syzbot

================================
WARNING: inconsistent lock state
syzkaller #0 Not tainted
--------------------------------
inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
syz.9.1680/14161 [HC0[0]:SC1[1]:HE1:SE0] takes:
ffff888025dd0d30 (slock-AF_PHONET/1){+.?.}-{2:2}, at: __sk_receive_skb+0x180/0x990 net/core/sock.c:564
{SOFTIRQ-ON-W} state was registered at:
  lock_acquire+0x19e/0x420 kernel/locking/lockdep.c:5754
  _raw_spin_lock_nested+0x32/0x50 kernel/locking/spinlock.c:378
  __sk_receive_skb+0x180/0x990 net/core/sock.c:564
  sk_receive_skb include/net/sock.h:2071 [inline]
  pep_do_rcv+0x682/0xa90 net/phonet/pep.c:675
  sk_backlog_rcv include/net/sock.h:1142 [inline]
  __release_sock+0x1e5/0x460 net/core/sock.c:3011
  release_sock+0x5f/0x1c0 net/core/sock.c:3550
  pep_sock_accept+0xd58/0x12d0 net/phonet/pep.c:879
  pn_socket_accept+0x12a/0x370 net/phonet/socket.c:304
  do_accept+0x4d8/0x6c0 net/socket.c:1937
  __sys_accept4_file net/socket.c:1977 [inline]
  __sys_accept4+0x9b/0x100 net/socket.c:2007
  __do_sys_accept4 net/socket.c:2018 [inline]
  __se_sys_accept4 net/socket.c:2015 [inline]
  __x64_sys_accept4+0x9a/0xb0 net/socket.c:2015
  do_syscall_x64 arch/x86/entry/common.c:46 [inline]
  do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
  entry_SYSCALL_64_after_hwframe+0x68/0xd2
irq event stamp: 3854
hardirqs last  enabled at (3854): [<ffffffff8a91c603>] __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:159 [inline]
hardirqs last  enabled at (3854): [<ffffffff8a91c603>] _raw_spin_unlock_irq+0x23/0x50 kernel/locking/spinlock.c:202
hardirqs last disabled at (3853): [<ffffffff8a91c3ca>] __raw_spin_lock_irq include/linux/spinlock_api_smp.h:117 [inline]
hardirqs last disabled at (3853): [<ffffffff8a91c3ca>] _raw_spin_lock_irq+0x8a/0xf0 kernel/locking/spinlock.c:170
softirqs last  enabled at (3848): [<ffffffff887b4d79>] local_bh_enable include/linux/bottom_half.h:33 [inline]
softirqs last  enabled at (3848): [<ffffffff887b4d79>] netif_rx+0x79/0x90 net/core/dev.c:5232
softirqs last disabled at (3849): [<ffffffff81526d2a>] do_softirq+0xfa/0x1a0 kernel/softirq.c:479

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 ***

5 locks held by syz.9.1680/14161:
 #0: ffff88807f2f0e20 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:804 [inline]
 #0: ffff88807f2f0e20 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: __sock_release net/socket.c:658 [inline]
 #0: ffff88807f2f0e20 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: sock_close+0x9b/0x230 net/socket.c:1420
 #1: ffff888025dd0770 (sk_lock-AF_PHONET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1780 [inline]
 #1: ffff888025dd0770 (sk_lock-AF_PHONET){+.+.}-{0:0}, at: pep_sock_close+0x86/0x5b0 net/phonet/pep.c:742
 #2: ffffffff8d132120 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
 #2: ffffffff8d132120 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline]
 #2: ffffffff8d132120 (rcu_read_lock){....}-{1:2}, at: process_backlog+0x2cf/0x6f0 net/core/dev.c:6087
 #3: ffff888025dd00b0 (slock-AF_PHONET){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline]
 #3: ffff888025dd00b0 (slock-AF_PHONET){+.-.}-{2:2}, at: __sk_receive_skb+0x18f/0x990 net/core/sock.c:566
 #4: ffff888025dd0130 (sk_lock-AF_PHONET){+.+.}-{0:0}, at: sk_receive_skb include/net/sock.h:2071 [inline]
 #4: ffff888025dd0130 (sk_lock-AF_PHONET){+.+.}-{0:0}, at: phonet_rcv+0x78f/0xc80 net/phonet/af_phonet.c:-1

stack backtrace:
CPU: 0 PID: 14161 Comm: syz.9.1680 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Call Trace:
 <IRQ>
 dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106
 valid_state+0x13b/0x1d0 kernel/locking/lockdep.c:4013
 mark_lock_irq+0xad/0x900 kernel/locking/lockdep.c:4216
 mark_lock+0x208/0x320 kernel/locking/lockdep.c:4678
 mark_usage kernel/locking/lockdep.c:-1 [inline]
 __lock_acquire+0xd1a/0x7d40 kernel/locking/lockdep.c:5091
 lock_acquire+0x19e/0x420 kernel/locking/lockdep.c:5754
 _raw_spin_lock_nested+0x32/0x50 kernel/locking/spinlock.c:378
 __sk_receive_skb+0x180/0x990 net/core/sock.c:564
 sk_receive_skb include/net/sock.h:2071 [inline]
 pep_do_rcv+0x682/0xa90 net/phonet/pep.c:675
 sk_backlog_rcv include/net/sock.h:1142 [inline]
 __sk_receive_skb+0x436/0x990 net/core/sock.c:573
 sk_receive_skb include/net/sock.h:2071 [inline]
 phonet_rcv+0x78f/0xc80 net/phonet/af_phonet.c:-1
 __netif_receive_skb_one_core net/core/dev.c:5646 [inline]
 __netif_receive_skb+0xcc/0x290 net/core/dev.c:5760
 process_backlog+0x391/0x6f0 net/core/dev.c:6088
 __napi_poll+0xc0/0x460 net/core/dev.c:6650
 napi_poll net/core/dev.c:6717 [inline]
 net_rx_action+0x616/0xc40 net/core/dev.c:6853
 handle_softirqs+0x280/0x820 kernel/softirq.c:578
 do_softirq+0xfa/0x1a0 kernel/softirq.c:479
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x184/0x1c0 kernel/softirq.c:406
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 netif_rx+0x83/0x90 net/core/dev.c:5232
 pn_send+0x553/0x7f0 net/phonet/af_phonet.c:185
 pn_skb_send+0x218/0x510 net/phonet/af_phonet.c:272
 pep_sock_close+0x2c1/0x5b0 include/linux/skbuff.h:-1
 pn_socket_release+0x95/0xb0 net/phonet/socket.c:34
 __sock_release net/socket.c:659 [inline]
 sock_close+0xbd/0x230 net/socket.c:1420
 __fput+0x234/0x970 fs/file_table.c:384
 task_work_run+0x1d4/0x260 kernel/task_work.c:245
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
 do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fecc339ce59
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fffb6c9ca78 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007fecc3617da0 RCX: 00007fecc339ce59
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007fecc3617da0 R08: 00007fecc3616038 R09: 0000000000000000
R10: 00000000003ffd0c R11: 0000000000000246 R12: 00000000000e7628
R13: 00007fecc361609c R14: 00000000000e736d R15: 00007fecc3616090
 </TASK>