b/0x2a0 kernel/locking/lockdep.c:3041
check_deadlock kernel/locking/lockdep.c:3093 [inline]
validate_chain+0x1a3f/0x2140 kernel/locking/lockdep.c:3895
__lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
__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+0x237/0x360 net/hsr/hsr_device.c:235
__netdev_start_xmit include/linux/netdevice.h:5259 [inline]
netdev_start_xmit include/linux/netdevice.h:5268 [inline]
xmit_one net/core/dev.c:3853 [inline]
dev_hard_start_xmit+0x2d7/0x830 net/core/dev.c:3869
__dev_queue_xmit+0x172a/0x3740 net/core/dev.c:4811
dev_queue_xmit include/linux/netdevice.h:3368 [inline]
br_dev_queue_push_xmit+0x6c5/0x890 net/bridge/br_forward.c:53
NF_HOOK+0x320/0x3c0 include/linux/netfilter.h:318
br_forward_finish+0xd3/0x130 net/bridge/br_forward.c:66
NF_HOOK+0x320/0x3c0 include/linux/netfilter.h:318
__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:191
br_flood+0x31a/0x6a0 net/bridge/br_forward.c:238
br_dev_xmit+0x11b3/0x1840 net/bridge/br_device.c:108
__netdev_start_xmit include/linux/netdevice.h:5259 [inline]
netdev_start_xmit include/linux/netdevice.h:5268 [inline]
xmit_one net/core/dev.c:3853 [inline]
dev_hard_start_xmit+0x2d7/0x830 net/core/dev.c:3869
__dev_queue_xmit+0x172a/0x3740 net/core/dev.c:4811
dev_queue_xmit include/linux/netdevice.h:3368 [inline]
hsr_xmit net/hsr/hsr_forward.c:438 [inline]
hsr_forward_do net/hsr/hsr_forward.c:579 [inline]
hsr_forward_skb+0x158b/0x2860 net/hsr/hsr_forward.c:741
send_hsr_supervision_frame+0x731/0xcb0 net/hsr/hsr_device.c:364
hsr_announce+0x1d5/0x360 net/hsr/hsr_device.c:421
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:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:723
irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1052
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:instrument_atomic_read include/linux/instrumented.h:68 [inline]
RIP: 0010:atomic_long_read include/linux/atomic/atomic-instrumented.h:3188 [inline]
RIP: 0010:rwsem_owner_flags kernel/locking/rwsem.c:283 [inline]
RIP: 0010:rwsem_spin_on_owner+0x1c7/0x2b0 kernel/locking/rwsem.c:764
Code: f0 8d da 8d e8 6a b7 88 00 48 83 3d 02 80 3d 0c 00 0f 84 f9 00 00 00 4c 89 e7 e8 04 a6 d5 ff 90 84 c0 0f 85 a3 00 00 00 f3 90 <48> 89 df be 08 00 00 00 e8 ac b9 88 00 43 80 3c 2f 00 74 08 48 89
RSP: 0018:ffffc9000cfbf220 EFLAGS: 00000246
RAX: ffff888126235000 RBX: ffff88801c6b0120 RCX: ffff888065df1e40
RDX: 0000000000000000 RSI: 0000000000000008 RDI: 0000000000000001
RBP: 0000000000000008 R08: ffff88801c6b0127 R09: 1ffff110038d6024
R10: dffffc0000000000 R11: ffffed10038d6025 R12: 0000000000000001
R13: dffffc0000000000 R14: ffff888065df1e40 R15: 1ffff110038d6024
rwsem_optimistic_spin kernel/locking/rwsem.c:836 [inline]
rwsem_down_write_slowpath+0x20d/0xfe0 kernel/locking/rwsem.c:1117
__down_write_common kernel/locking/rwsem.c:1317 [inline]
__down_write kernel/locking/rwsem.c:1326 [inline]
down_write+0x1ab/0x1f0 kernel/locking/rwsem.c:1591
kernfs_add_one+0x41/0x520 fs/kernfs/dir.c:791
__kernfs_create_file+0x22b/0x2e0 fs/kernfs/file.c:1086
sysfs_add_file_mode_ns+0x238/0x300 fs/sysfs/file.c:313
create_files fs/sysfs/group.c:76 [inline]
internal_create_group+0x66d/0x1110 fs/sysfs/group.c:183
internal_create_groups fs/sysfs/group.c:223 [inline]
sysfs_create_groups+0x59/0x120 fs/sysfs/group.c:249
setup_port drivers/infiniband/core/sysfs.c:1247 [inline]
ib_setup_port_attrs+0xd9b/0x2070 drivers/infiniband/core/sysfs.c:1433
add_one_compat_dev+0x3d6/0x5c0 drivers/infiniband/core/device.c:1005
rdma_dev_init_net+0x1dd/0x270 drivers/infiniband/core/device.c:1221
ops_init+0x35c/0x5c0 net/core/net_namespace.c:137
setup_net+0xfe/0x320 net/core/net_namespace.c:446
copy_net_ns+0x34e/0x4e0 net/core/net_namespace.c:581
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:3129
__do_sys_unshare kernel/fork.c:3200 [inline]
__se_sys_unshare kernel/fork.c:3198 [inline]
__x64_sys_unshare+0x38/0x50 kernel/fork.c:3198
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd92658f749
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:00007fd927471038 EFLAGS: 00000246 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 00007fd9267e6090 RCX: 00007fd92658f749
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000006a040000
RBP: 00007fd926613f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd9267e6128 R14: 00007fd9267e6090 R15: 00007ffd39b04378
----------------
Code disassembly (best guess):
0: f0 8d lock (bad)
2: da 8d e8 6a b7 88 fimull -0x77489518(%rbp)
8: 00 48 83 add %cl,-0x7d(%rax)
b: 3d 02 80 3d 0c cmp $0xc3d8002,%eax
10: 00 0f add %cl,(%rdi)
12: 84 f9 test %bh,%cl
14: 00 00 add %al,(%rax)
16: 00 4c 89 e7 add %cl,-0x19(%rcx,%rcx,4)
1a: e8 04 a6 d5 ff call 0xffd5a623
1f: 90 nop
20: 84 c0 test %al,%al
22: 0f 85 a3 00 00 00 jne 0xcb
28: f3 90 pause
* 2a: 48 89 df mov %rbx,%rdi <-- trapping instruction
2d: be 08 00 00 00 mov $0x8,%esi
32: e8 ac b9 88 00 call 0x88b9e3
37: 43 80 3c 2f 00 cmpb $0x0,(%r15,%r13,1)
3c: 74 08 je 0x46
3e: 48 rex.W
3f: 89 .byte 0x89