syzbot

================================
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:
ffff0000d0a11ff0 (slock-AF_PHONET/1){+.?.}-{2:2}, at: __sk_receive_skb+0x154/0x850 net/core/sock.c:560
{SOFTIRQ-ON-W} state was registered at:
  lock_acquire+0x20c/0x63c kernel/locking/lockdep.c:5662
  _raw_spin_lock_nested+0x5c/0x78 kernel/locking/spinlock.c:378
  __sk_receive_skb+0x154/0x850 net/core/sock.c:560
  sk_receive_skb include/net/sock.h:2097 [inline]
  pep_do_rcv+0x4b4/0x758 net/phonet/pep.c:675
  sk_backlog_rcv include/net/sock.h:1138 [inline]
  __release_sock+0x1b4/0x3b4 net/core/sock.c:2945
  release_sock+0x60/0x1bc net/core/sock.c:3511
  pep_sock_accept+0xc7c/0x1360 net/phonet/pep.c:879
  pn_socket_accept+0x120/0x2dc net/phonet/socket.c:304
  do_accept+0x448/0x5fc net/socket.c:1890
  __sys_accept4_file net/socket.c:1931 [inline]
  __sys_accept4+0xb4/0x12c net/socket.c:1961
  __do_sys_accept4 net/socket.c:1972 [inline]
  __se_sys_accept4 net/socket.c:1969 [inline]
  __arm64_sys_accept4+0x9c/0xb8 net/socket.c:1969
  __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
  invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52
  el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
  do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204
  el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
  el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
  el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585
irq event stamp: 484448
hardirqs last  enabled at (484448): [<ffff800011b23ea4>] __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:159 [inline]
hardirqs last  enabled at (484448): [<ffff800011b23ea4>] _raw_spin_unlock_irq+0x3c/0x90 kernel/locking/spinlock.c:202
hardirqs last disabled at (484447): [<ffff800011b23c68>] __raw_spin_lock_irq include/linux/spinlock_api_smp.h:117 [inline]
hardirqs last disabled at (484447): [<ffff800011b23c68>] _raw_spin_lock_irq+0x34/0x98 kernel/locking/spinlock.c:170
softirqs last  enabled at (484376): [<ffff8000081ac394>] softirq_handle_end kernel/softirq.c:439 [inline]
softirqs last  enabled at (484376): [<ffff8000081ac394>] handle_softirqs+0xaec/0xc60 kernel/softirq.c:624
softirqs last disabled at (484381): [<ffff8000081af30c>] run_ksoftirqd+0x7c/0x2ac 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: ffff8000153f72c0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x18/0x54 include/linux/rcupdate.h:349
 #1: ffff0000f1199ff0 (slock-AF_PHONET){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline]
 #1: ffff0000f1199ff0 (slock-AF_PHONET){+.-.}-{2:2}, at: __sk_receive_skb+0x164/0x850 net/core/sock.c:562
 #2: ffff0000f119a070 (sk_lock-AF_PHONET){+.+.}-{0:0}, at: sk_receive_skb include/net/sock.h:2097 [inline]
 #2: ffff0000f119a070 (sk_lock-AF_PHONET){+.+.}-{0:0}, at: phonet_rcv+0x600/0xa4c net/phonet/af_phonet.c:-1

stack backtrace:
CPU: 0 PID: 15 Comm: ksoftirqd/0 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call trace:
 dump_backtrace+0x1c0/0x1ec arch/arm64/kernel/stacktrace.c:158
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165
 __dump_stack+0x30/0x40 lib/dump_stack.c:88
 dump_stack_lvl+0xf4/0x15c lib/dump_stack.c:106
 dump_stack+0x1c/0x5c lib/dump_stack.c:113
 print_usage_bug+0x4c0/0x6d8 kernel/locking/lockdep.c:3957
 valid_state kernel/locking/lockdep.c:3969 [inline]
 mark_lock_irq+0x850/0xab0 kernel/locking/lockdep.c:-1
 mark_lock+0x224/0x320 kernel/locking/lockdep.c:4628
 mark_usage kernel/locking/lockdep.c:-1 [inline]
 __lock_acquire+0xa78/0x6800 kernel/locking/lockdep.c:5003
 lock_acquire+0x20c/0x63c kernel/locking/lockdep.c:5662
 _raw_spin_lock_nested+0x5c/0x78 kernel/locking/spinlock.c:378
 __sk_receive_skb+0x154/0x850 net/core/sock.c:560
 sk_receive_skb include/net/sock.h:2097 [inline]
 pep_do_rcv+0x4b4/0x758 net/phonet/pep.c:675
 sk_backlog_rcv include/net/sock.h:1138 [inline]
 __sk_receive_skb+0x3d0/0x850 net/core/sock.c:569
 sk_receive_skb include/net/sock.h:2097 [inline]
 phonet_rcv+0x600/0xa4c net/phonet/af_phonet.c:-1
 __netif_receive_skb_one_core net/core/dev.c:5619 [inline]
 __netif_receive_skb+0xcc/0x2a8 net/core/dev.c:5733
 process_backlog+0x408/0x710 net/core/dev.c:6061
 __napi_poll+0xb4/0x3f0 net/core/dev.c:6628
 napi_poll net/core/dev.c:6695 [inline]
 net_rx_action+0x514/0xb18 net/core/dev.c:6809
 handle_softirqs+0x318/0xc60 kernel/softirq.c:596
 run_ksoftirqd+0x7c/0x2ac kernel/softirq.c:968
 smpboot_thread_fn+0x4b0/0x964 kernel/smpboot.c:164
 kthread+0x250/0x2d8 kernel/kthread.c:376
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:850