============================================
WARNING: possible recursive locking detected
5.15.153-syzkaller #0 Not tainted
--------------------------------------------
dhcpcd/3174 is trying to acquire lock:
ffffffff8dad4258 (unix_gc_lock){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline]
ffffffff8dad4258 (unix_gc_lock){+.+.}-{2:2}, at: unix_notinflight+0x29a/0x390 net/unix/scm.c:72
but task is already holding lock:
ffffffff8dad4258 (unix_gc_lock){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline]
ffffffff8dad4258 (unix_gc_lock){+.+.}-{2:2}, at: unix_gc+0x115/0x1380 net/unix/garbage.c:214
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(unix_gc_lock);
lock(unix_gc_lock);
*** DEADLOCK ***
May be due to missing lock nesting notation
2 locks held by dhcpcd/3174:
#0: ffff888074593810 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:789 [inline]
#0: ffff888074593810 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: __sock_release net/socket.c:648 [inline]
#0: ffff888074593810 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: sock_close+0x98/0x230 net/socket.c:1336
#1: ffffffff8dad4258 (unix_gc_lock){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline]
#1: ffffffff8dad4258 (unix_gc_lock){+.+.}-{2:2}, at: unix_gc+0x115/0x1380 net/unix/garbage.c:214
stack backtrace:
CPU: 1 PID: 3174 Comm: dhcpcd Not tainted 5.15.153-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
print_deadlock_bug kernel/locking/lockdep.c:2946 [inline]
check_deadlock kernel/locking/lockdep.c:2989 [inline]
validate_chain+0x46d2/0x5930 kernel/locking/lockdep.c:3775
__lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012
lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
__raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154
spin_lock include/linux/spinlock.h:363 [inline]
unix_notinflight+0x29a/0x390 net/unix/scm.c:72
unix_detach_fds net/unix/scm.c:134 [inline]
unix_destruct_scm+0x21d/0x350 net/unix/scm.c:145
skb_release_head_state+0xf9/0x230 net/core/skbuff.c:729
skb_release_all net/core/skbuff.c:740 [inline]
__kfree_skb net/core/skbuff.c:756 [inline]
kfree_skb_reason+0x82/0x170 net/core/skbuff.c:776
kfree_skb include/linux/skbuff.h:1123 [inline]
unix_gc+0xb2b/0x1380 net/unix/garbage.c:292
unix_release_sock+0x91c/0xaa0 net/unix/af_unix.c:607
unix_release+0x88/0xc0 net/unix/af_unix.c:950
__sock_release net/socket.c:649 [inline]
sock_close+0xcd/0x230 net/socket.c:1336
__fput+0x3bf/0x890 fs/file_table.c:280
task_work_run+0x129/0x1a0 kernel/task_work.c:164
tracehook_notify_resume include/linux/tracehook.h:189 [inline]
exit_to_user_mode_loop+0x106/0x130 kernel/entry/common.c:175
exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:208
__syscall_exit_to_user_mode_work kernel/entry/common.c:290 [inline]
syscall_exit_to_user_mode+0x5d/0x250 kernel/entry/common.c:301
do_syscall_64+0x49/0xb0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7fdede9980a8
Code: 48 8b 05 83 9d 0d 00 64 c7 00 16 00 00 00 83 c8 ff 48 83 c4 20 5b c3 64 8b 04 25 18 00 00 00 85 c0 75 20 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 76 5b 48 8b 15 51 9d 0d 00 f7 d8 64 89 02 48 83
RSP: 002b:00007ffc93f31cf8 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000004 RCX: 00007fdede9980a8
RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000005
RBP: 00007ffc93f520a8 R08: 0000000000000007 R09: 69906f7023515725
R10: 0000000000004000 R11: 0000000000000246 R12: 00005620c764d4e0
R13: 00007ffc93f41ee8 R14: 0000000000000148 R15: 0000000000000004
</TASK>