================================
WARNING: inconsistent lock state
syzkaller #0 Not tainted
--------------------------------
inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
ksoftirqd/0/15 [HC0[0]:SC1[1]:HE1:SE0] takes:
ffff88804e4638f0 (slock-AF_PHONET/1){+.?.}-{2:2}, at: __sk_receive_skb+0x17c/0x980 net/core/sock.c:560
{SOFTIRQ-ON-W} state was registered at:
  lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5662
  _raw_spin_lock_nested+0x2e/0x40 kernel/locking/spinlock.c:378
  __sk_receive_skb+0x17c/0x980 net/core/sock.c:560
  sk_backlog_rcv include/net/sock.h:1138 [inline]
  __release_sock+0x1e1/0x450 net/core/sock.c:2945
  release_sock+0x5b/0x1b0 net/core/sock.c:3511
  pep_sock_accept+0xcb1/0x1200 net/phonet/pep.c:879
  pn_socket_accept+0x126/0x360 net/phonet/socket.c:304
  do_accept+0x509/0x6f0 net/socket.c:1890
  __sys_accept4_file net/socket.c:1931 [inline]
  __sys_accept4+0x97/0x100 net/socket.c:1961
  __do_sys_accept4 net/socket.c:1972 [inline]
  __se_sys_accept4 net/socket.c:1969 [inline]
  __x64_sys_accept4+0x96/0xb0 net/socket.c:1969
  do_syscall_x64 arch/x86/entry/common.c:46 [inline]
  do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
  entry_SYSCALL_64_after_hwframe+0x68/0xd2
irq event stamp: 3257760
hardirqs last  enabled at (3257760): [<ffffffff8a380f3f>] __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:159 [inline]
hardirqs last  enabled at (3257760): [<ffffffff8a380f3f>] _raw_spin_unlock_irq+0x1f/0x40 kernel/locking/spinlock.c:202
hardirqs last disabled at (3257759): [<ffffffff8a380d06>] __raw_spin_lock_irq include/linux/spinlock_api_smp.h:117 [inline]
hardirqs last disabled at (3257759): [<ffffffff8a380d06>] _raw_spin_lock_irq+0x86/0xf0 kernel/locking/spinlock.c:170
softirqs last  enabled at (3257706): [<ffffffff814f96a4>] run_ksoftirqd+0xa4/0x100 kernel/softirq.c:968
softirqs last disabled at (3257711): [<ffffffff814f96a4>] run_ksoftirqd+0xa4/0x100 kernel/softirq.c:968

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(slock-AF_PHONET/1);
  <Interrupt>
    lock(slock-AF_PHONET/1);

 *** DEADLOCK ***

3 locks held by ksoftirqd/0/15:
 #0: ffffffff8cb2d5e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #0: ffffffff8cb2d5e0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #0: ffffffff8cb2d5e0 (rcu_read_lock){....}-{1:2}, at: process_backlog+0x2cb/0x6f0 net/core/dev.c:6060
 #1: ffff88807d1acbb0 (slock-AF_PHONET){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline]
 #1: ffff88807d1acbb0 (slock-AF_PHONET){+.-.}-{2:2}, at: __sk_receive_skb+0x18b/0x980 net/core/sock.c:562
 #2: ffff88807d1acc30 (sk_lock-AF_PHONET){+.+.}-{0:0}, at: sk_receive_skb include/net/sock.h:2097 [inline]
 #2: ffff88807d1acc30 (sk_lock-AF_PHONET){+.+.}-{0:0}, at: phonet_rcv+0x7c5/0xca0 net/phonet/af_phonet.c:405

stack backtrace:
CPU: 0 PID: 15 Comm: ksoftirqd/0 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106
 valid_state+0x13b/0x1d0 kernel/locking/lockdep.c:3969
 mark_lock_irq+0xa9/0x900 kernel/locking/lockdep.c:4172
 mark_lock+0x208/0x320 kernel/locking/lockdep.c:4628
 mark_usage kernel/locking/lockdep.c:-1 [inline]
 __lock_acquire+0xc78/0x7d10 kernel/locking/lockdep.c:5003
 lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5662
 _raw_spin_lock_nested+0x2e/0x40 kernel/locking/spinlock.c:378
 __sk_receive_skb+0x17c/0x980 net/core/sock.c:560
 sk_backlog_rcv include/net/sock.h:1138 [inline]
 __sk_receive_skb+0x432/0x980 net/core/sock.c:569
 sk_receive_skb include/net/sock.h:2097 [inline]
 phonet_rcv+0x7c5/0xca0 net/phonet/af_phonet.c:405
 __netif_receive_skb_one_core net/core/dev.c:5619 [inline]
 __netif_receive_skb+0xcc/0x290 net/core/dev.c:5733
 process_backlog+0x38d/0x6f0 net/core/dev.c:6061
 __napi_poll+0xc0/0x460 net/core/dev.c:6628
 napi_poll net/core/dev.c:6695 [inline]
 net_rx_action+0x5dd/0xb20 net/core/dev.c:6809
 handle_softirqs+0x2a1/0x930 kernel/softirq.c:596
 run_ksoftirqd+0xa4/0x100 kernel/softirq.c:968
 smpboot_thread_fn+0x64a/0xa40 kernel/smpboot.c:164
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
vkms_vblank_simulate: vblank timer overrun