============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
syz.0.2320/13499 is trying to acquire lock:
ffff88807dbbcf30 (&hsr->seqnr_lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:356 [inline]
ffff88807dbbcf30 (&hsr->seqnr_lock){+.-.}-{3:3}, at: hsr_dev_xmit+0x237/0x360 net/hsr/hsr_device.c:235
but task is already holding lock:
ffff888079646f30 (&hsr->seqnr_lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:356 [inline]
ffff888079646f30 (&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
15 locks held by syz.0.2320/13499:
#0: ffff888056fdb0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffff888056fdb130 (&tty->atomic_write_lock){+.+.}-{4:4}, at: tty_write_lock drivers/tty/tty_io.c:939 [inline]
#1: ffff888056fdb130 (&tty->atomic_write_lock){+.+.}-{4:4}, at: iterate_tty_write drivers/tty/tty_io.c:958 [inline]
#1: ffff888056fdb130 (&tty->atomic_write_lock){+.+.}-{4:4}, at: file_tty_write+0x211/0xa20 drivers/tty/tty_io.c:1081
#2: ffff888056fdb2e8 (&tty->termios_rwsem){++++}-{4:4}, at: n_tty_write+0x1e0/0x1200 drivers/tty/n_tty.c:2360
#3: ffffc90004c5b380 (&ldata->output_lock){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:253 [inline]
#3: ffffc90004c5b380 (&ldata->output_lock){+.+.}-{4:4}, at: process_output drivers/tty/n_tty.c:484 [inline]
#3: ffffc90004c5b380 (&ldata->output_lock){+.+.}-{4:4}, at: n_tty_write+0xde6/0x1200 drivers/tty/n_tty.c:2388
#4: ffffffff8df352c0 (console_lock){+.+.}-{0:0}, at: class_console_lock_constructor include/linux/console.h:669 [inline]
#4: ffffffff8df352c0 (console_lock){+.+.}-{0:0}, at: do_con_write+0x116/0x5210 drivers/tty/vt/vt.c:3193
#5: ffffc90000a08be0 ((&hsr->announce_timer)){+.-.}-{0:0}, at: call_timer_fn+0xbe/0x590 kernel/time/timer.c:1745
#6: ffffffff8df414c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#6: ffffffff8df414c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#6: ffffffff8df414c0 (rcu_read_lock){....}-{1:3}, at: hsr_announce+0x83/0x360 net/hsr/hsr_device.c:419
#7: ffff888079646f30 (&hsr->seqnr_lock){+.-.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:356 [inline]
#7: ffff888079646f30 (&hsr->seqnr_lock){+.-.}-{3:3}, at: send_hsr_supervision_frame+0x380/0xcb0 net/hsr/hsr_device.c:330
#8: ffffffff8df414c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#8: ffffffff8df414c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#8: ffffffff8df414c0 (rcu_read_lock){....}-{1:3}, at: hsr_forward_skb+0x9e/0x2860 net/hsr/hsr_forward.c:736
#9: ffffffff8df41520 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline]
#9: ffffffff8df41520 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:918 [inline]
#9: ffffffff8df41520 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x259/0x3b10 net/core/dev.c:4688
#10: ffffffff8df414c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#10: ffffffff8df414c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#10: ffffffff8df414c0 (rcu_read_lock){....}-{1:3}, at: bond_start_xmit+0xf8/0x1a10 drivers/net/bonding/bond_main.c:5577
#11: ffffffff8df41520 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline]
#11: ffffffff8df41520 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:918 [inline]
#11: ffffffff8df41520 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x259/0x3b10 net/core/dev.c:4688
#12: ffffffff8df414c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#12: ffffffff8df414c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#12: ffffffff8df414c0 (rcu_read_lock){....}-{1:3}, at: br_dev_xmit+0x185/0x1840 net/bridge/br_device.c:52
#13: ffffffff8df41520 (rcu_read_lock_bh){....}-{1:3}, at: local_bh_disable include/linux/bottom_half.h:20 [inline]
#13: ffffffff8df41520 (rcu_read_lock_bh){....}-{1:3}, at: rcu_read_lock_bh include/linux/rcupdate.h:918 [inline]
#13: ffffffff8df41520 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x259/0x3b10 net/core/dev.c:4688
#14: ffffffff8df414c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#14: ffffffff8df414c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#14: ffffffff8df414c0 (rcu_read_lock){....}-{1:3}, at: hsr_dev_xmit+0x2d/0x360 net/hsr/hsr_device.c:229
stack backtrace:
CPU: 1 UID: 0 PID: 13499 Comm: syz.0.2320 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+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+0x117/0x340 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:5248 [inline]
netdev_start_xmit include/linux/netdevice.h:5257 [inline]
xmit_one net/core/dev.c:3845 [inline]
dev_hard_start_xmit+0x2cd/0x800 net/core/dev.c:3861
__dev_queue_xmit+0x1b5b/0x3b10 net/core/dev.c:4763
dev_queue_xmit include/linux/netdevice.h:3365 [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:5248 [inline]
netdev_start_xmit include/linux/netdevice.h:5257 [inline]
xmit_one net/core/dev.c:3845 [inline]
dev_hard_start_xmit+0x2cd/0x800 net/core/dev.c:3861
__dev_queue_xmit+0x1b5b/0x3b10 net/core/dev.c:4763
__bond_start_xmit include/linux/netdevice.h:-1 [inline]
bond_start_xmit+0xdc7/0x1a10 drivers/net/bonding/bond_main.c:5579
__netdev_start_xmit include/linux/netdevice.h:5248 [inline]
netdev_start_xmit include/linux/netdevice.h:5257 [inline]
xmit_one net/core/dev.c:3845 [inline]
dev_hard_start_xmit+0x2cd/0x800 net/core/dev.c:3861
__dev_queue_xmit+0x1b5b/0x3b10 net/core/dev.c:4763
dev_queue_xmit include/linux/netdevice.h:3365 [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+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+0x27d/0x850 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:1055 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1055
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:queue_work_on+0x1f7/0x270 kernel/workqueue.c:2397
Code: 4d 85 ff 75 16 e8 b9 b6 36 00 eb 15 e8 b2 b6 36 00 e8 5d 03 bc 09 4d 85 ff 74 ea e8 a3 b6 36 00 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 04 2e 00 00 00 00 66 43 c7 44 2e 09 00 00 43 c6 44 2e 0b 00
RSP: 0018:ffffc900033f7120 EFLAGS: 00000293
RAX: ffffffff818a304d RBX: ffff8881423bb901 RCX: ffff88802de61e80
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900033f7210 R08: ffffffff8f801377 R09: 1ffffffff1f0026e
R10: dffffc0000000000 R11: fffffbfff1f0026f R12: 0000000000000000
R13: dffffc0000000000 R14: 1ffff9200067ee2c R15: 0000000000000200
bit_putcs+0x1865/0x1bd0 drivers/video/fbdev/core/bitblit.c:-1
fbcon_putcs+0x3a6/0x580 drivers/video/fbdev/core/fbcon.c:1322
con_flush drivers/tty/vt/vt.c:2801 [inline]
do_con_write+0x50d7/0x5210 drivers/tty/vt/vt.c:3238
con_put_char+0x82/0xc0 drivers/tty/vt/vt.c:3573
tty_put_char+0xce/0x160 drivers/tty/tty_io.c:3153
do_output_char+0x6ac/0x970 drivers/tty/n_tty.c:463
process_output drivers/tty/n_tty.c:486 [inline]
n_tty_write+0xdfc/0x1200 drivers/tty/n_tty.c:2388
iterate_tty_write drivers/tty/tty_io.c:1006 [inline]
file_tty_write+0x559/0xa20 drivers/tty/tty_io.c:1081
new_sync_write fs/read_write.c:593 [inline]
vfs_write+0x5c9/0xb30 fs/read_write.c:686
ksys_write+0x145/0x250 fs/read_write.c:738
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc3dc98f749
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:00007fc3dd75e038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fc3dcbe5fa0 RCX: 00007fc3dc98f749
RDX: 0000000000000375 RSI: 0000200000001040 RDI: 0000000000000003
RBP: 00007fc3dca13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc3dcbe6038 R14: 00007fc3dcbe5fa0 R15: 00007fc3dcd0fa28
----------------
Code disassembly (best guess):
0: 4d 85 ff test %r15,%r15
3: 75 16 jne 0x1b
5: e8 b9 b6 36 00 call 0x36b6c3
a: eb 15 jmp 0x21
c: e8 b2 b6 36 00 call 0x36b6c3
11: e8 5d 03 bc 09 call 0x9bc0373
16: 4d 85 ff test %r15,%r15
19: 74 ea je 0x5
1b: e8 a3 b6 36 00 call 0x36b6c3
20: fb sti
21: 48 c7 44 24 40 0e 36 movq $0x45e0360e,0x40(%rsp)
28: e0 45
* 2a: 4b c7 04 2e 00 00 00 movq $0x0,(%r14,%r13,1) <-- trapping instruction
31: 00
32: 66 43 c7 44 2e 09 00 movw $0x0,0x9(%r14,%r13,1)
39: 00
3a: 43 c6 44 2e 0b 00 movb $0x0,0xb(%r14,%r13,1)